Soil moisture has important effects on fuel availability, but is often assessed using drought ind... more Soil moisture has important effects on fuel availability, but is often assessed using drought indices at coarse spatial resolution, without accounting for the fine-scale spatial effects of terrain and canopy variation on forest floor moisture. In this study, we examined the spatial variability of air temperature, litter temperature and near-surface soil moisture (theta, 0–100 mm) using data from field experiments at 17 sites in southeast Australia, covering a range of topographic aspects and vegetation types, within climates from semiarid to wet montane. Temperatures and theta in mountainous environments were found to vary at much finer spatial scales than typical drought index grid dimensions (several kilometres). Using terrain elevation, local insolation ratio and plant area index, we developed semi-empirical microclimate models for air and litter temperatures, then used modelled temperatures as input into calculations of the Keetch–Byram Drought Index, a widely used index of soil moisture deficit. Drought index results based on predicted litter temperature were found to explain 91% of the spatial variation in near-surface soil moisture at our experimental sites. These results suggest the potential for routine hillslope-scale predictions of forest floor moisture status, which may be useful in the management of fire, particularly prescribed burning, in complex terrain.
This final project report describes a method for generating carbon and heat emission estimates fr... more This final project report describes a method for generating carbon and heat emission estimates from active bushfires and scheduled prescribed burns. This work forms part of a larger project seeking to build a smoke forecasting system for the state of Victoria, in south-east Australia. The report describes extensions to the University of Melbourne PHOENIX RapidFire bushfire propagation model, including the development of a new prescribed burn simulator which is the first of its kind in Australia.
Air pollution is always present in our cities, and often in rural areas as well. Over time, the p... more Air pollution is always present in our cities, and often in rural areas as well. Over time, the patterns of air pollution are changing, because of changes in technology, climate, population and industry. This study seeks a scientific understanding of likely future trends in air quality in Victoria. This information will be used to develop policies and strategies to control air pollution, now and in the future.
It was found that changes in vehicle technology and population are the main factors likely to affect urban air quality impacts over the next two decades. Air pollution emissions in 2030 were estimated under three plausible future scenarios, which were then used in air quality modelling. Population change between 2006 and 2030 was examined using a population distribution model based on census data and published data on population growth.
By 2030, it is predicted that total motor vehicle exhaust emissions will have significantly reduced, despite the large growth expected in the use of cars and trucks. This is because improved technology is entering the vehicle fleet faster than the rate of growth in vehicle use. The net effect is a reduction in the impacts of exhaust-related pollutants: carbon monoxide, nitrogen dioxide and air toxics such as benzene. This prediction is supported by independent data. When long-term measurements of these pollutants in Melbourne were examined, a clear downward trend was seen.
For emissions that are linked to domestic and business activities, significant increases are expected due to the 45 per cent population growth projected for the Melbourne and Geelong areas between 2006 and 2030. Unless pollutant concentrations are zero or low enough to have no effect, population growth itself is a driver of increased impact, as the health burden for a given pollution situation is increased as more people are exposed. Our population is also predicted to age significantly. Between 2006 and 2030 we are expecting a large increase in the number of people aged 65 years or older. This is important because people in this age category are known to be more sensitive to air pollution.
Climate change may also affect our air quality in the future. Over the next two decades, climate change will not significantly affect urban air pollution. However, in the decades beyond 2030, if emissions are not kept in check, climate change is predicted to cause significant increases in summer smog (ozone). It is also possible that the frequency of droughts may increase, which would lead to an increase in particle air pollution from bushfires and wind-blown dust.
Under the most likely future scenario, the net effect of climate change, growth in domestic and small business emissions, and growth in the receiving population is an increase in population exposure to fine particles (PM2.5) and ozone (O3) between 2006 and 2030. Population exposure is a measure of the overall ‘dose’ of pollution received by a community over a period of time, factoring in both pollution levels and population levels. Given that fine particles and ozone are currently of concern in Victoria, it is clear that these two pollutants should be the primary focus of policy effort over the next 10-20 years.
The net effect for nitrogen dioxide (NO2) is a reduction in impact by 2030, under all three future scenarios. Significant reductions are also expected for carbon monoxide (CO) and air toxics (benzene, formaldehyde, toluene and xylenes). Sulfur dioxide (SO2) impacts are extremely low in Melbourne, and this is expected to remain the case despite some industrial growth.
The primary focus of this study was on air quality in the Port Phillip Region, which includes Melbourne and Geelong. Some preliminary work was done to see if statewide air quality impacts due to wind-blown dust and bushfire smoke could be predicted under future climates. Using four global climate models, dust impacts were modelled across Victoria in the year 2070. The predictions indicate a slight increase in extreme dust events and a slight decrease in moderate dust events. A feasibility study was also conducted to see if fire activity and fire emissions could be modelled under future conditions. The study found that with some further research to link fire ignition and fire spread models with smoke emission estimates, it should be possible to estimate future trends in bushfire activity and consequent smoke impacts.
There are clear signs of improvement in many of the air pollutants typically found in our cities – especially those linked to vehicle exhaust. For other pollutants such as particles and ozone, which result from many different emission sources, only gradual changes are expected. As Melbourne grows, the impacts of these pollutants are likely to increase, and in the long term, climate change is likely to increase levels further. Managing particles and ozone will need a coordinated approach to tackle the relevant pollution sources.
Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from a... more Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from atmospheric observations of CCl4 using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) global network, in particular from Cape Grim, Tasmania. Global and Australian emissions are in decline in response to Montreal Protocol restrictions on CCl4 production and consumption for dispersive uses in the developed and developing world. However, atmospheric data-derived emissions are significantly larger than ‘bottom-up’ estimates from direct and indirect CCl4 production, CCl4 transportation and use. Australian CCl4 emissions are not a result of these sources, and the identification of the origin of Australian emissions may provide a clue to the origin of some of these ‘missing’ global sources.
Climate change has been predicted to affect future
air quality, with inevitable consequences for ... more Climate change has been predicted to affect future air quality, with inevitable consequences for health. Quantifying the health effects of air pollution under a changing climate is crucial to provide evidence for actions to safeguard future populations. In this paper, we review published methods for quantifying health impacts to identify optimal approaches and ways in which existing challenges facing this line of research can be addressed. Most studies have employed a simplified methodology, while only a few have reported sensitivity analyses to assess sources of uncertainty. The limited investigations that do exist suggest that examining the health risk estimates should particularly take into account the uncertainty associated with future air pollution emissions scenarios, concentration-response functions, and future population growth and age structures. Knowledge gaps identified for future research include future health impacts from extreme air pollution events, interactions between temperature and air pollution effects on public health under a changing climate, and how population adaptation and behavioural changes in a warmer climate may modify exposure to air pollution and health consequences.
The organisations that manage wildfires are expected to deliver scientifically defensible decisio... more The organisations that manage wildfires are expected to deliver scientifically defensible decisions. However, the limited availability of high quality data restricts the rate at which research can advance. The nature of wildfires contributes to this; they are infrequent, complex events and occur rapidly. While some information about wildfires is usually collected, it is often not of an appropriate standard for research. Valuable information may be discarded or not collected as it is not seen as operationally useful. The harmonisation of fire data management worldwide could increase the availability and quality of information for research. We propose a three tiered approach where agreements are created to standardise data quality, define the scope of information to be collected and establish access protocols for sharing. Standardisation of data collection would facilitate the aggregation of data throughout the world, providing leverage on data collected and reduce unnecessary duplication. If the scope of collection can be expanded, there are a wide range of research fields that stand to benefit. Appropriate data sharing between agencies would increase the value of the data and enable robust conclusions to be reached. It is imperative that the losses caused by severe fires are not in vain; losses should be offset by efforts to maximise the information obtained, helping to prevent a repeat of such events in the future.
Forest fires are periodic occurrences in many parts of the world. Where they coincide with human ... more Forest fires are periodic occurrences in many parts of the world. Where they coincide with human populations, they have the potential to have substantial impacts on human values. Consequently, strategies are adopted by land managers to reduce the probability of fire occurrence and, in the event of a fire, reduce subsequent impacts.
One such strategy has involved the adoption of fire danger ratings. These are levels of alertness that are applied at a regional level on a daily basis. They are based on preceding and forecast weather and provide an indication of the potential severity of fire behaviour. Danger ratings are generally based on weather derived indices and have limited ability to represent the contribution of landscape attributes to potential impacts, including the properties of vegetation (fuels) and the amount and spatial configuration of vulnerable assets. We propose an alternative method for representing fire danger using fire simulation. An ensemble approach is demonstrated whereby thousands of virtual fires are ignited on a regular grid and simulated on a daily basis using forecast weather with the model PHOENIX RapidFire. Each fire is simulated in succession and burns for a specified period. Fire simulations integrate the contributions of local fuel, topography and weather to fire behaviour. The resultant fires can be aggregated to provide spatially explicit representations of potential spread patterns. These maps can be combined with asset registers to quantify potential impacts and assist with the prioritisation of response and protection measures.
Proceedings of the 20th International Clean Air and Environment Conference, Auckland, Jul 31, 2011
Calculating population exposure to air pollutants requires a knowledge of the spatial and tempora... more Calculating population exposure to air pollutants requires a knowledge of the spatial and temporal patterns of air pollution in relation to the exposed population. Population data are often treated as if everyone remained at their residences all day; this is clearly not the case. Furthermore, peak air pollutant concentrations do not always occur where people are most concentrated; this is especially true for secondary pollutants which may develop many kilometres downwind of source areas.
In order to build improved estimates of population exposure in Melbourne, the 2007 Victorian Integrated Survey of Travel and Activity (VISTA) was used to construct twenty-four maps of the urban population, one for each hour of the day. This data was combined with air pollutant concentrations from a CSIRO grid-based chemical transport model to estimate exposure of the population, accounting for typical daily movements on weekdays and weekends. A further refinement was to separate the population data into age groups, since younger and older residents travel less than those of working age; with the aim of improving exposure estimates for those with increased vulnerability to air pollution.
The results are compared with the more conventional approaches of assuming either a single population total for the city, or a map of fixed residential population. It was found that average dynamic exposure estimates were slightly higher than estimates based on residential population, whilst peak dynamic exposure estimates were significantly higher.
Climate change may alter patterns of air pollution in
urban environments, through changes to wind... more Climate change may alter patterns of air pollution in urban environments, through changes to wind speeds, temperatures and other climate parameters. This project reviewed the relevant literature, then made use of CSIRO climate forecasts dynamically downscaled (Mk3 -> CCAM -> TAPM) to a 5 km grid over Melbourne, Australia, with the aim of discerning possible climate-related trends in air quality. Summer photochemical smog is examined using a statistical method for predicting urban ozone, based on projected climate parameters and several years of ground-based ozone measurements. General air quality over the autumn-winter period is considered by calculating airshed ventilation rate and vertical stability, which provide an indication of air pollution potential. Analyses were conducted using only a single IPCC scenario (A2) to obtain preliminary estimates of likely trends. Results indicate that climate change may cause some worsening of air quality in Melbourne over the next 50 years.
Since the 1970s, EPA Victoria has been working to address community concerns about air quality. C... more Since the 1970s, EPA Victoria has been working to address community concerns about air quality. City pollution levels have fallen significantly since monitoring began in 1979. In the ten years since 1995, the rate of improvement has slowed, and for some pollutants, no improvement can be detected.
With concerted effort from all community sectors, these pollutant levels could be driven further down (EPA, 2000). In practice, many other serious environmental concerns are taking priority, in particular, water and climate change. This is despite the fact that currently levels of air pollution are having direct impacts on human health in Australian cities (Howie et al., 2005).
Although clear gains have been made, there are still many Victorian residents with air quality concerns. The problems are often regional or local in scale. Regional examples include the dust storms frequently experienced by Mildura residents (EPA, 2005a), and the smoke impacts of prescribed burning in the Latrobe Valley (EPA, 2005b).
Local scale examples include the unpleasant odours experienced by residents in mixed industrial/residential suburbs, or by residents downwind of intensive farming activities. As residential development encroaches on areas previously considered commercial or rural, we can expect more problems of this type.
On an even smaller scale, indoor air quality is recognised as a potentially serious problem for human health (EA, 2001, p.147). Indoor air is a genuine public health issue, not simply one of personal choice, because good policy can significantly improve indoor air conditions in both public places and private homes. Smoking bans in various public venues have received broad support, and studies have demonstrated the productivity benefits of good indoor air quality (DEH, 2005).
If there is a genuine shift in public concern about air quality away from city-scale ‘smog’ towards local scale problems, how should government respond, and how should responsibility be divided between state and local government? This paper aims to explore the major issues and possible ways forward.
Victoria has recently experienced a number of days of extreme air pollution as a result of drough... more Victoria has recently experienced a number of days of extreme air pollution as a result of drought and bushfires. The severity of these events is reviewed with respect to historical patterns. Major dust storms impacted on Melbourne in December 2002, March 2003 and June 2003. They were primarily a result of substantial drought in Victoria and southern NSW with consequent loss of soil under high wind conditions. These events are analysed in terms of particle size fractions (PM10 vs bsp), wind changes, wind run, and rainfall during the preceding weeks. In January and February 2003, severe bushfires in South East Australia also caused high particle levels (both PM10 and bsp), and generated significant community concern about air quality. Particle readings show the highest ever levels measured by EPA Victoria. Some reflections are provided on the role of EPA during these air quality events in terms of providing clear and useful information to the public.
A comprehensive reconstruction of the air quality database maintained by EPA Victoria has resulte... more A comprehensive reconstruction of the air quality database maintained by EPA Victoria has resulted in significant benefits to clients wanting air quality information. The new system begins with hourly measurements, derives various useful statistics (daily, monthly, and annual), automatically checks compliance with national & state policies, and stores the results in an easily accessible database format. The first public use of this system will be the “Air Quality for Kids” website which allows school children access to comprehensive charts and tables of air quality information. By automatically transforming “data” into “information”, EPA is better placed to provide timely products for each of our target audiences, including national and state government, researchers and students.
Traditional exposure assessment combines population data with one of three pollution measures - a... more Traditional exposure assessment combines population data with one of three pollution measures - a particular percentile of air pollution data, the annual maximum (worst case), or a concentration-time integral. Although these approaches are useful and can form part of a risk assessment, they contain some inherent limitations in their handling of the multi-dimensional nature of exposure data, and present only a partial summary of exposure patterns. To overcome these limitations, a new technique is proposed. The number of personal exposure events, in units of ‘person-events per year’, is calculated using spatial interpolation of the full frequency distribution of pollution data, combined with a map of population. It is assumed that a continuous statistical distribution of pollution concentrations exists at each monitoring site, which is approximated by measurements; and that the parameters of this distribution can be spatially interpolated, to produce a spatial and temporal model of air pollution data. All major Australian cities and industrial towns have been analysed; results are presented here for Melbourne.
Shrinkage and warpage analysis is now an important part of Computer Aided Engineering (CAE) for i... more Shrinkage and warpage analysis is now an important part of Computer Aided Engineering (CAE) for injection molded components. The theory behind this analysis (including effects of crystallinity, orientation and cooling stress relaxation) is presented, along with a number of case studies showing the successful application of this technology.
Prediction of warpage. of injection molded components requires that geometric nonlinearity be tak... more Prediction of warpage. of injection molded components requires that geometric nonlinearity be taken into account. Geometrical nonlinearity arises because the stiffness of a component changes as it deforms. Nonlinearity is also needed for prediction of the response of a thin-walled component to external loading. A prelude to a nonlinear analysis is buckling analysis, which can in many cases give an accurate prediction of buckling load in considerably less CPU time than a full nonlinear analysis. In the case of externally loaded components, this buckling analysis should take into account the prestressed nature of injection molded components. This has been done by an extension to classical buckling analysis.
Soil moisture has important effects on fuel availability, but is often assessed using drought ind... more Soil moisture has important effects on fuel availability, but is often assessed using drought indices at coarse spatial resolution, without accounting for the fine-scale spatial effects of terrain and canopy variation on forest floor moisture. In this study, we examined the spatial variability of air temperature, litter temperature and near-surface soil moisture (theta, 0–100 mm) using data from field experiments at 17 sites in southeast Australia, covering a range of topographic aspects and vegetation types, within climates from semiarid to wet montane. Temperatures and theta in mountainous environments were found to vary at much finer spatial scales than typical drought index grid dimensions (several kilometres). Using terrain elevation, local insolation ratio and plant area index, we developed semi-empirical microclimate models for air and litter temperatures, then used modelled temperatures as input into calculations of the Keetch–Byram Drought Index, a widely used index of soil moisture deficit. Drought index results based on predicted litter temperature were found to explain 91% of the spatial variation in near-surface soil moisture at our experimental sites. These results suggest the potential for routine hillslope-scale predictions of forest floor moisture status, which may be useful in the management of fire, particularly prescribed burning, in complex terrain.
This final project report describes a method for generating carbon and heat emission estimates fr... more This final project report describes a method for generating carbon and heat emission estimates from active bushfires and scheduled prescribed burns. This work forms part of a larger project seeking to build a smoke forecasting system for the state of Victoria, in south-east Australia. The report describes extensions to the University of Melbourne PHOENIX RapidFire bushfire propagation model, including the development of a new prescribed burn simulator which is the first of its kind in Australia.
Air pollution is always present in our cities, and often in rural areas as well. Over time, the p... more Air pollution is always present in our cities, and often in rural areas as well. Over time, the patterns of air pollution are changing, because of changes in technology, climate, population and industry. This study seeks a scientific understanding of likely future trends in air quality in Victoria. This information will be used to develop policies and strategies to control air pollution, now and in the future.
It was found that changes in vehicle technology and population are the main factors likely to affect urban air quality impacts over the next two decades. Air pollution emissions in 2030 were estimated under three plausible future scenarios, which were then used in air quality modelling. Population change between 2006 and 2030 was examined using a population distribution model based on census data and published data on population growth.
By 2030, it is predicted that total motor vehicle exhaust emissions will have significantly reduced, despite the large growth expected in the use of cars and trucks. This is because improved technology is entering the vehicle fleet faster than the rate of growth in vehicle use. The net effect is a reduction in the impacts of exhaust-related pollutants: carbon monoxide, nitrogen dioxide and air toxics such as benzene. This prediction is supported by independent data. When long-term measurements of these pollutants in Melbourne were examined, a clear downward trend was seen.
For emissions that are linked to domestic and business activities, significant increases are expected due to the 45 per cent population growth projected for the Melbourne and Geelong areas between 2006 and 2030. Unless pollutant concentrations are zero or low enough to have no effect, population growth itself is a driver of increased impact, as the health burden for a given pollution situation is increased as more people are exposed. Our population is also predicted to age significantly. Between 2006 and 2030 we are expecting a large increase in the number of people aged 65 years or older. This is important because people in this age category are known to be more sensitive to air pollution.
Climate change may also affect our air quality in the future. Over the next two decades, climate change will not significantly affect urban air pollution. However, in the decades beyond 2030, if emissions are not kept in check, climate change is predicted to cause significant increases in summer smog (ozone). It is also possible that the frequency of droughts may increase, which would lead to an increase in particle air pollution from bushfires and wind-blown dust.
Under the most likely future scenario, the net effect of climate change, growth in domestic and small business emissions, and growth in the receiving population is an increase in population exposure to fine particles (PM2.5) and ozone (O3) between 2006 and 2030. Population exposure is a measure of the overall ‘dose’ of pollution received by a community over a period of time, factoring in both pollution levels and population levels. Given that fine particles and ozone are currently of concern in Victoria, it is clear that these two pollutants should be the primary focus of policy effort over the next 10-20 years.
The net effect for nitrogen dioxide (NO2) is a reduction in impact by 2030, under all three future scenarios. Significant reductions are also expected for carbon monoxide (CO) and air toxics (benzene, formaldehyde, toluene and xylenes). Sulfur dioxide (SO2) impacts are extremely low in Melbourne, and this is expected to remain the case despite some industrial growth.
The primary focus of this study was on air quality in the Port Phillip Region, which includes Melbourne and Geelong. Some preliminary work was done to see if statewide air quality impacts due to wind-blown dust and bushfire smoke could be predicted under future climates. Using four global climate models, dust impacts were modelled across Victoria in the year 2070. The predictions indicate a slight increase in extreme dust events and a slight decrease in moderate dust events. A feasibility study was also conducted to see if fire activity and fire emissions could be modelled under future conditions. The study found that with some further research to link fire ignition and fire spread models with smoke emission estimates, it should be possible to estimate future trends in bushfire activity and consequent smoke impacts.
There are clear signs of improvement in many of the air pollutants typically found in our cities – especially those linked to vehicle exhaust. For other pollutants such as particles and ozone, which result from many different emission sources, only gradual changes are expected. As Melbourne grows, the impacts of these pollutants are likely to increase, and in the long term, climate change is likely to increase levels further. Managing particles and ozone will need a coordinated approach to tackle the relevant pollution sources.
Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from a... more Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from atmospheric observations of CCl4 using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) global network, in particular from Cape Grim, Tasmania. Global and Australian emissions are in decline in response to Montreal Protocol restrictions on CCl4 production and consumption for dispersive uses in the developed and developing world. However, atmospheric data-derived emissions are significantly larger than ‘bottom-up’ estimates from direct and indirect CCl4 production, CCl4 transportation and use. Australian CCl4 emissions are not a result of these sources, and the identification of the origin of Australian emissions may provide a clue to the origin of some of these ‘missing’ global sources.
Climate change has been predicted to affect future
air quality, with inevitable consequences for ... more Climate change has been predicted to affect future air quality, with inevitable consequences for health. Quantifying the health effects of air pollution under a changing climate is crucial to provide evidence for actions to safeguard future populations. In this paper, we review published methods for quantifying health impacts to identify optimal approaches and ways in which existing challenges facing this line of research can be addressed. Most studies have employed a simplified methodology, while only a few have reported sensitivity analyses to assess sources of uncertainty. The limited investigations that do exist suggest that examining the health risk estimates should particularly take into account the uncertainty associated with future air pollution emissions scenarios, concentration-response functions, and future population growth and age structures. Knowledge gaps identified for future research include future health impacts from extreme air pollution events, interactions between temperature and air pollution effects on public health under a changing climate, and how population adaptation and behavioural changes in a warmer climate may modify exposure to air pollution and health consequences.
The organisations that manage wildfires are expected to deliver scientifically defensible decisio... more The organisations that manage wildfires are expected to deliver scientifically defensible decisions. However, the limited availability of high quality data restricts the rate at which research can advance. The nature of wildfires contributes to this; they are infrequent, complex events and occur rapidly. While some information about wildfires is usually collected, it is often not of an appropriate standard for research. Valuable information may be discarded or not collected as it is not seen as operationally useful. The harmonisation of fire data management worldwide could increase the availability and quality of information for research. We propose a three tiered approach where agreements are created to standardise data quality, define the scope of information to be collected and establish access protocols for sharing. Standardisation of data collection would facilitate the aggregation of data throughout the world, providing leverage on data collected and reduce unnecessary duplication. If the scope of collection can be expanded, there are a wide range of research fields that stand to benefit. Appropriate data sharing between agencies would increase the value of the data and enable robust conclusions to be reached. It is imperative that the losses caused by severe fires are not in vain; losses should be offset by efforts to maximise the information obtained, helping to prevent a repeat of such events in the future.
Forest fires are periodic occurrences in many parts of the world. Where they coincide with human ... more Forest fires are periodic occurrences in many parts of the world. Where they coincide with human populations, they have the potential to have substantial impacts on human values. Consequently, strategies are adopted by land managers to reduce the probability of fire occurrence and, in the event of a fire, reduce subsequent impacts.
One such strategy has involved the adoption of fire danger ratings. These are levels of alertness that are applied at a regional level on a daily basis. They are based on preceding and forecast weather and provide an indication of the potential severity of fire behaviour. Danger ratings are generally based on weather derived indices and have limited ability to represent the contribution of landscape attributes to potential impacts, including the properties of vegetation (fuels) and the amount and spatial configuration of vulnerable assets. We propose an alternative method for representing fire danger using fire simulation. An ensemble approach is demonstrated whereby thousands of virtual fires are ignited on a regular grid and simulated on a daily basis using forecast weather with the model PHOENIX RapidFire. Each fire is simulated in succession and burns for a specified period. Fire simulations integrate the contributions of local fuel, topography and weather to fire behaviour. The resultant fires can be aggregated to provide spatially explicit representations of potential spread patterns. These maps can be combined with asset registers to quantify potential impacts and assist with the prioritisation of response and protection measures.
Proceedings of the 20th International Clean Air and Environment Conference, Auckland, Jul 31, 2011
Calculating population exposure to air pollutants requires a knowledge of the spatial and tempora... more Calculating population exposure to air pollutants requires a knowledge of the spatial and temporal patterns of air pollution in relation to the exposed population. Population data are often treated as if everyone remained at their residences all day; this is clearly not the case. Furthermore, peak air pollutant concentrations do not always occur where people are most concentrated; this is especially true for secondary pollutants which may develop many kilometres downwind of source areas.
In order to build improved estimates of population exposure in Melbourne, the 2007 Victorian Integrated Survey of Travel and Activity (VISTA) was used to construct twenty-four maps of the urban population, one for each hour of the day. This data was combined with air pollutant concentrations from a CSIRO grid-based chemical transport model to estimate exposure of the population, accounting for typical daily movements on weekdays and weekends. A further refinement was to separate the population data into age groups, since younger and older residents travel less than those of working age; with the aim of improving exposure estimates for those with increased vulnerability to air pollution.
The results are compared with the more conventional approaches of assuming either a single population total for the city, or a map of fixed residential population. It was found that average dynamic exposure estimates were slightly higher than estimates based on residential population, whilst peak dynamic exposure estimates were significantly higher.
Climate change may alter patterns of air pollution in
urban environments, through changes to wind... more Climate change may alter patterns of air pollution in urban environments, through changes to wind speeds, temperatures and other climate parameters. This project reviewed the relevant literature, then made use of CSIRO climate forecasts dynamically downscaled (Mk3 -> CCAM -> TAPM) to a 5 km grid over Melbourne, Australia, with the aim of discerning possible climate-related trends in air quality. Summer photochemical smog is examined using a statistical method for predicting urban ozone, based on projected climate parameters and several years of ground-based ozone measurements. General air quality over the autumn-winter period is considered by calculating airshed ventilation rate and vertical stability, which provide an indication of air pollution potential. Analyses were conducted using only a single IPCC scenario (A2) to obtain preliminary estimates of likely trends. Results indicate that climate change may cause some worsening of air quality in Melbourne over the next 50 years.
Since the 1970s, EPA Victoria has been working to address community concerns about air quality. C... more Since the 1970s, EPA Victoria has been working to address community concerns about air quality. City pollution levels have fallen significantly since monitoring began in 1979. In the ten years since 1995, the rate of improvement has slowed, and for some pollutants, no improvement can be detected.
With concerted effort from all community sectors, these pollutant levels could be driven further down (EPA, 2000). In practice, many other serious environmental concerns are taking priority, in particular, water and climate change. This is despite the fact that currently levels of air pollution are having direct impacts on human health in Australian cities (Howie et al., 2005).
Although clear gains have been made, there are still many Victorian residents with air quality concerns. The problems are often regional or local in scale. Regional examples include the dust storms frequently experienced by Mildura residents (EPA, 2005a), and the smoke impacts of prescribed burning in the Latrobe Valley (EPA, 2005b).
Local scale examples include the unpleasant odours experienced by residents in mixed industrial/residential suburbs, or by residents downwind of intensive farming activities. As residential development encroaches on areas previously considered commercial or rural, we can expect more problems of this type.
On an even smaller scale, indoor air quality is recognised as a potentially serious problem for human health (EA, 2001, p.147). Indoor air is a genuine public health issue, not simply one of personal choice, because good policy can significantly improve indoor air conditions in both public places and private homes. Smoking bans in various public venues have received broad support, and studies have demonstrated the productivity benefits of good indoor air quality (DEH, 2005).
If there is a genuine shift in public concern about air quality away from city-scale ‘smog’ towards local scale problems, how should government respond, and how should responsibility be divided between state and local government? This paper aims to explore the major issues and possible ways forward.
Victoria has recently experienced a number of days of extreme air pollution as a result of drough... more Victoria has recently experienced a number of days of extreme air pollution as a result of drought and bushfires. The severity of these events is reviewed with respect to historical patterns. Major dust storms impacted on Melbourne in December 2002, March 2003 and June 2003. They were primarily a result of substantial drought in Victoria and southern NSW with consequent loss of soil under high wind conditions. These events are analysed in terms of particle size fractions (PM10 vs bsp), wind changes, wind run, and rainfall during the preceding weeks. In January and February 2003, severe bushfires in South East Australia also caused high particle levels (both PM10 and bsp), and generated significant community concern about air quality. Particle readings show the highest ever levels measured by EPA Victoria. Some reflections are provided on the role of EPA during these air quality events in terms of providing clear and useful information to the public.
A comprehensive reconstruction of the air quality database maintained by EPA Victoria has resulte... more A comprehensive reconstruction of the air quality database maintained by EPA Victoria has resulted in significant benefits to clients wanting air quality information. The new system begins with hourly measurements, derives various useful statistics (daily, monthly, and annual), automatically checks compliance with national & state policies, and stores the results in an easily accessible database format. The first public use of this system will be the “Air Quality for Kids” website which allows school children access to comprehensive charts and tables of air quality information. By automatically transforming “data” into “information”, EPA is better placed to provide timely products for each of our target audiences, including national and state government, researchers and students.
Traditional exposure assessment combines population data with one of three pollution measures - a... more Traditional exposure assessment combines population data with one of three pollution measures - a particular percentile of air pollution data, the annual maximum (worst case), or a concentration-time integral. Although these approaches are useful and can form part of a risk assessment, they contain some inherent limitations in their handling of the multi-dimensional nature of exposure data, and present only a partial summary of exposure patterns. To overcome these limitations, a new technique is proposed. The number of personal exposure events, in units of ‘person-events per year’, is calculated using spatial interpolation of the full frequency distribution of pollution data, combined with a map of population. It is assumed that a continuous statistical distribution of pollution concentrations exists at each monitoring site, which is approximated by measurements; and that the parameters of this distribution can be spatially interpolated, to produce a spatial and temporal model of air pollution data. All major Australian cities and industrial towns have been analysed; results are presented here for Melbourne.
Shrinkage and warpage analysis is now an important part of Computer Aided Engineering (CAE) for i... more Shrinkage and warpage analysis is now an important part of Computer Aided Engineering (CAE) for injection molded components. The theory behind this analysis (including effects of crystallinity, orientation and cooling stress relaxation) is presented, along with a number of case studies showing the successful application of this technology.
Prediction of warpage. of injection molded components requires that geometric nonlinearity be tak... more Prediction of warpage. of injection molded components requires that geometric nonlinearity be taken into account. Geometrical nonlinearity arises because the stiffness of a component changes as it deforms. Nonlinearity is also needed for prediction of the response of a thin-walled component to external loading. A prelude to a nonlinear analysis is buckling analysis, which can in many cases give an accurate prediction of buckling load in considerably less CPU time than a full nonlinear analysis. In the case of externally loaded components, this buckling analysis should take into account the prestressed nature of injection molded components. This has been done by an extension to classical buckling analysis.
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Papers by Sean Walsh
It was found that changes in vehicle technology and population are the main factors likely to affect urban air quality impacts
over the next two decades. Air pollution emissions in 2030 were estimated under three plausible future scenarios, which
were then used in air quality modelling. Population change between 2006 and 2030 was examined using a population
distribution model based on census data and published data on population growth.
By 2030, it is predicted that total motor vehicle exhaust emissions will have significantly reduced, despite the large growth expected in the use of cars and trucks. This is because improved technology is entering the vehicle fleet faster than the rate of growth in vehicle use. The net effect is a reduction in the impacts of exhaust-related pollutants: carbon monoxide, nitrogen dioxide and air toxics such as benzene. This prediction is supported by independent data. When long-term measurements of these pollutants in Melbourne were examined, a clear downward trend was seen.
For emissions that are linked to domestic and business activities, significant increases are expected due to the 45 per cent population growth projected for the Melbourne and Geelong areas between 2006 and 2030. Unless pollutant concentrations are zero or low enough to have no effect, population growth itself is a driver of increased impact, as the health burden for a given pollution situation is increased as more people are exposed. Our population is also predicted to age significantly. Between 2006 and 2030 we are expecting a large increase in the number of people aged 65 years or older. This is important because people in this age category are known to be more sensitive to air pollution.
Climate change may also affect our air quality in the future. Over the next two decades, climate change will not significantly
affect urban air pollution. However, in the decades beyond 2030, if emissions are not kept in check, climate change is
predicted to cause significant increases in summer smog (ozone). It is also possible that the frequency of droughts may
increase, which would lead to an increase in particle air pollution from bushfires and wind-blown dust.
Under the most likely future scenario, the net effect of climate change, growth in domestic and small business emissions, and
growth in the receiving population is an increase in population exposure to fine particles (PM2.5) and ozone (O3) between
2006 and 2030. Population exposure is a measure of the overall ‘dose’ of pollution received by a community over a period of
time, factoring in both pollution levels and population levels. Given that fine particles and ozone are currently of concern in
Victoria, it is clear that these two pollutants should be the primary focus of policy effort over the next 10-20 years.
The net effect for nitrogen dioxide (NO2) is a reduction in impact by 2030, under all three future scenarios. Significant
reductions are also expected for carbon monoxide (CO) and air toxics (benzene, formaldehyde, toluene and xylenes). Sulfur
dioxide (SO2) impacts are extremely low in Melbourne, and this is expected to remain the case despite some industrial growth.
The primary focus of this study was on air quality in the Port Phillip Region, which includes Melbourne and Geelong. Some
preliminary work was done to see if statewide air quality impacts due to wind-blown dust and bushfire smoke could be
predicted under future climates. Using four global climate models, dust impacts were modelled across Victoria in the year
2070. The predictions indicate a slight increase in extreme dust events and a slight decrease in moderate dust events. A
feasibility study was also conducted to see if fire activity and fire emissions could be modelled under future conditions. The
study found that with some further research to link fire ignition and fire spread models with smoke emission estimates, it
should be possible to estimate future trends in bushfire activity and consequent smoke impacts.
There are clear signs of improvement in many of the air pollutants typically found in our cities – especially those linked to vehicle exhaust. For other pollutants such as particles and ozone, which result from many different emission sources, only
gradual changes are expected. As Melbourne grows, the impacts of these pollutants are likely to increase, and in the long term, climate change is likely to increase levels further. Managing particles and ozone will need a coordinated approach to tackle the relevant pollution sources.
air quality, with inevitable consequences for health. Quantifying
the health effects of air pollution under a changing climate
is crucial to provide evidence for actions to safeguard future
populations. In this paper, we review published methods for
quantifying health impacts to identify optimal approaches and
ways in which existing challenges facing this line of research
can be addressed. Most studies have employed a simplified
methodology, while only a few have reported sensitivity analyses
to assess sources of uncertainty. The limited investigations
that do exist suggest that examining the health risk
estimates should particularly take into account the uncertainty
associated with future air pollution emissions scenarios,
concentration-response functions, and future population
growth and age structures. Knowledge gaps identified for
future research include future health impacts from extreme
air pollution events, interactions between temperature and air
pollution effects on public health under a changing climate,
and how population adaptation and behavioural changes in a
warmer climate may modify exposure to air pollution and
health consequences.
management worldwide could increase the availability and quality of information for research. We propose a three tiered approach where agreements are created to standardise data quality, define the scope of information to be collected and establish access protocols for sharing. Standardisation of data collection would facilitate the aggregation of data throughout the world, providing leverage on data collected and reduce unnecessary duplication. If the scope of collection can be expanded, there are a wide range of research fields that stand to benefit. Appropriate data sharing between agencies would increase the value of the data and enable robust conclusions to be reached. It is imperative that the losses caused by severe fires are not in vain; losses should be offset by efforts to maximise the information obtained, helping to prevent a repeat of such events in the future.
they have the potential to have substantial impacts on human values. Consequently, strategies are adopted by land managers to reduce the probability of fire occurrence and, in the event of a fire, reduce subsequent impacts.
One such strategy has involved the adoption of fire danger ratings. These are levels of alertness that are applied at a regional level on a daily basis. They are based on preceding and forecast weather and provide an indication of the potential severity of fire behaviour. Danger ratings are generally based on weather derived indices and have limited ability to represent the contribution of landscape attributes to potential impacts, including the properties of vegetation (fuels) and the amount and spatial configuration of vulnerable assets. We propose an
alternative method for representing fire danger using fire simulation. An ensemble approach is demonstrated
whereby thousands of virtual fires are ignited on a regular grid and simulated on a daily basis using forecast weather with the model PHOENIX RapidFire. Each fire is simulated in succession and burns for a specified period. Fire simulations integrate the contributions of local fuel, topography and weather to fire behaviour. The resultant fires can be aggregated to provide spatially explicit representations of potential spread patterns. These maps can be combined with asset registers to quantify potential impacts and assist with the prioritisation of
response and protection measures.
In order to build improved estimates of population exposure in Melbourne, the 2007 Victorian Integrated Survey of Travel and Activity (VISTA) was used to construct twenty-four maps of the urban population, one for each hour of the day. This data was combined with air pollutant concentrations from a CSIRO grid-based chemical transport model to estimate exposure of the population, accounting for typical daily movements on weekdays and weekends. A further refinement was to separate the population data into age groups, since younger and older residents travel less than those of working age; with the aim of improving exposure estimates for those with increased vulnerability to air pollution.
The results are compared with the more conventional approaches of assuming either a single population total for the city, or a map of fixed residential population. It was found that average dynamic exposure estimates were slightly higher than estimates based on residential population, whilst peak dynamic exposure estimates were significantly higher.
urban environments, through changes to wind speeds,
temperatures and other climate parameters. This
project reviewed the relevant literature, then made
use of CSIRO climate forecasts dynamically
downscaled (Mk3 -> CCAM -> TAPM) to a 5 km grid
over Melbourne, Australia, with the aim of discerning
possible climate-related trends in air quality. Summer
photochemical smog is examined using a statistical
method for predicting urban ozone, based on
projected climate parameters and several years of
ground-based ozone measurements. General air
quality over the autumn-winter period is considered by
calculating airshed ventilation rate and vertical
stability, which provide an indication of air pollution
potential. Analyses were conducted using only a
single IPCC scenario (A2) to obtain preliminary
estimates of likely trends. Results indicate that climate
change may cause some worsening of air quality in
Melbourne over the next 50 years.
With concerted effort from all community sectors, these pollutant levels could be driven further down (EPA, 2000). In practice, many other serious environmental concerns are taking priority, in particular, water and climate change. This is despite the fact that currently levels of air pollution are having direct impacts on human health in Australian cities (Howie et al., 2005).
Although clear gains have been made, there are still many Victorian residents with air quality concerns. The problems are often regional or local in scale. Regional examples include the dust storms frequently experienced by Mildura residents (EPA, 2005a), and the smoke impacts of prescribed burning in the Latrobe Valley (EPA, 2005b).
Local scale examples include the unpleasant odours experienced by residents in mixed industrial/residential suburbs, or by residents downwind of intensive farming activities. As residential development encroaches on areas previously considered commercial or rural, we can expect more problems of this type.
On an even smaller scale, indoor air quality is recognised as a potentially serious problem for human health (EA, 2001, p.147). Indoor air is a genuine public health issue, not simply one of personal choice, because good policy can significantly improve indoor air conditions in both public places and private homes. Smoking bans in various public venues have received broad support, and studies have demonstrated the productivity benefits of good indoor air quality (DEH, 2005).
If there is a genuine shift in public concern about air quality away from city-scale ‘smog’ towards local scale problems, how should government respond, and how should responsibility be divided between state and local government? This paper aims to explore the major issues and possible ways forward.
nonlinear analysis. In the case of externally loaded components, this buckling analysis should take into account the prestressed nature of injection molded components. This has been done by an extension to classical buckling analysis.
It was found that changes in vehicle technology and population are the main factors likely to affect urban air quality impacts
over the next two decades. Air pollution emissions in 2030 were estimated under three plausible future scenarios, which
were then used in air quality modelling. Population change between 2006 and 2030 was examined using a population
distribution model based on census data and published data on population growth.
By 2030, it is predicted that total motor vehicle exhaust emissions will have significantly reduced, despite the large growth expected in the use of cars and trucks. This is because improved technology is entering the vehicle fleet faster than the rate of growth in vehicle use. The net effect is a reduction in the impacts of exhaust-related pollutants: carbon monoxide, nitrogen dioxide and air toxics such as benzene. This prediction is supported by independent data. When long-term measurements of these pollutants in Melbourne were examined, a clear downward trend was seen.
For emissions that are linked to domestic and business activities, significant increases are expected due to the 45 per cent population growth projected for the Melbourne and Geelong areas between 2006 and 2030. Unless pollutant concentrations are zero or low enough to have no effect, population growth itself is a driver of increased impact, as the health burden for a given pollution situation is increased as more people are exposed. Our population is also predicted to age significantly. Between 2006 and 2030 we are expecting a large increase in the number of people aged 65 years or older. This is important because people in this age category are known to be more sensitive to air pollution.
Climate change may also affect our air quality in the future. Over the next two decades, climate change will not significantly
affect urban air pollution. However, in the decades beyond 2030, if emissions are not kept in check, climate change is
predicted to cause significant increases in summer smog (ozone). It is also possible that the frequency of droughts may
increase, which would lead to an increase in particle air pollution from bushfires and wind-blown dust.
Under the most likely future scenario, the net effect of climate change, growth in domestic and small business emissions, and
growth in the receiving population is an increase in population exposure to fine particles (PM2.5) and ozone (O3) between
2006 and 2030. Population exposure is a measure of the overall ‘dose’ of pollution received by a community over a period of
time, factoring in both pollution levels and population levels. Given that fine particles and ozone are currently of concern in
Victoria, it is clear that these two pollutants should be the primary focus of policy effort over the next 10-20 years.
The net effect for nitrogen dioxide (NO2) is a reduction in impact by 2030, under all three future scenarios. Significant
reductions are also expected for carbon monoxide (CO) and air toxics (benzene, formaldehyde, toluene and xylenes). Sulfur
dioxide (SO2) impacts are extremely low in Melbourne, and this is expected to remain the case despite some industrial growth.
The primary focus of this study was on air quality in the Port Phillip Region, which includes Melbourne and Geelong. Some
preliminary work was done to see if statewide air quality impacts due to wind-blown dust and bushfire smoke could be
predicted under future climates. Using four global climate models, dust impacts were modelled across Victoria in the year
2070. The predictions indicate a slight increase in extreme dust events and a slight decrease in moderate dust events. A
feasibility study was also conducted to see if fire activity and fire emissions could be modelled under future conditions. The
study found that with some further research to link fire ignition and fire spread models with smoke emission estimates, it
should be possible to estimate future trends in bushfire activity and consequent smoke impacts.
There are clear signs of improvement in many of the air pollutants typically found in our cities – especially those linked to vehicle exhaust. For other pollutants such as particles and ozone, which result from many different emission sources, only
gradual changes are expected. As Melbourne grows, the impacts of these pollutants are likely to increase, and in the long term, climate change is likely to increase levels further. Managing particles and ozone will need a coordinated approach to tackle the relevant pollution sources.
air quality, with inevitable consequences for health. Quantifying
the health effects of air pollution under a changing climate
is crucial to provide evidence for actions to safeguard future
populations. In this paper, we review published methods for
quantifying health impacts to identify optimal approaches and
ways in which existing challenges facing this line of research
can be addressed. Most studies have employed a simplified
methodology, while only a few have reported sensitivity analyses
to assess sources of uncertainty. The limited investigations
that do exist suggest that examining the health risk
estimates should particularly take into account the uncertainty
associated with future air pollution emissions scenarios,
concentration-response functions, and future population
growth and age structures. Knowledge gaps identified for
future research include future health impacts from extreme
air pollution events, interactions between temperature and air
pollution effects on public health under a changing climate,
and how population adaptation and behavioural changes in a
warmer climate may modify exposure to air pollution and
health consequences.
management worldwide could increase the availability and quality of information for research. We propose a three tiered approach where agreements are created to standardise data quality, define the scope of information to be collected and establish access protocols for sharing. Standardisation of data collection would facilitate the aggregation of data throughout the world, providing leverage on data collected and reduce unnecessary duplication. If the scope of collection can be expanded, there are a wide range of research fields that stand to benefit. Appropriate data sharing between agencies would increase the value of the data and enable robust conclusions to be reached. It is imperative that the losses caused by severe fires are not in vain; losses should be offset by efforts to maximise the information obtained, helping to prevent a repeat of such events in the future.
they have the potential to have substantial impacts on human values. Consequently, strategies are adopted by land managers to reduce the probability of fire occurrence and, in the event of a fire, reduce subsequent impacts.
One such strategy has involved the adoption of fire danger ratings. These are levels of alertness that are applied at a regional level on a daily basis. They are based on preceding and forecast weather and provide an indication of the potential severity of fire behaviour. Danger ratings are generally based on weather derived indices and have limited ability to represent the contribution of landscape attributes to potential impacts, including the properties of vegetation (fuels) and the amount and spatial configuration of vulnerable assets. We propose an
alternative method for representing fire danger using fire simulation. An ensemble approach is demonstrated
whereby thousands of virtual fires are ignited on a regular grid and simulated on a daily basis using forecast weather with the model PHOENIX RapidFire. Each fire is simulated in succession and burns for a specified period. Fire simulations integrate the contributions of local fuel, topography and weather to fire behaviour. The resultant fires can be aggregated to provide spatially explicit representations of potential spread patterns. These maps can be combined with asset registers to quantify potential impacts and assist with the prioritisation of
response and protection measures.
In order to build improved estimates of population exposure in Melbourne, the 2007 Victorian Integrated Survey of Travel and Activity (VISTA) was used to construct twenty-four maps of the urban population, one for each hour of the day. This data was combined with air pollutant concentrations from a CSIRO grid-based chemical transport model to estimate exposure of the population, accounting for typical daily movements on weekdays and weekends. A further refinement was to separate the population data into age groups, since younger and older residents travel less than those of working age; with the aim of improving exposure estimates for those with increased vulnerability to air pollution.
The results are compared with the more conventional approaches of assuming either a single population total for the city, or a map of fixed residential population. It was found that average dynamic exposure estimates were slightly higher than estimates based on residential population, whilst peak dynamic exposure estimates were significantly higher.
urban environments, through changes to wind speeds,
temperatures and other climate parameters. This
project reviewed the relevant literature, then made
use of CSIRO climate forecasts dynamically
downscaled (Mk3 -> CCAM -> TAPM) to a 5 km grid
over Melbourne, Australia, with the aim of discerning
possible climate-related trends in air quality. Summer
photochemical smog is examined using a statistical
method for predicting urban ozone, based on
projected climate parameters and several years of
ground-based ozone measurements. General air
quality over the autumn-winter period is considered by
calculating airshed ventilation rate and vertical
stability, which provide an indication of air pollution
potential. Analyses were conducted using only a
single IPCC scenario (A2) to obtain preliminary
estimates of likely trends. Results indicate that climate
change may cause some worsening of air quality in
Melbourne over the next 50 years.
With concerted effort from all community sectors, these pollutant levels could be driven further down (EPA, 2000). In practice, many other serious environmental concerns are taking priority, in particular, water and climate change. This is despite the fact that currently levels of air pollution are having direct impacts on human health in Australian cities (Howie et al., 2005).
Although clear gains have been made, there are still many Victorian residents with air quality concerns. The problems are often regional or local in scale. Regional examples include the dust storms frequently experienced by Mildura residents (EPA, 2005a), and the smoke impacts of prescribed burning in the Latrobe Valley (EPA, 2005b).
Local scale examples include the unpleasant odours experienced by residents in mixed industrial/residential suburbs, or by residents downwind of intensive farming activities. As residential development encroaches on areas previously considered commercial or rural, we can expect more problems of this type.
On an even smaller scale, indoor air quality is recognised as a potentially serious problem for human health (EA, 2001, p.147). Indoor air is a genuine public health issue, not simply one of personal choice, because good policy can significantly improve indoor air conditions in both public places and private homes. Smoking bans in various public venues have received broad support, and studies have demonstrated the productivity benefits of good indoor air quality (DEH, 2005).
If there is a genuine shift in public concern about air quality away from city-scale ‘smog’ towards local scale problems, how should government respond, and how should responsibility be divided between state and local government? This paper aims to explore the major issues and possible ways forward.
nonlinear analysis. In the case of externally loaded components, this buckling analysis should take into account the prestressed nature of injection molded components. This has been done by an extension to classical buckling analysis.