3.3 Urban air quality
Increased motor vehicle use threatens urban air quality gains
Since the 1980s, urban air quality in NSW has improved significantly. Substantial reductions in the levels of carbon monoxide, nitrogen dioxide, sulfur dioxide and lead have been recorded. Photochemical oxidants (measured as ground-level ozone) and particles with a diameter of 10 micrometres or less (PM10) continue to exceed air quality standards on occasions and are now the pollutants of primary concern for urban air quality.
Motor vehicles are the most significant source of urban air pollution. Technological improvements have reduced emissions from new vehicles, but in the Sydney region in particular these gains may be offset by a continuing growth in the use of vehicles.
Status of Indicator
3.7 Concentrations of carbon monoxide
Concentrations of carbon monoxide have been declining and even in the Sydney CBD no exceedences of the AAQ NEPM standard have been recorded since 1998.
3.8 Concentrations of ozone
Under certain meteorological conditions the ozone standards are exceeded. The data shows no clear trend.
3.9 Concentrations of lead
Ambient levels of lead in the Sydney region are less than 20% of the AAQ NEPM standard and are now frequently below detection limits.
3.10 Concentrations of nitrogen dioxide
Concentrations over the last eight years have remained relatively stable. During this period the AAQ NEPM standard was only exceeded twice.
3.11 Concentrations of sulfur dioxide
Peak 1-hour concentrations in Sydney are now less than 25% of the standard with the Hunter peak levels slightly higher. The Illawarra region data show higher peak concentrations because of the influence of local point sources.
3.12 Concentrations of particles (PM10)
Peak concentrations of particles and exceedences of the particle standard are dominated by bushfire events, as in 1994 and 2001. The strong influence of these exceptional events makes it difficult to discern any trend in the data.
Importance of the issue
Air pollution can be associated with acute health effects such as asthma and angina. Health studies have also shown associations between air pollution and chronic health problems, such as lung cancer, bronchitis and cardiovascular disease, and mortality (Dockery et al. 1993; Pope et al. 2002). In 1998 the National Environment Protection Council (NEPC) set ambient air quality standards to assist in safeguarding the public from such impacts. The National Environment Protection Measure for Ambient Air Quality (AAQ NEPM) sets standards for six pollutants: ozone, particles, carbon monoxide, sulfur dioxide, nitrogen dioxide and lead (NEPC 1998). Apart from their impact on human health, some of these pollutants can also damage vegetation and the built environment.
Short-term exposure to elevated concentrations of ozone for up to several hours can cause respiratory irritation and changes in lung function, particularly for those suffering a respiratory illness (WHO 1998). Associations have also been found between elevated concentrations of ozone and increased hospital admissions (Schwartz 1996; Ponce de Leon 1996; Morgan et al. 1998a) and higher mortality rates (Anderson et al. 1996; Morgan et al. 1998b).
Ozone is a secondary pollutant formed by the reaction of oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in warm sunny conditions. Motor vehicles are significant sources of both these precursor pollutants. In the Sydney region motor vehicles are responsible for about 79% of NOx and 44% of anthropogenic VOCs, with industry, domestic and commercial activities responsible for the remainder of anthropogenic emissions (EPA data, as at 2002). There are also significant biogenic emissions of VOCs from vegetation.
The AAQ NEPM sets two standards for ozone: a 1-hour standard of 0.10 parts per million (ppm) and a 4-hour standard of 0.08 ppm. Figure 3.4 shows exceedences of the AAQ NEPM standards for ozone in the Greater Metropolitan Region (GMR: Sydney, Illawarra and the lower Hunter) between 1994 and 2001.
In the Sydney and Illawarra regions ozone concentrations can be expected to exceed the AAQ NEPM standards on days that have suitable meteorological conditions. In Sydney, exceedences of the 4-hour standard occurred on 21 days in 1997 and 2001 (Figure 3.4). Exceedences are much less frequent in the Illawarra, occurring up to seven days per year. In the lower Hunter region there has been only one exceedence of the 1-hour standard, and four exceedences of the 4-hour standard since 1994.
Figure 3.4: Exceedences of the 1-hour and 4-hour standards for ozone, GMR
Source EPA data, as at 2002
Figure 3.5 shows the maximum (or highest) recorded concentrations of ozone in the GMR, together with the 95th percentiles, which is the value that exceeds all but the highest 5% of the values. In the Sydney region, the maximum ozone concentrations have been as high as 175% of the AAQ NEPM standards, while in the Illawarra region they are generally about 20 to 50% above the standards. Maximum concentrations in the lower Hunter have generally been below the NEPM standard, except in 1997. Like the number of exceedences in Figure 3.4, the maximum concentrations vary greatly from year to year depending on meteorological conditions. As a result, maximums are not necessarily the best indicator of the long-term trends. The 95th percentile is less influenced by the more extreme events and probably provides a better indication of the underlying trend in the data. Figure 3.5 shows little change in the 95th percentiles in the GMR over the last eight years.
Figure 3.5: Annual maximum and 95th percentile values for concentrations of ozone, GMR
Source: EPA data, as at 2002
Research into the impact of air pollutants on human health is a developing area. Epidemiological studies have found associations between particle pollution and health effects, although the mechanisms by which particles affect human health have not been clearly established. Studies of particles smaller than 10 micrometres (µm) in diameter (known as 'PM10') suggest an increase of just 10 micrograms/cubic metre (µg/m3) over a 24-hour period can cause a 1% increase in daily mortality (Ostro 1993; Dockery & Pope 1994; Morgan et al. 1998b). Other adverse health effects have also been correlated with higher levels of these particles. For example, Lewis et al. 1998 demonstrated a strong link between chest colds in children and PM10 in the Hunter and Illawarra, and long-term exposure to air pollution, including particles, has been linked with reduced life expectancy (Dockery et al. 1993; Pope et al. 2002).
Concern is growing about the health risks of finer fractions of particles as these can travel into the lower respiratory tract and lodge in the very small airways of the lungs. This has seen a shift in interest from PM10 to PM2.5 (particles smaller than 2.5 (m in diameter) and even PM1 and sub-micrometre particles. Other characteristics, such as the constituents of the particles themselves, are also believed to play a role in health impacts. These characteristics can vary greatly between sources, regions and seasons. This may have implications for the health effects and the applicability of standards. The AAQ NEPM currently uses PM10 as its standard for particles (see Figure 3.6 and Figure 3.7) but has recently been amended to introduce reporting of PM2.5.
Bushfires are responsible for most of the occasions when high levels of particle pollution are recorded. This is particularly evident in the data shown in Figure 3.6 and Figure 3.7 for 1994 and 2001 when severe bushfires burned throughout the greater Sydney area. The maximum value recorded overall was three times the standard in Sydney in late 2001. For the non-bushfire period the maximum value for 2001 was approximately 83% of the standard.
Figure 3.6: Exceedences of the 24-hour standard for particles (PM10), GMR
Source: EPA data, as at 2002
Figure 3.7: Annual maximum and 95th percentile values for particles, GMR
Source: EPA data, as at 2002
In the absence of bushfires, hazard reduction burning, domestic wood heating and diesel vehicles become the major sources of particles in urban areas. In regional centres exceedences of the standard can also occur as a result of bushfires as well as burning for hazard reduction or agricultural purposes. Severe bushfires in 2002 have also resulted in high levels of particles in the GMR.
Occasionally, widespread dust storms can also result in extreme particle levels. During one of these episodes in November 2002, the AAQ NEPM standard was exceeded in all regions where monitoring was carried out. Levels ranged from about 120% of the standard at Tamworth to about three times the standard at Wagga Wagga and five times the standard at Bathurst. Levels of about 160% of the standard were recorded in Sydney, the Illawarra, lower Hunter and Albury.
The AAQ NEPM includes four other pollutants because of their potential impact on human health: carbon monoxide, which affects the uptake of oxygen; nitrogen dioxide and sulfur dioxide, which act as respiratory irritants; and lead, which can impair intellectual development in children. Levels of these four pollutants in the GMR are generally well below the AAQ NEPM standards. Motor vehicles are the dominant source of carbon monoxide and nitrogen dioxide.
Levels of carbon monoxide have fallen over the last two decades as a result of changes to motor vehicle technology. Even in the Sydney CBD, where traffic densities are high, recent measurements indicate that carbon monoxide levels are now generally below the AAQ NEPM standard of 9 ppm for an 8-hour average.
Levels of nitrogen dioxide are also strongly influenced by motor vehicle emissions and under particular meteorological conditions elevated levels can occur. Exceedences of the AAQ NEPM standard of 0.12 ppm for a 1-hour average were commonly observed in the winter months during the early 1980s. Now exceedences are rare and for the last three years the highest value recorded in the Sydney region was 0.08 ppm. Over this period, maximum concentrations of 0.07 and 0.06 ppm were observed in the Illawarra and lower Hunter regions respectively.
Sulfur dioxide in the GMR mainly originates from industries such as metal processing, oil refining and coal-fired power generation. Overall, levels of sulfur dioxide are low with maximum hourly ambient concentrations in the Sydney region less than 25% of the AAQ NEPM standard of 0.20 ppm. Higher levels are observed in the more industrialised Illawarra and lower Hunter regions as a result of the influence of point sources. The GMR recorded no exceedences between 1994 and 2001.
Changes to fuel formulation have brought marked reductions in the levels of lead in the atmosphere. Annual averages in the Sydney region are now less than 20% of the AAQ NEPM standard of 0.5 µg/m3. With a complete ban on lead in petrol now in force, the primary source of lead in air at the regional scale has been eliminated. Using current methodology, ambient levels of lead are now frequently below detection limits and it is envisaged that in the near future, there will no longer be a need to routinely monitor for lead in the atmosphere.
Response to the issue
Motor vehicles are significant contributors to airborne levels of photochemical smog, carbon monoxide, nitrogen dioxide and particles, as well as some air toxics (see Atmosphere 3.4). Action for Air, the NSW Government's 25-year air quality management plan for Sydney, the Illawarra and lower Hunter regions, identifies the reduction of motor vehicle emissions as the highest priority strategy to meet national air quality standards and goals (NSW Government 1998). The key Action for Air strategies are:
- improving vehicle technology to reduce emissions
- improving transport choice
- reducing private vehicle travel, measured as vehicle kilometres travelled (VKT)
- integrating urban infrastructure and public transport.
Other Action for Air strategies include promotion of cleaner businesses and homes; managing the impact of open burning; and convening a broadly based public forum every three years to encourage public input on air quality trends and strategies.
Complementing Action for Air is the Government's Action for Transport 2010 (see Human Settlement 2.4), which sets out a 10-year plan for expansion and improvement to the region's public transport services.
Improving fuel quality can make a significant contribution to reducing the impact of emissions from motor vehicles. The Commonwealth Fuel Quality Standards Act 2000 is setting new standards for cleaner fuel. Since January 2003, the sulfur content of diesel fuel has been limited to 500 ppm, reducing to 50 ppm by 2006. For petrol, lead fuel has been phased out and a 500 ppm limit on sulfur has applied since January 2002. By 2005, this will need to fall to 150 ppm.
At the same time, new national emission standards for both petrol and diesel vehicles have been set. Between 2002 and 2006, all new vehicles are being required to comply with increasingly stringent standards (see Atmosphere 3.4).
These combined changes are forecast to reduce emissions over time as older vehicles are replaced. Between 2000 and 2020, total hydrocarbon emissions are projected to fall by 26%, oxides of nitrogen by 71%, carbon monoxide by 75% and particles by 35%. Lead and sulfur emissions are also forecast to fall dramatically: 93% and 84%, respectively. Emissions of air toxics, such as benzene, are expected to fall by between 50 and 70%. These projections assume a 32% increase in total VKT (Environment Australia 2000). However, based on recent experience, this may be an under-estimate.
The NEPC has introduced a National Environment Protection Measure for Diesel Vehicle Emissions. The Diesel NEPM provides guidelines for programs to reduce emissions from this growing sector of the vehicle fleet. NSW has commenced a test and repair program for State Transit Authority diesel buses; enhanced the Smoky Vehicle Enforcement Program to allow offenders to be reported via the internet; and is working with the private trucking sector to develop maintenance regimes which ensure vehicles meet in-service emission standards.
The NSW Government announced its Cleaner Vehicles Action Plan in November 2001. The package of initiatives aims to improve air quality in NSW by reducing fuel consumption, dependence on oil, and greenhouse gas emissions through development of the market for cleaner new motor vehicles. The key elements of the plan are:
- environmental performance benchmarks for new light vehicles using emission and fuel efficiency criteria
- consideration of the use of stamp duty as an incentive to encourage purchase of cleaner new cars
- greening the NSW Government fleet, including purchasing cleaner models
- development of a consumer green guide for new cars and light trucks
- a voluntary clean fleet program to recognise fleet operators using environment-friendly practices.
In 1998, NSW introduced load-based licensing for industrial premises. Industry has responded well to the scheme, which provides an economic incentive to improve environmental performance by linking company licence fees to the type and level of pollutants produced. As emissions from large industries decrease relative to other sources, small industrial and commercial activities are being encouraged to adopt cleaner production practices. A feature of the NSW Government's 2001 Environment Statement, Action for the Environment, was the $5 million earmarked for expansion of the EPA's Cleaner Industry Program over three years. The funding will support new technology and involve the EPA working in partnership with business sectors to identify problems and prepare cleaner production plans.
Action for the Environment also included establishment of the Clean Air Fund with $6 million provided over three years through the Environmental Trust. This initiative includes funding for programs to reduce emissions from smaller sources. In 2002–03 up to $750,000 was available for grants to local councils to assist in reducing emissions from local industrial, commercial and construction activities.
Since Action for Air was released in 1998, tighter emission standards have been introduced for new wood heaters and the Protection of the Environment Operations Act 1997 gives local councils the power to take action against people whose solid fuel heaters smoke excessively. The EPA launched a woodsmoke website in 2001 to provide information on how to minimise the impact of wood heaters on winter air quality.
The Woodsmoke Reduction Program from March–September 2002 was a joint initiative between the EPA and six regional councils: Armidale, Blue Mountains, Cooma, Lithgow, Orange and Tumut. The program, funded by the Environmental Trust through the Clean Air Fund, aimed to help these communities switch from wood and coal to cleaner forms of heating. The program had three components: cash incentives for updating to cleaner appliances; education on cleaner heating operation; and enforcement through smoke patrols and follow-up actions. As a result of the program, 744 sub-standard wood heaters were replaced.
NSW councils are committed to the Sustainable Energy Development Authority's Energy Smart Homes Program, which is designed to ensure all new homes meet minimum energy-efficiency requirements. Forty-four councils, representing 75% of NSW residential development applications, are actively implementing an Energy Smart Homes Policy (see Human Settlement 2.3).
Managing open burning
Open burning is a significant source of particle pollution. Councils are able to regulate the level of open burning in their municipality under the Protection of the Environment Operations (Control of Burning) Regulation 2000. The Regulation bans backyard burning in urban areas and restricts it to appropriate levels in rural areas. The Regulation also prohibits burning in the open of certain items, such as coated wire and tyres, and phases out the use of incinerators in home units. The Regulation does not cover hazard reduction burning carried out under the Rural Fires Act 1997.
The EPA has the power to ban all burning on days when conditions are likely to cause elevated levels of particles. However, strategically important hazard reduction burns can be specifically exempted following consultation between the EPA and the Rural Fire Service. The NSW Bush Fire Coordinating Committee has issued the guidelines, Managing Smoke During Prescribed Burning, for use by bushfire management committees, land managers and fire-fighting authorities to help minimise the adverse effects of smoke from hazard reduction burning in smoke-sensitive areas.
Reviewing, monitoring and reporting air quality
The community has become increasingly aware of air quality issues and frequently seeks timely access to air quality data. In addition to its twice-daily regional pollution index (RPI), the EPA website provides a summary of air quality for the previous 24 hours for all sites in its monitoring network. Historical RPI data and quarterly air quality monitoring reports, which report monthly statistics for all sites and pollutants, are also available on the site.
The first Action for Air public forum in late 2001 encouraged public input on air quality trends and strategies. A broad range of community, government and industry groups were encouraged to identify emerging issues, new technologies and possible solutions.
NSW also collects data for the National Pollutant Inventory (NPI). This provides information from a broad range of diffuse and industrial point sources on emissions to air, land and water. NPI data is available to the community on the internet.
In the fourth year of reporting (2001–02), 627 NSW facilities submitted an NPI emissions report against the full list of 90 NPI substances. This means that the NPI is now able to provide a better understanding of the relative environmental impact of industrial, commercial and domestic activities.
With the NPI dataset becoming robust, the EPA is beginning to use the NPI to focus and develop its environmental policies and programs and apply regulatory effort to the highest priority emitters.
Effectiveness of responses
Air quality in the GMR has been steadily improving since the 1980s and the news on some pollutants is good. There has been a dramatic improvement in ambient levels of carbon monoxide and lead; nitrogen dioxide levels are below the national standard and sulfur dioxide concentrations well below it.
The data in this report are for the period 1994 to 2001, a time when the air quality monitoring network was reasonably stable. While there is no discernible trend in ambient levels of ozone, achievement of the national 1- and 4-hour standards is likely to be a significant challenge. Large reductions in emissions of the precursor pollutants, oxides of nitrogen and volatile organic compounds, will be required to consistently meet the AAQ NEPM standards for ozone in the future.
The highest levels of particle pollution (PM10) and most exceedences of the relevant standard are associated with bushfires, which are effectively an uncontrollable source. Other sources include hazard reduction burning, domestic wood heaters and diesel vehicles and programs are in place to address emissions from these areas. In the absence of bushfires, levels are generally within the standard. However, given the increasing concern about the health impacts of particles, continued action is required.
Results from the Woodsmoke Reduction Program indicate the program has been very successful at improving urban air quality in regional towns. A total of 744 wood heaters have been scrapped leading to an estimated permanent annual reduction in particle emissions of 22 tonnes. A community survey at the end of 2002 indicated that 39% of local residents who were aware of the program claim to operate their wood heaters more efficiently now and 34% of residents in participating towns understand that reducing or eliminating the use of solid fuel heaters is one way to improve local air quality.
A strong regulatory regime in NSW over a substantial period of time has effectively reduced and minimised point sources of air pollution. Diffuse and mobile sources are now the major sources of emissions and causes of poor urban air quality. In the last three years the NSW Government and local government have initiated a range of programs, policy and legislative tools to reduce these emission sources, although it is likely to be some time before further improvements in urban air quality can be realised.
Diffuse and mobile sources have been identified as the major contributors to urban air quality. This means that meeting air quality standards and goals will require a wide range of strategies.
Governments need to continue to pursue the integration of land-use and transport planning. There will need to be a continued focus on cleaner vehicles and encouragement of vehicles which use cleaner technology. Governments should also continue to expand and improve public transport, and pedestrian and cycling facilities and examine and carry out strategies to reduce VKT (see Human Settlement 2.4).
Individuals can check their wood heaters comply with relevant standards and are being used correctly. Cleaner heating alternatives can also be considered. Industry can continue to improve its environmental performance by using cleaner production processes in partnership with government.
2.1 Population and settlement patterns
3.4 Air toxics