SoE 2006 > Atmosphere > 3.3 Air quality

3.3 Air quality

Concentrations of sulfur dioxide, carbon monoxide, lead and nitrogen dioxide no longer trigger metropolitan air quality concerns. However, particles and ozone remain a challenge, particularly in the metropolitan area and in some rural locations for particles only.

Overall, air quality in the lower Hunter, Sydney and Illawarra regions (GMR₂) has been steadily improving since the 1980s. In 1998 ambient air quality standards and goals for six pollutants were set in the National Environment Protection Measure for Ambient Air Quality (AAQ NEPM). Concentrations of carbon monoxide, lead and nitrogen dioxide are below their national standards, and sulfur dioxide concentrations are well below its national standard. Currently some exceedences of national standards (with associated goals to be achieved by 2008) occur for ozone and occur periodically for airborne particles.

Urban air pollution arises from emissions by major industry, motor vehicles, commercial operations, and leaking pipes and tanks, as well as from domestic activities such as using solid-fuel heaters. Extreme events such as bushfires and dust storms are the main causes of particle exceedences in GMR₂.

In rural areas the pollutant of primary concern is airborne particulate matter. Air quality standards for particles can be exceeded due to agricultural and hazard-reduction burning, bushfires, the use of solid-fuel heaters, and dust storms.

There is community concern about localised exposure to pollutants near particular sources such as industry, major roads, and road tunnels.

The NSW Government's 25-year air quality management plan, Action for Air, addresses all major sources of air pollution.

NSW indicators

Introduction

Air pollution can cause a wide range of health symptoms, from coughing, wheezing and shortness of breath, to more serious impacts for those with pre-existing respiratory and cardiac conditions, such as asthma attacks, hospital admission and premature death. It has been estimated that air pollution from motor vehicles alone accounts for more than 500 early deaths in the Sydney Region per annum and over 1000 hospital admissions (BTRE 2005). Exposure to high concentrations of air pollution over many years is associated with reduced life expectancy and increased incidence of lung cancer (Pope et al. 2002; Nafstad et al. 2004). The health costs of ambient air pollution in the greater metropolitan region (GMR₂) have been estiamted to be between $1.0 billion and $8.4 billion per annum (DEC 2005). In Sydney, the health costs of motor-vehicle emissions alone are estimated to be between $600 million and $1.5 billion per annum (BTRE 2005). Apart from their impact on human health, some air pollutants can also damage flora, fauna and the built environment.

In 1998 the National Environment Protection Council (NEPC) set ambient air quality standards and goals for six pollutants in the AAQ NEPM which aim to provide adequate protection for the health of the Australian population. There are five primary pollutants (particles, carbon monoxide, sulfur dioxide, nitrogen dioxide and lead) and one secondary pollutant (ozone) (NEPC 1998). Primary pollutants are those emitted directly from various sources and secondary pollutants are formed by the reactions of other pollutants (although particles and nitrogen dioxide can be either primary or secondary pollutants).

To measure compliance, NSW has a comprehensive air quality monitoring and reporting capability that more than meets the requirements of the AAQ NEPM (see EPA 2001). Governments have committed to achieve these air quality goals by 2008.

The primary emissions of interest arise from both natural processes (biogenic) and a wide range of human activities (anthropogenic). Anthropogenic emissions are usefully categorised by the type of activity, and the NSW Air Emissions Inventory, now being developed by DEC, identifies five main source categories: domestic, commercial, industrial, off-road mobile and on-road mobile.

Current status and trends

Significant contributors to anthropogenic emissions in the Sydney Region include motor vehicles; major industry; household and commercial solvent use; household and commercial fuel combustion; commercial activities, such as motor-vehicle repair shops and service stations; and domestic activities such as lawn mowing and using wood heaters (Figure 3.6). In rural areas, agricultural burning, coal heaters and solid-fuel heaters are the most significant sources of particle emissions. Throughout NSW, bushfires and dust storms also generate significant pollution.

Figure 3.6: Anthropogenic sources of NO_x, VOC and PM₁₀ emissions, Sydney Region 2003

Source: DEC data 2006

Ozone

While ozone in the stratosphere helps protect human health by reducing UV-B radiation at ground level, people exposed to elevated concentrations of ozone for several hours at a time are at increased risk from respiratory irritation and changes in lung function, particularly if they are already suffering a respiratory illness (WHO 1998). Studies have found an association between elevated concentrations of ozone and increased hospital attendances (Jalaludin et al. in press), hospital admissions (Morgan et al. 1998a; Barnett et al. 2005) and higher mortality rates (Morgan et al. 1998b; Bell et al. 2005). Some individuals are sensitive to ozone at low concentrations, and health experts have stated that the safe threshold for ozone exposure is likely to be very low (WHO 2003).

In the lower atmosphere, ozone is formed by the reaction of oxides of nitrogen (NO_x) and volatile organic compounds (VOCs) in warm, sunny conditions. This secondary pollution is a particular issue in NSW for the Sydney Region, where motor vehicles are the most significant source of these precursor pollutants, responsible for about 71% of NO_x and 38% of anthropogenic VOC emissions. Commercial–domestic sources, including aerosols, solvents and industrial surface coatings, are estimated to contribute 49% of anthropogenic VOCs. Major industry contributes about 15% of NO_x and 11% of anthropogenic VOCs (see Figure 3.6). Biogenic emissions within the region are large, but in areas of significant anthropogenic emissions, their contribution is relatively modest.

The AAQ NEPM sets two standards for ozone: a 1-hour standard of 0.10 ppm and a 4-hour standard of 0.08 ppm. The AAQ NEPM sets a goal that by 2008 these standards would be exceeded on no more than one day per year at each monitoring site. NSW would not currently meet these goals. Figure 3.7 shows exceedences of the AAQ NEPM standards for ozone between 1994 and 2005 in GMR₂.

In Sydney in the years 1994 to 2005, the number of days on which concentrations exceeded the 4-hour standard ranged from one to 21, with 12 exceedence days in 2005 (Figure 3.7). For the same period, exceedences of the 1-hour standard ranged from zero to 19, with eight exceedence days in 2005. Exceedences are much less frequent in the Illawarra, occurring on up to seven days per year for either standard. The least number of days when exceedences occurred were recorded in the lower Hunter region, with only one exceedence of the 1-hour standard since 1999.

Figure 3.7: Exceedences of the 1-hour and 4-hour AAQ NEPM standards for ozone in GMR₂

Source DEC data 2006

Figure 3.8 shows the maximum recorded concentrations of ozone together with the 95th percentile for each region from 1994 to 2005. There is no clear change in trend as the maximum varies greatly from year to year depending on weather conditions. Maximum concentrations are greatest in Sydney and least in the lower Hunter. The 95th percentile is the value that exceeds all but the highest 5% of the values. It is less influenced by the more extreme weather events and probably provides a better indication of the underlying trend in the data; however, no trend appears to exist.

A 2004 investigation has assessed the potential impact of an increase in population in Sydney on air quality using urban development scenarios of new land-release areas in the north-west and south-west. The modelling showed that changes in emissions arising from any increase in population is a significant pressure on air quality. Catering for desired population growth within Sydney requires a suite of Government policies aimed at reducing emissions.

Figure 3.8: Annual maximum and 95th percentile values for concentrations of ozone, GMR₂

Source: DEC data 2006

Particles

As with ozone pollution, low concentrations of particle pollution can cause health impacts in some individuals (WHO 2003). The concentration, chemical composition and size of the particles are important, and these can vary greatly between sources, regions and seasons. Epidemiological studies have shown associations between particle pollution and health effects. Particulate matter smaller than 10 micrometres (µm) in diameter (PM₁₀) is consistently associated with increased mortality and hospital admissions for people with both heart and lung disease (Morgan et al. 1998a; Morgan et al. 1998b; Simpson 2005a; Simpson 2005b). Research has demonstrated a strong link between chest colds in children and PM₁₀ in the Hunter and Illawarra (Lewis et al. 1998), and long-term exposure to air pollution, including particles, has been linked with reduced life expectancy (Pope et al. 2002). Recent research in Sydney has found that the particles from bushfire smoke are associated with increased hospital admissions for respiratory conditions (Morgan et al. in press).

There is also continuing research on the health risks of finer fractions of particles, such as PM_2.5 (particles up to 2.5 µm in diameter) and PM_1.0 (particles up to 1.0 µm in diameter), as these can travel into the lower respiratory tract and lodge in the very small airways of the lungs.

The approach to air quality standards, both nationally and internationally, continues to focus on particle size. The AAQ NEPM sets a standard for PM₁₀ of 50 micrograms per cubic metre (µg/m³) (1-day average), with a goal of no more than five exceedence days per site per year to allow for natural events such as dust storms and bushfires, to be achieved by 2008. In 2003, the NEPM was amended to include an advisory reporting standard for PM_2.5, recognising that information available at that time was insufficient to set a health-based standard.

The major sources of anthropogenic particle emissions (PM₁₀) in the Sydney Region are industry (37%), the commercial and domestic sectors (35%), and motor vehicles (12%) (see Figure 3.6). Domestic solid-fuel heating makes up a significant proportion of commercial and domestic emissions, and diesel vehicles are the major contributor to motor vehicle emissions. In many rural and regional areas, solid-fuel heaters contribute a greater proportion of particle levels. Emissions from agriculture are also a factor in rural and regional areas.

The national goal for particles (PM₁₀) is generally being met in Sydney, except in years with bushfires or dust storms. Bushfires in 1994 and 2001–03 were responsible for the extremely high concentrations of particle pollution recorded in GMR₂ in those years (Figure 3.9 and Figure 3.10). The number of exceedences varies greatly from year to year as shown by the marked drop in 2004.

In rural areas, exceedences occur from bushfires, hazard-reduction burning, agricultural stubble burning, and the use of solid-fuel heaters. The maximum value recorded in 2003 of 921 µg/m³ occurred during a dust storm.

Figure 3.9: Exceedences of the 24-hour AAQ NEPM standard for particles (PM₁₀) in NSW regions

Source: DEC data 2006

Note: Rural is Albury, Bathurst, Tamworth and Wagga Wagga.

Figure 3.10: Annual maximum and 95th percentile values for particles in NSW regions

Source: DEC data 2006

Notes: Rural (Albury, Bathurst, Tamworth and Wagga Wagga) monitoring commenced in 2002.

Other pollutants

The AAQ NEPM includes four other pollutants because of their potential impact on human health: carbon monoxide, which affects the uptake of oxygen in blood; nitrogen dioxide and sulfur dioxide, which act as respiratory irritants; and lead, which can impair intellectual development in children. Concentrations of these four pollutants in GMR₂ are generally well below the AAQ NEPM standards. Motor vehicles are the dominant source of carbon monoxide. Concentrations of carbon monoxide have fallen over the last two decades as a result of changes to motor vehicle technology. Even in the high-density traffic conditions of the Sydney CBD, recent measurements indicate that carbon monoxide levels do not exceed the AAQ NEPM standard of 9 ppm for an 8-hour average.

Motor vehicles are also the dominant source of nitrogen dioxide, which can occur at elevated concentrations under particular meteorological conditions. 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. Exceedences are now rare, and from 2002 to 2005 the highest 1-hour value recorded in Sydney was 0.09 ppm, which is less than 75% of the standard. Over this period, maximum 1-hour concentrations were less in the Illawarra and lower Hunter regions, with concentrations of 0.07 and 0.05 ppm respectively.

Sulfur dioxide in GMR₂ originates mainly from industries such as metal processing, oil refining and coal-fired power generation. From 1994 to 2005 concentrations of sulfur dioxide were low with no exceedences recorded in GMR₂. Maximum hourly ambient concentrations in Sydney were less than 25% of the AAQ NEPM standard of 0.20 ppm. Higher concentrations are observed in the Illawarra and lower Hunter regions as a result of industrial emissions.

Changes to fuel formulation have brought marked reductions in the concentrations of lead in the atmosphere. Annual averages in Sydney are less than 20% of the AAQ NEPM standard of 0.5 (g/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 concentrations of lead were frequently below detection limits, and routine monitoring of lead ceased in December 2004.

Localised air pollution

Monitoring and reporting under the AAQ NEPM focuses on ambient pollution levels. Localised air quality may differ significantly from regional conditions due to local sources such as industrial or commercial facilities or congested roads. These may result in elevated localised concentrations of air pollution. The NSW Government has undertaken a number of reviews and assessments to assist in managing localised air pollution, such as in and around road tunnels (SESPHU & NSW Health 2003; NSW Health 2003a; NSW Health 2004a; NSW Health 2004b). Ambient air quality monitoring has been conducted at two sites near the Eastern Distributor (RTA 2001) and four sites near the M5 East (RTA 2006). Ambient air quality monitoring stations located near the Cross City Tunnel have also been established (CrossCity Motorway Pty Ltd 2005).

In general, no exceedences of ambient air quality standards associated with emissions from road tunnels have been detected. A study by NSW Health concluded that nitrogen dioxide levels in road tunnels may be of concern for people with asthma travelling in open vehicles (including motorcycles) when transit times are likely to be prolonged. Closing the vehicle windows and vents (and re-circulating air) significantly reduces exposure to all vehicle pollutants (SESPHU & NSW Health 2003).

Response to the issue

Action for Air is the NSW Government's 25-year air quality management plan for GMR₂ (NSW Government 1998). It includes major measures for addressing air quality, such as standards for motor vehicle emissions and fuel quality, licensing systems for industry, the regulation of backyard burning, and measures to reduce emissions from domestic solid-fuel heaters. A public Clean Air Forum is held on Action for Air every three years and an update of air quality management activities under Action for Air was completed in 2006 (DEC 2006). A review of Action for Air is due to be completed in 2007.

The NSW Government's Metropolitan Strategy (DoP 2005) references the national air quality standards and sets out a series of environmental targets. One target is to reduce air emissions and improve compliance with national standards for air quality to protect health. The actions for the 'Transport' and 'Centres and Corridors' strategies (within the Metropolitan Strategy), which aim to improve the existing transport system and increase use of public transport, will contribute to improved air quality in Sydney.

The Metropolitan Strategy also establishes sustainability criteria applicable to proposed new greenfield land-release areas. One of the key criteria relates to environmental protection, and requires that development in land-release areas maintains or improves existing air quality.

Motor vehicle emissions

The Commonwealth Fuel Quality Standards Act 2000 establishes national environment standards for motor vehicle fuels. Vehicle emission standards for new cars are set in the Australian Design Rules, which are enforced nationally under the Commonwealth Motor Vehicle Standards Act 1989.

Significant gains have already been made in reducing emissions from motor vehicles through improvements to Australian fuel and vehicle-emission standards. Stricter standards are progressively being introduced. Despite expected increases in vehicle kilometres travelled (see Human Settlement 2.4), levels of motor vehicle emissions of carbon monoxide, VOCs, NO_x and particles in GMR₂ are forecast to fall by at least 62%, 40%, 55% and 40% respectively from 2002 to 2020 (NSW Government 2003). However, some recent European vehicle testing indicates that such emission reductions may not be fully achieved in real driving conditions, particularly for NO_x (T&E 2006).

The NSW Government has a number of policies addressing motor vehicle emissions. Among the more significant is the regulation of petrol volatility during summer through the Protection of the Environment Operations (Clean Air) Regulation 2002. This Regulation is estimated to reduce motor vehicle VOC emissions in the greater metropolitan area (GMA) (see Human Settlement 2.3) by around 17% over the summer period. This equates to a reduction in VOC emissions of over 2500 tonnes each summer.

NSW is undertaking the Diesel Retrofit Demonstration Project to improve the emissions performance of in-service diesel vehicles by fitting emission reduction devices to their exhausts. Such devices are now being used overseas in reducing particle emissions from diesel vehicles. The trial is designed to assess the feasibility, costs and benefits of implementing a broader diesel retrofit program in NSW.

The Government also addresses motor vehicle pollution by promoting integrated land-use and transport planning and encouraging alternative methods of transport to the motor vehicle. The Government's vision and supporting initiatives for Sydney's land use and transport are outlined in the Metropolitan Strategy (DoP 2005) (see Human Settlement 2.1) and in Action for Air.

Before their construction and operation, all major urban road tunnels require independent assessment by the Department of Planning and approval by the Minister for Planning under new provisions in Part 3A of the Environmental Planning and Assessment Act 1979. These assessments consider a range of factors including air quality and impacts on specific areas. All existing approvals for road tunnels contain emission limits and monitoring requirements to ensure that emissions from tunnel stacks do not cause adverse environmental impacts.

Bus fleet emissions

Under NSW's new bus contract system, older diesel buses will be replaced with new vehicles that comply with international standards (referred to as 'Euro standards') under a seven-year procurement plan, to achieve an average vehicle age of 12 years and a maximum age of 25 years by 2012. The current system of regional individual bus services is being replaced with an integrated network of services supporting cross-regional routes linking key centres. The new bus routes, combined with bus priority lanes on strategic corridors, aim to reduce traffic congestion and promote public transport patronage.

Industry emissions

The Protection of the Environment Operations Act 1997 (POEO Act) established a system for the licensing of major industry. The Clean Air Regulation under the Act provides the framework for managing air pollution from licensed premises, including setting 'never to be exceeded' concentration limits for air pollution. This regulation was updated in 2005 to include tightened controls on industrial emissions, the introduction of controls on VOC emissions, and a requirement for industry to meet the latest standards when replacing or modifying old equipment. To reduce pollution below the level required by the Regulation or licences, load-based licensing commenced in 1999. The scheme introduced additional licence fees for major emitters based on pollution load. However, in general air pollution fees were too low to drive pollution abatement by industry. The fees for emitting pollutants into the air were increased in 2004 by approximately 45% for the State's top 10 emitters, providing them with increased incentive to abate their air emissions.

Commercial and domestic emissions

Under the POEO Act, local councils have the principal responsibility for managing emissions from commercial and domestic premises. The NSW Government is developing capacity-building programs for local government, such as the Air Quality Toolkit.

The Protection of the Environment Operations (Clean Air) Regulation 2002 enables councils to exercise a level of control on burning in the open that is appropriate for local conditions. However, the Regulation exempts the burning of vegetation for agricultural purposes from the controls that might otherwise be imposed on open burning. The adoption of crop stubble management practices that rely less on open burning is expected to reduce particle concentrations in agricultural areas. The Air Quality Toolkit provides guidance to local council officers on promoting good practice in relation to agricultural stubble burning.

Emissions from domestic solid-fuel heaters have been the subject of strong NSW education and replacement programs in partnership with local councils and are also being addressed through national initiatives to improve solid-fuel heater design standards. NSW has introduced a new offence under the POEO Act relating to excessive smoke emissions from residential chimneys. Local councils have planning powers to manage or restrict the installation of domestic solid-fuel heaters.

From 2002–04, the NSW Government, in cooperation with local councils, ran a Woodsmoke Reduction Program in regional areas of NSW. The program included a cash incentive scheme for replacing older solid-fuel heaters with cleaner heating alternatives, as well as an education campaign about the better operation of heaters and an enforcement program targeting excessively smoky chimneys. The program has succeeded in removing an estimated 61 tonnes of fine particulate pollution annually from the airsheds of participating communities. Some councils are conducting ongoing education utilising tools provided through the program.

To control the emission of the precursor pollutants (NO_x and VOCs) leading to ozone production, new policies targeting the commercial and domestic sectors are being developed by the NSW Government. These include policies to increase the availability and use of cleaner small engines (such as lawn mowers, hand-held garden equipment and outboard motors), and strategies to reduce petrol-vapour emissions from service stations in the GMA.

Health warnings

In November 2004, DEC and NSW Health jointly introduced a system of health alerts for predicted high-pollution days, which advises people on taking steps to reduce the adverse effects on their health. Health alerts are released to the public via the media, a free-call line, and the NSW Health and DEC websites. Seven alerts had been issued to the end of 2005.

Future directions

Ambient concentrations of sulfur dioxide, carbon monoxide, lead and nitrogen dioxide are well controlled in NSW. However ozone concentrations currently exceed the national air quality goals that are to be achieved by 2008. Modelling work undertaken by DEC shows that unless further controls are implemented, ozone concentrations will continue to exceed these goals into the 2020s, despite the expected significant reductions of NO_x and VOC emissions resulting from improved standards for fuel and vehicles (NSW Government 2003). This work emphasises the need for ongoing reductions from all major sources of ozone precursors, and these will be considered as part of the review of Action for Air. Particle emissions in the Sydney Region will also need to be reduced because concentrations occasionally approach the national health standard for PM_10, even in the absence of natural events such as bushfires and dust storms. In some rural and regional areas, exceedences of the national standard for PM₁₀ suggest the need for better management of agricultural burning and emissions from solid-fuel heaters.

The forecast growth in NSW's population and in private and commercial vehicle travel will require a renewed focus on motor vehicle emissions. A strong emphasis on integrated land use and transport planning, including public transport planning, is needed. An increased uptake of hybrid vehicle technologies (Australian Government 2005b) will also help to achieve reductions in motor vehicle emissions.

The level of understanding of the health impacts of air pollution is also improving. A review of the AAQ NEPM commenced in 2005 with a decision on whether to revise the standards likely in 2008. If revised standards are introduced, they may require further efforts to reduce emissions.

It is likely that weather patterns for NSW will continue to change due to global climate change (see Atmosphere 3.1), with associated changes to air quality in metropolitan and regional areas. Increased temperatures would result in a longer season for elevated concentrations of ozone. Changes to rainfall and temperature may increase the frequency of bushfire-related pollution events, and shifts in weather patterns may increase the number of calm days, resulting in more days of elevated particle concentrations (CSIRO 2003b).