Roads and Maritime Services is committed to improving air quality by effectively managing the NSW roads and traffic system. As our population continues to grow, we recognise the importance of delivering transport infrastructure for our customers and local communities that meets high air quality standards.
Sydney's air quality
Sydney’s air quality is good by national and international standards.
Air quality in Sydney is good by national and international standards. For example, in a 2011 study of 30 major cities worldwide prepared by Environment Canada, Sydney ranked second only to Vancouver in a comparison of annual average particulate matter less than 2.5 microns (PM)2.5.
Please note: Caution must be taken when comparing air quality in urban areas. Differences in monitoring equipment, in the rationale behind placement of stations and in the number of stations can influence the comparability of concentrations from different urban areas.
To find out more about how Sydney's air quality compares, see:
- Environment Canada - International Comparison of Urban Air Quality Indicators Data
- World Health Organisation - Exposure to ambient air pollution
Motor vehicles as a source of air pollution
Motor vehicles are a significant but declining source of air pollution.
Motor vehicles are a major source of human generated air pollution in Sydney, contributing 62 per cent of oxides of nitrogen (NOx) emissions, 24 per cent of volatile organic compound (VOC) emissions, and 14 per cent of PM2.5 emissions during 2008 (Figure E2; EPA, 2012).
To find out more about motor vehicle air pollution, see Reducing emissions when we drive.
To find out more about air emissions in your community, see the Environmental Protection Agency website.
Ozone is a major component of photochemical smog. It is formed in the lower atmosphere when a number of ‘precursor’ compounds - mainly oxides of nitrogen (NOx) and volatile organic compounds (VOCs) - react in warm, sunny conditions. Peak ozone levels in Sydney are therefore typically observed between November and March.
Particulate matter (PM) in the air can come directly from natural sources such as bushfires and dust storms, and also from human activities such as wood burning, quarrying and mining, motor vehicle use and industrial processes. Particle pollution is evident as the brown haze sometimes seen in the cooler months of the year.
To find out more about common air pollutants – including standards and sources – see the EPA publication Substance Information.
Newer vehicles produce significantly less emissions than older vehicles. Increasingly better fuels, improved technology and stringent emission standards have contributed to this improvement, which is likely to continue in the future. For example:
- Cars built since 2013 emit three per cent of the oxides of nitrogen than vehicles built in 1976.
- Diesel trucks built from 2013 emit eight per cent of the particles emitted by vehicles built in 1996.
As a result of the increasingly stringent emission standards and improvements in fuel quality, total exhaust emissions from motor vehicles have decreased over the past two decades, despite the increase in vehicles. They are expected to continue to fall (Figure E5), despite projected increases in the number of vehicles in use and the number of kilometres driven.
To find out more about vehicle emission standards, see Emission standards.
Reducing emissions when we drive
Roads and Maritime Services, along with other agencies, has done extensive research to improve vehicle emissions, and has developed and implemented a range of initiatives to reduce the impact of vehicle emissions on the air quality in NSW:
- Helping to reduce emissions when driving your petrol vehicle
- Helping to reduce emissions when driving your diesel vehicle
Managing air quality in and around tunnels
Roads and Maritime adheres to strict conditions set down by the NSW Department of Planning and Environment for the maximum allowable presence of vehicle emissions in the air both in and outside its tunnels.
Air quality monitors in and outside the tunnels constantly measure the presence of carbon monoxide, nitrogen dioxide, fine particles and visibility levels. For more information on how Roads and Maritime manages air quality in and around tunnels, see Sydney road tunnels.
In-tunnel Air Quality (Nitrogen Dioxide) Policy
In January 2016, the NSW Government introduced a formal policy for emissions compliance in new tunnel projects to protect the health and safety of tunnel users.
Find out more information on the In-tunnel Air Quality (Nitrogen Dioxide) Policy.
Assessing air quality impacts from surface roads
Recognising the contribution of motor vehicles to air pollution, Roads and Maritime developed the Tool for Roadside Air Quality (TRAQ). TRAQ assesses the potential air quality impacts and greenhouse gas emissions from vehicles using a new or existing roadway.
Find out more information about Assessing air quality impacts from surface roads.
To stay alert, keep the fresh air flowing while you drive
We all know that setting the ventilation system (air-conditioning) to recirculate can help heat and cool your vehicle, as well as minimise the dust and unpleasant odours. What you mightn’t know is that over time, carbon dioxide levels increase. This means the air inside your car is becoming “stale”, which could lead to increased fatigue and a decline in your ability to concentrate.
To avoid this, you should not leave your ventilation system on recirculate for extended periods of time. To stay alert, keep the fresh air flowing by opening your windows or changing the ventilation system settings every hour or so.