Air pollution episodes in New South Wales

Air quality in New South Wales is comparable to other Australian jurisdictions, and air pollution levels are relatively low by world standards.

Ambient levels of air pollutants such as nitrogen dioxide (NO₂), carbon monoxide (CO), sulfur dioxide (SO₂) and lead are consistently below the respective national standards in most areas. 

However, elevated particles (as PM₁₀, and PM_2.5) and ozone (O₃) pollution events can occur in some areas from time to time. These 'air pollution episodes' are characterised by high pollutant levels that may last up to several days, often resulting in concentrations above Australian national standards. These episodes, which can affect your health, are related to a combination of factors including emission sources and weather conditions that cause pollutant build-up.

Particle pollution

PM₁₀ and PM_2.5 pollution can occur due to particles released directly from various sources or particles formed by chemical reactions in the air involving precursor gases. Particle levels above national standards are often associated with dust storms and vegetation fires (such as hazard reduction burns and wildfires). Human activities such as motor vehicles, residential wood heaters, mining, industry, power generation and non-road vehicles and equipment also contribute.

Recent and ongoing research continues to expand the evidence base on the composition and sources of particle pollution in New South Wales.

Ozone pollution

Ground-level ozone is a secondary photochemical pollutant formed when precursor pollutants, oxides of nitrogen (NO_x) and volatile organic compounds (VOCs) react in sunlight. Elevated ozone levels in the Sydney Greater Metropolitan Region (including the Illawarra, Central Coast and Lower Hunter regions) can result from local NO_x and VOC emissions, or those being transported from other regions.

South-west and north-west Sydney generally experience more frequent days with ozone levels above the national standards. These typically occur during the warmer months, with peak levels coinciding with high temperature days and the influence of sea breezes. 

Recent research that consolidates and expands knowledge on ozone pollution in New South Wales includes:

• Ozone State of Knowledge Study
• Summarising climate and air quality (ozone) data on self-organising maps: a Sydney case study
• Visualising the relationships between synoptic circulation type and air quality in Sydney, a subtropical coastal‐basin environment

Episode analysis reports

You can see analysis reports related to selected air pollution episodes in New South Wales. We publish episode analysis on an ongoing basis.