Traffic-related emissions have been steadily declining across Perth over the past three years, according to the 2025 RAC Air Health Monitor report.
The award-winning RAC Air Health Monitor is the largest air quality monitoring network in the country, with more than 200 sensors located throughout the Perth metropolitan area.
RAC Group Executive Social and Community Impact Terry Durant said the findings showed encouraging progress, while also highlighting opportunities to improve.
"We are lucky to live in one of the most beautiful cities in the world, with clear skies and fresh air, but we should never take that for granted. The RAC Air Health Monitor allows us to keep an eye on air quality conditions," Ms Durant said.
"While we’re moving in the right direction, there is still more to do to protect the quality of the air we all share, particularly as our city continues to grow."
“While Perth’s air quality generally meets Australian standards, most monitoring locations remain above the more stringent health-based guidelines established by the World Health Organisation (WHO).”
“This highlights an important gap between meeting regulatory standards, and the levels of air pollution that would protect our entire community, including vulnerable groups like children, older Australians and people with heart or lung conditions.”
The sensors pick up three types of air pollutants – nitrogen dioxide (NO2), PM2.5 and PM10. Vehicle emissions are a major source of NO2 in built-up areas.
Since 2023, annual average NO2 concentrations have declined by almost 16 per cent, while fine particle pollution (PM2.5) has decreased by more than 17 per cent. Schools recorded some of the strongest improvements, with average NO2 amounts falling by almost 27 per cent.
The report also includes the first full year of black carbon monitoring, with findings showing around 80 per cent was linked to fossil fuels. Black carbon, commonly known as soot, is a harmful component of PM2.5 pollution often associated with vehicle emissions.
Sensors located near major roads and highways recorded higher short-term exposures to NO2, with just under half of the daily averages still higher than the WHO guidelines.
"These findings show why we need a coordinated statewide approach to air quality management that targets action where it is needed most," Ms Durant said.
"RAC continues to advocate for the WA Government to lead the development of an effective, contemporary air quality plan for the state."
“This is crucial in enabling and encouraging governments to prioritise transport and planning policies and investments that reduce vehicle emissions.”
BACKGROUND
About the RAC Air Health Monitor
The RAC Air Health Monitor was launched in 2022 and consists of high-tech Clarity sensors placed in strategic locations around the Perth metropolitan area, from Dawesville to Yanchep and east to Wooroloo.
The sensor data is then fed into an interactive Ramboll Shair online platform, which shows the quality of Perth’s air, in near-real time.
Learn more: RAC Air Health Monitor
What pollutants are measured by the RAC Air Health Monitor?
The RAC Air Health Monitor uses an interactive model which blends air quality data from the sensor network with other sources, including satellites and traffic monitoring services.
The RAC Air Health Monitor measures Particulate Matter (PM2.5 and PM10) and nitrogen dioxide (NO2).
PM is a measurement of microscopic particles. PM10 refers to particulate matter 10 micrometres or less in diameter, while PM2.5 is 2.5 micrometres or less in diameter. PM can be a mixture of many sources, including vehicle emissions, building and industry emissions, and dust. PM can be inhaled into the lungs and sometimes enter the bloodstream, impacting cardiovascular and respiratory systems.
Transport is a major source of nitrogen dioxide (NO2) in built-up areas. NO2 impacts the respiratory system and can cause bronchitis in children with asthma, reduce lung function, cancer and other health and environmental implications.