The RAC Air Health Monitor is the biggest air sensor network in Australia. Powered by hundreds of sensors, showing hour-by-hour changes to the air quality across the metropolitan area. Helping move towards a future of cleaner transport.

What are we measuring, and how?

What we monitor

The RAC Air Health Monitor measures particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO2).

The particles that make up PM can be emitted from a range of sources, including vehicles, building and industry, 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 NO2 in built-up areas. NO2 can cause serious health conditions, including irritation and inflammation of the respiratory system. Some studies suggest there may be links between NO2 exposure and heart problems, diabetes, adverse birth outcomes, and cancer.

How we monitor

We use an interactive model which blends air quality data from our sensor network with other sources, including near real time traffic data from Main Roads WA, and motor vehicle emissions modelling from Copert Australia.

The model also includes emissions data from the Department of Climate Change, Energy, the Environment and Water’s National Pollutant Inventory (NPI) database.

RAC Air Health Monitor index classification:

Category PM2.5 (ug/m3) PM10 (ug/m3) NO2 (ppb)
Good (better than WHO threshold) 0-4 0-14 0-9
Moderate (not ideal, but better than WHO 24-hr average threshold) 5-14 15-44 10-24
Unhealthy for sensitive groups (worse than WHO threshold) 15-24 45-49 25-79
Unhealthy 25-49 50-99 80-119
Very unhealthy 50-99 100-199 120-179
Hazardous 100-299 200-599 180-239
Extreme 300+ 600+ 240+

The ratings for particles (PM10 and PM2.5) and for nitrogen dioxide (NO2) are based on hourly real time data. Concentrations are measured as ug/m3 (micrograms per cubic metre) or ppb (parts per billion).

Find out more about how our air is rated.

What to do when the air quality is poor?

The Western Australia Department of Health endorses the following health directions on the DWER page during periods where the PM2.5 concentrations are elevated. Please follow directions from emergency services and advice from your doctor at all times.


Actions for cleaner and healthier air

Learn what we’re doing for cleaner and healthier air and what actions you can take.

Find out more

Air Health Sensor graphic

Biggest network in Australia

200 sensors to be deployed

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Pollutants measured

PM2.5, PM10 and NO2

Map of WA with pin drop on Perth graphic

RAC Air Health Monitor coverage

Over 9,730km2 covered

Frequently asked questions

Powered by

  • Clarity logo
  • Ramboll logo

Local air pollution and health experts led by Professor Gavin Pereira from Curtin School of Population Health, Curtin University as part of the Planning and Transport Research Centre (PATREC) have provided support of the RAC Air Health Monitor through an independent review.

Watch the below video and hear from the team at RAC, Clarity and wider stakeholders who have been involved in the RAC Air Health Monitor so far.



The RAC Air Health Monitor was recognised as the winner of the 2023 Clean Air Society of Australia & New Zealand WA Branch Clean Air Achievement Award.