Sulfur dioxide (SO2) is a gas. Breathing it in can irritate your nose, throat and lungs.

Sulfur dioxide is a common air pollutant. In Victoria, sulfur dioxide levels are usually low. We measure sulfur dioxide at some of our air monitoring sites.

Sources of sulfur dioxide

Burning materials with a high sulfur content produces sulfur dioxide. In Victoria, the most common sources of sulfur dioxide include:

Health effects of sulfur dioxide

Breathing in sulfur dioxide can impact your health. When levels are high, you can experience symptoms shortly after you breathe it in.

Symptoms include wheezing, coughing and shortness of breath. People with lung conditions like asthma are most affected by high levels of sulfur dioxide.


Infographic showing the health impacts of Sulfur Dioxide.

Sulfur dioxide on EPA AirWatch

We show sulfur dioxide data on EPA AirWatch using air quality categories.

Air quality category Sulfur dioxide averaged over 1 hour (parts per billion)
Good   Less than 100
Fair   100–200
Poor   200–300
Very poor   300–600
Extremely poor   More than 600

Current standards for sulfur dioxide

We compare our sulfur dioxide data to national air quality standards.

The 24 hour national sulfur dioxide standard has been adopted into the Environment Reference Standard. Victoria has adopted a more stringent 1-hour sulfur dioxide standard in the Environment Reference Standard, bringing forward the 2025 national standard.

National standard, in parts per million (and per billion) Averaging time
0.1 ppm (100 ppb) 1 hour
0.075 ppm (75 ppb) from 2025 1 hour
0.02 ppm (20 ppb) 24 hours
Environment Reference Standard  
0.075 ppm (75 ppb) 1 hour
 0.02 ppm (20 ppb) 24 hours

Read more about air quality

Carbon monoxide in the air

Nitrogen dioxide in the air

Ozone in the air

PM10 particles in the air

PM2.5 particles in the air



Air pollution and visibility

Vehicle emissions and air quality

Wood smoke and air quality

Clean air and future air quality

Your health and the environment: learn and take action

Reviewed 30 March 2022