Sulphur dioxide is a sneaky suspect! He is a colourless gas so you can't see him but you can smell him! He smells horrible and he can irritate your eyes and your airway.
The most common natural source of sulphur dioxide is volcanoes and the most common man-made source is the burning of fuels like coal, oil, gas, petrol and diesel.
Sulphur dioxide pollution is much lower than it used to be but it can still cause breathing difficulties, especially for people who have asthma. Often the effects are worse if levels of other pollutants are high too.
Once you've read about all the suspects that cause pollution, take the quiz by clicking below: