Respirable suspended particulates
WHO guidelines 50 μg/m3
24-hour avg
Tiny pieces of matter so small they can penetrate deep into the lungs, and cause respiratory illnesses and cancer.Fine suspended particulates
WHO guidelines 25 μg/m3
24-hour avg
Tiny pieces of matter so small they can infiltrate the bloodstream, causing cancer and other life-threatening illnesses.Nitrogen dioxide
WHO guidelines 200 μg/m3
1-hour avg
Can cause inflammation of airways and can combine with other pollutants to create ozone, a component of smog.Ozone
WHO guidelines 100 μg/m3
8-hour avg
Can trigger chest pain, irritation and inflammation of airways. Ozone can also worsen ailments related to breathing, like emphysema.Sulphur dioxide
WHO guidelines 500 μg/m3
24-hour avg
Sulphur dioxide can cause respiratory illnesses, and aggravates existing health problems like asthma. Additionally, it is a component of acid rain.Carbon monoxide
A colourless, odourless, poisonous gas that is a component of vehicle exhaust.