Polluted air is bad for our health because it causes respiratory diseases (e.g. chronic bronchitis, asthma) and other severe conditions (e.g. difficulties when breathing, cardiac problems, heart attacks).

When the air is polluted, animals’ behaviour can also change. For example, birds sing less, bees abandon their hives, migration patterns change, and animals are less likely to procreate.

The environment is damaged also. Air pollutants can increase the acidity of land and water (acidification), cause an overload of nutrients in water leading to algal blooms and reduce vegetation growth. Air pollution can also change the colours and clarity of landscapes.

It is important to distinguish air pollutants that are toxic for human health from greenhouse gases, which trap heat from the sun and increase the planet’s temperature, leading to global warming.