Why does it matter?
Clean air is a requirement for a healthy life for us and all plants and animals on the planet. When we breathe in the pollutants over a long time period, they can lead to a number of health conditions associated with the lungs and heart.
The effects are seen more in children, as their bodies are still developing and growing and because they are generally shorter in height, they are closer to the source of pollutants from vehicles.
High levels of pollutants landing on the earth can change soil nutrient levels, make lakes and stream more acidic, damage crops and cause acid rain.