Cholesterol is a component of cell membranes and is an example of which type of lipid?.

Poisonous gases, Particulate matter,Vehicle Exhaust Pollution, burning of fossil fuels  etc are the biggest source of air pollution.

Explanation: Presence of harmful substances in the air is known as Air pollution. Above sources make the air polluted and are the biggest sources  of Air pollution.

Nitrogen dioxide, Carbon monoxide , sulfer dioxide , are the main sources of air pollution. Particulate matter is the mixture of smoke, dirt, dust and other tiny particles which can not be seen by nacked  eyes inhance air pollution. Discharge from vehicles, burning of fossil fules are also inhance air pollution.