Continue; Major air pollutants
n3. Carbon Monoxide; sources are natural and also from incomplete burning of fossil fuels, mainly auto emissions, it contributes to the global warming and to the formation of ozone at low altitudes
n4. Ozone; Is the primary ingredient of smog, causes eye irritation, nasal congestion, asthma, damage to lung and immune system. (The Ozone layer is ozone at high altitude and protects life by blocking ultraviolet radiation)