How is smog formed?
Smog is made up, in large part, of ozone gas. It’s formed in the lower atmosphere just above the Earth’s surface when energy from the sun reacts with industrial pollutants and motor vehicle exhaust particles in the air. The pollutants and the exhaust contain two key components to the development of smog: • Nitrogen oxides These are produced when fossil fuels like gasoline, natural gas, heating oil and coal are burned. These gases are also produced naturally in the soil and in forest fires and volcanoes. • Volatile organic compounds (VOC) These are compounds containing carbon and, in most cases, hydrogen. However, most of these compounds also contain oxygen, nitrogen, chlorine, sulphur or phosphorous. The major artificial source of VOC emissions is motor vehicles, but the evaporation of gasoline, oil-based paints, nail polish remover, barbecue starter, surface coatings, inks and hydrocarbons from the petrochemical industry is also a significant source. Both nitrogen oxides and volatile
