It is formed on warm, sunny days when gases or vapors of chemicals called volatile organic compounds mix in the air with nitrogen oxides. Most ozone pollution occurs in late spring, summer and early fall, when the days are longer and there is enough sunlight to heat the chemicals. Most of the air pollutants that form ozone come from many small sources spread over a wide area. Nearly two-thirds of these emissions are from motor vehicles. Vehicle use is growing faster than population in Washington as land use, development, and transportation patterns have fostered continued reliance on cars for basic transportation.
Industry is a smaller contributor to the ozone problem, but is still a significant source.
The commercial, industrial, and residential use of solvents adds to ozone pollution as well. Dry cleaners, gas stations, auto body paint shops, cleaning of mechanical and electronic parts, outdoor burning, and house painting are examples of activities that commonly generate pollutants that form ozone. However, ozone remains a concern due to population growth and increased motor vehicle use. Health effects of ozone Ozone can pose serious health problems. It can irritate and inflame the breathing passages in the lungs, throat, nose, and sinuses.