What is ozone and why is it a problem?
Ozone gas can be found in both the upper and lower atmospheres. The ozone layer in the upper atmosphere exists naturally and is essential to life because it filters harmful ultraviolet radiation from the sun, reducing the amount reaching the earth’s surface. High concentrations of ozone near ground level, however, can be harmful to people, animals, crops, and other materials. Ground level ozone is the main ingredient in urban and regional smog. It is created when air pollutants from a variety of sources react in sunlight. The main ozone-causing pollutants are volatile organic compounds (VOCs) and nitrogen oxides (NOx). Because heat and sunlight are also important factors in ground-level ozone formation, ozone pollution is primarily a concern from April through October. Motor vehicles account for about 30-40% of the ozone-causing pollutants in the Baltimore and Washington areas, but other sources include lawnmowers, boats, many household products, power plants, and industrial facilities
