They may be produced by combustion or emitted as vapors from fuels, paint, dry cleaners, oil and gas production and refining, or chemical plants. Hydrocarbons can be toxic and play a primary role in the formation of ozone. Ozone Once in the atmosphere, nitrogen oxides and hydrocarbons interact to form ozone-three oxygen atoms linked together instead of the usual two. Since sunlight provides the energy to produce ozone, the amount of ozone in the atmosphere is lower in the early morning and peaks in the late afternoon. In the upper atmosphere a natural ozone layer screens us from harmful ultra-violet radiation, while ozone near the surface of the earth can impair our health.
Humans appear to be among the most sensitive animals to ozone.
Exposure to elevated levels damages our lungs and makes breathing more difficult. It also reduces the ability of the lungs to fight infection and remove inhaled particles. Plants, too, are affected by ozone. Exposure to relatively low concentrations can cause reduced growth and vigor, making them more vulnerable to damage from drought, insects or disease. Carbon Monoxide Carbon monoxide, a single atom of carbon combined with one of oxygen, is highly toxic.