In our county, ozone and particulate matter pose the greatest health threat. In the upper atmosphere, ozone occurs naturally and protects us from the sun s ultraviolet radiation. At ground level, ozone results from pollution and can harm our health. Ground-level ozone is the primary ingredient of smog in our cities. Sources for these pollutants include motor vehicles, power plants, factories, chemical solvents, combustion products from various fuels, and consumer products.
Ozone can cause numerous health effects.
Ozone exposure can also reduce resistance to infections. Research has shown that immune system cells move into the lungs after acute exposure to ozone, producing a nine-fold increase in disease fighting cells. In addition, short-term ozone exposure has also been shown to decrease resistance to bacterial pneumonia in animal studies. In Southern California, the effects of ozone can be complicated by the presence of other pollutants, such as nitric acid, particulate matter and nitrogen dioxide. In coastal areas, it is common for the population to be exposed to acidic fog in the morning, followed by exposure to high concentrations of ozone during sunny afternoons.