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.
Research has shown that ozone mixed with acids can be more harmful than ozone alone.
Scientific studies indicate that the following groups are at particular risk from ozone air pollution. Children at play outdoors . They represent the largest group at high risk from air pollution. In California, there are six million children under the age of fourteen. Ninety percent of them live in areas that fail to meet state and federal air quality standards.