Air Pollution and Illness
Almost 5 million people die each year because of air pollution. In fact, polluted air causes more deaths than traffic accidents. Air pollution harms the respiratory and circulatory systems. Both outdoor and indoor air can be polluted.
Outdoor Air Pollution
The Air Quality Index (AQI) is an assessment of the pollutants in the outdoor air based on their human health effects. The health risks associated with different values of AQI are shown in Figure 1.8. When AQI is high, you should limit the time you spend outdoors. Avoiding exposure to air pollution can help limit its impact on your health.
People with certain health problems, including asthma, are very sensitive to the effects of air pollution. They need to be especially careful to avoid it.
AQI generally refers to the levels of ground-level ozone and particulates. Ozone is a gas that forms close to the ground when air pollutants are heated by sunlight. It is one of the main components of smog. Smog also contains particulates. Particulates are tiny particles of solids or liquids suspended in the air. They are produced mainly by the burning of fossil fuels. The particles settle in airways and the lungs, where they cause damage.
Air quality is especially important for sensitive people. They include people with asthma, other respiratory illnesses, and cardiovascular diseases.
Smog clouds the city of Los Angeles, California. Visible air pollution in the form of smog is a sign that the air is unhealthy.
Indoor Air Pollution
Indoor air may be even more polluted than outdoor air. It may contain harmful substances such as mold, bacteria, and radon. It may also contain carbon monoxide. Carbon monoxide is a gas produced by furnaces and other devices that burn fuel. If it is inhaled, it replaces oxygen in the blood and quickly leads to death. Carbon monoxide is colorless and odorless, but it can be detected with a carbon monoxide detector like the one.