Ozone (O3) is a colorless gas naturally located high in the atmosphere, which helps shield the earth from the sun’s damaging ultraviolet rays. However, when ozone exists at ground level it can be harmful to our health. Ground-level ozone is created when volatile organic compounds (VOC) and nitrous oxides react in the presence of sunlight. This type of ozone has been shown to be the cause of numerous adverse health effects, contributing to diseases of the respiratory system and increasing the risk of heart disease.
Pollution from our modern industrial world is the greatest contributor to ozone formation. The exhaust from motor vehicles contributes approximately 70% of the nitrous oxide pollution and 50% of the VOCs in the atmosphere that react to create ozone. Industrial agriculture and its abundant use of petrochemicals for fertilizers, pesticides and machinery is also a major contributor to nitrous oxide pollution. The application of chemical fertilizers alone accounts for 68% of total U.S. nitrous oxide emissions, according to the Environmental Protection Agency (EPA). Other sources include aircraft, oil refineries, paints, solvents and garden equipment.
The most common adverse health effect of ground-level ozone is its contribution to asthma and other lung diseases. Those with asthma suffer more frequent and severe attacks when ozone levels rise. Symptoms often worsen in those suffering from chronic bronchitis or emphysema, and even those with healthy lungs can find themselves contracting respiratory infections more often when ozone levels are high.
Studies have shown that ozone also contributes to an increased risk of death from heart disease and stroke. A 2007 study in the British Medical Journal reported that researchers found that of 100 million people who took part in the National Mortality and Air Pollution Study (NMMAPS) between 1987 and 2000, which studied the connection between health and air pollution, the higher the ozone, the higher the rate of deaths from heart disease and stroke. As the summer temperatures rise, so does ozone’s health danger. Deaths from heart disease and stroke on a day where temperatures rose considerably during the day were 1% higher at the lowest ozone level and 8% higher when ozone was at its highest.
Most summertime weather reports will include the projected ozone level for the day, so if you are among those groups sensitive to ozone, such as children, the elderly and those with asthma or other lung diseases, keep the following suggestions in mind:
- Ozone level 0-50: Good health impact. You can perform activities as usual.
- Ozone level 51-100: Moderate health impact. Can be unhealthy for those unusually sensitive to ozone, who should limit prolonged outdoor activities.
- Ozone level 101-150: Unhealthy for sensitive people. Limit prolonged outdoor activities.
- Ozone level 151-200: Unhealthy. Sensitive groups should avoid prolonged outdoor activities, and everyone else should keep prolonged activity limited.
- Ozone level 201-300: Very unhealthy. Sensitive groups should avoid all outdoor activity, and everyone else should keep any outdoor activity limited.
Some governments are attempting to solve the ozone problem by encouraging the development of alternative fuels and implementing increased fuel efficiency standards. You can do your part by using your vehicle less often, buying fuel-efficient products and products such as paints and solvents that are more environmentally friendly and do not contain VOCs.