Between May and September, emissions called volatile organic compounds (VOCs) and nitrogen oxides (NOx) released from internal combustion engines chemically react in sunlight on hot, windless days and form ground-level ozone, a major component of smog. When weather conditions project the possibility of high ground-level ozone, the Oklahoma Department of Environmental Quality declares an Ozone Alert Day.
Ozone Alert Days mean air pollution is expected to reach unhealthy ranges. Ozone exposure is a health risk to the entire population but particularly sensitive are children, the elderly, anyone with respiratory or cardiovascular illnesses and anyone who experiences prolonged exposure.
Ozone Alert Days serve to notify the public that they should make voluntary changes to reduce their contribution to dangerous ground-level ozone.
President John F. Kennedy