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Ozone Alert Values

Ground level air quality alerts
Too much ozone at ground level can make your eyes smart, can reduce your lung capacity and, in extreme cases, can make it hard to breathe. Too much ozone at ground level can make even a very fit person, an athlete-in-training, pretty sick.

Local broadcast and newspaper air quality alerts generally correspond to federal ozone standards:

Ozone Index ValuePrecaution
0-50 (good-GREEN)Best for outdoor activity.
50-100 (moderate-YELLOW)Unusually sensitive people should consider limiting prolonged outdoor exertion.
101-150 (unhealthy-ORANGE)Active children and adults, and people with respiratory disease such as asthma, should limit prolonged outdoor exertion.
151-200 (unhealthy-RED)Exercise early/late; indoors when possible. Everyone, especially children, should avoid (if sensitive) or limit prolonged outdoor exertion.
Above 200 (very unhealthy-PURPLE)Active children and adults, and people with respiratory disease such as asthma should avoid all outdoor exertion. Everyone else should limit outdoor exertion.
Note: When ozone begins to rise, fires, outdoor grilling and individual auto use should be restricted.
Ultraviolet (UV) Alerts
To help avoid painful sunburn and blisters and such long-term problems as skin cancer and sight-dulling cataracts, many weather reports now include information on the UV Index.
Using two National Oceanic and Atmospheric Administration-operated satellites, the National Weather Service and the Environmental Protection Agency forecast the UV risk (or Index Value) based in part on the wavelengths of the UV radiation (some being more harmful than others) and on whether clear skies or cloudy are expected. They then suggest preventive actions:
UV Index ValuePrecaution
0-2 (minimal)Wear hat or cap.
3-4 (low)Hat and sunscreen of SPF 15 or more.
5-6 (moderate)Hat, sunscreen of 15+, stay in shady areas.
7-9 (high)As above, plus stay indoors 10 a.m. to 4 p.m.
To reduce the risk of cataracts and other eye damage, sunglasses are advised for UV values of 5 (moderate) or higher. Good sunglasses are also advised at the beach, on the water, or on snow, at all times, even when the index is minimal.
Additional Resources - Provides users with a real-time ozone map of the city of Houston. - A Houston non-profit organization dedicated to influencing public policy on air quality and environmental health issues. - An environmental advocacy organization that conducts environmental research and promotes environmental solutions.