Levels of ground-level ozone -- a major component of smog -- are expected to exceed safe levels later today, as pollution bakes in the hot summer air. Meanwhile, the heat itself continues to cause health problems.
Heat is the number one weather-related killer, at least among weather events that aren't emergencies, like hurricanes, according to the National Oceanographic and Atmospheric Administration. Heat also contributes to air pollution, which also leads to premature death, according to research, but which has a more insidious effect that is only seen over a long time scale.
This map shows a forecast for levels of ozone at 7 p.m. tonight, after hourly ozone measurements are averaged for 8 hours. Because ozone causes damage over time, government regulators measure ozone pollution levels as an average over time. Areas in yellow and red exceed the Environmental Protection Agency's proposed limits on ground-level ozone.
Those limits are set to protect vulnerable populations, such as the very young or old, those with existing heart and lung diseases, and those who work or exercise outdoors. NOAA Ozone forms when emissions of volatile organic compounds and nitrogen oxides from tailpipes and smokestacks mingle in heat and sunlight.
The result is ozone -- a key part of the upper atmosphere, but a damaging addition to the lower atmosphere. The gas can damage lungs, scarring tissue, triggering asthma attacks and other lung diseases, and contributing to heart disease.
Enter your city or zip code to get your local temperature and air quality and find local green food and recycling resources near you.