That unusual and horrific combination of man- made pollution and weather ushered in a new era of understanding regarding the health impacts of air pollution, and awakened a new awareness of the impact of human activity on our quality of life. Obviously, we have made tremendous progress since that terrible incident. Since 1990, EPA has also put in place rules that will prevent 1.5 million tons of toxics from being released into our air. The work of the states, local governments, federal government and the various industries have brought about these dramatic improvements, and all Americans are better off because of it. The role of weather and other natural factors in air pollution remains a fact of life.
Weather can exacerbate air pollution problems.
The tragedy in Donora involved an unusual meteorological episode, but what made it deadly was the human-caused pollution in the air. Our knowledge about these kinds of interactions has evolved over the years, and so have our policies and standards. The history of how states and EPA have worked together to develop programs to address ground-level ozone is an excellent example of how EPA's approaches factor in unusual climatic episodes in developing plans to reduce emissions. Ozone is unhealthy to breathe, even at low levels. It affects a variety of individuals, including healthy children and adults who are active outdoors during the summer.