As EPA moves to crack down on smog, here’s a closer look at its physical toll

Research on air pollution has been conducted worldwide for decades and is part of the basis for government regulation of air quality. Study after study has found more hospitalizations and higher death rates when certain pollutants are high. In addition to respiratory effects, research has established that air pollution increases the risk of cardiovascular events such as arrhythmia, heart attack and stroke, and the incidence of certain cancers.

Those effects, which can include coughing, a burning sensation in the lungs and shortness of breath, come from inhaling various particles from smoke and exhaust that make lung tissues swell and airway passages narrow. Brisk exercise exacerbates the effects (when and how severe those are vary from person to person). Because muscles need more oxygen to work, breathing rates increase by about seven times.... As a result, the lungs take in and expel double to triple the normal amount of air -- dramatically increasing their exposure to pollutants.’ This is especially problematic for people with coronary artery disease.

Everyone is familiar with the gray-brown haze that often blankets Los Angeles, and the fact that the city consistently ranks as one of the most polluted in America. But what many may forget is that the dismal reports of L.A.’s air pollution only capture the average amounts of toxins in the air, and that some places within the urban sprawl are far dirtier than others. Official numbers do not take into account the fact that pollutants are at much higher levels within a few hundred feet of the freeways that crisscross the city -- and for the adults and kids who live, work or go to school there, the effects add up.