May marks more than the beginning of long-awaited warm spring weather; it’s also the beginning of ozone season, according to the U.S. Environmental Protection Agency. ABOVE: The Most Polluted Cities in America Ozone season is the time when warm, sunny weather helps form smog from power plant emissions, cars and trucks, factories and even some consumer products, like hair spray, spray paint and insecticide, damaging both population health and the environment. Increased ozone levels can cause coughing, wheezing, chest pain,...