"Environmental Protection Agency science advisers have recommended the agency strengthen ozone pollution standards in order to protect public health.
Ground-level ozone pollution -- often referred to as smog -- is created by chemical reactions between nitrogen oxide and volatile organic compounds emitted from factories, power plants and vehicles. The EPA's Clean Air Scientific Advisory Committee, in a letter to Administrator Gina McCarthy on Thursday, recommended that the agency toughen its standard by lowering the limit on the amount of ozone pollution to between 60 parts per billion and 70 parts per billion, from the current level of 75 parts per billion.
There is "adequate scientific evidence" to support lowering the limit to a range of 60 to 70 parts per billion, the letter said. But the scientists strongly advised against setting the limit at the higher end of that range, saying that 70 parts per billion "provides little margin of safety for the protection of public health, particularly for sensitive subpopulations." People more sensitive to ozone pollution include those with asthma and other lung conditions, children and the elderly."