A few common air pollutants are found all over the United States. These pollutants can injure health, harm the environment and cause property damage. Although EPA has been regulating criteria air pollutants since the 1970 CAA was passed, many urban areas are classified as non attainment for at least one criteria air pollutant. It has been estimated that about 90 million Americans live in non attainment areas. Southeastern Wisconsin is a non attainment area for Ozone.
Cars are an important source of VOCs.
Carbon-containing chemicals are called organic. Volatile chemicals escape into the air easily. Many VOCs, such as the chemicals listed in the table, are also hazardous air pollutants, which can cause very serious illnesses. EPA does not list VOCs as criteria air pollutants, but they are included in this list of pollutants because efforts to control smog target VOCs for reduction. Cars are an important source of NO2.