Sulfur dioxide, nitrogen oxides, volatile organic compounds (VOCs), and particulates are the four major components of air pollution and are the main causes of environmental damage and many diseases, including cancer. The sulfur and nitrogen oxides and particulates are the result of burning petroleum fuels, coal, wood, etc. Printing and coating facilities and foundries, as well as the electronics, petrochemical, metal finishing, and paint industries, produce VOCs, which include solvent thinners, degreasers, cleaners, lubricants, and liquid fuels. They originate from breathing and loading losses from storage tanks, venting of process vessels, and leaks from piping and equipment, wastewater streams, and heat exchange systems. A few common VOCs are methane, ethane, tetrachloroethane, methyl chloride, and various chlorohydrocarbons, perfluorocarbons, styrene, and naphthalenes. The European Community emissions limit is 35 g total organic compounds (TOC) per cubic meter of gasoline loaded (35 g TOC/m ³): the U.S. Environmental Protection Agency emission limit is 10 g TOC/m ³. Particulates from air can be removed using several well established physical methods that use a gravity settler, centrifugal collector, wet spray venturi collector, electrostatic precipitator, and fabric filter.