Particulate matter, fine, from power plants

Electrostatic precipitators that are suitable for removal of fine particulate matter, such as fly ash, from power plant flue gases operate on the principle of charging the particles with ions followed by collection of the ionized particles on a surface from which they are subsequently removed. Fabric filtration, which is used for removal of extremely fine particulate matter, is accomplished in a bag-house in which are hung a number of filter bags through which the gas stream flows. 

Particulate matter is found near roads and some industries, in smoke and haze it can be directly emitted from sources such as forest fires, and it can be formed when gases emitted from power plants and automobiles react in the air. The NAAQSs for particulate matter, revised in 2006, are set at 150 xg/m as the 24-h average for coarse particulates (2.5- to 10-pm diameter) and are set at 35 pg/m as the 24-h average for fine particulates (. 5-pm diameter) [12], Particle pollution is controlled by reducing directly emitted particles and by reducing emissions of pollutants that are gases when emitted, but form particles in the atmosphere. In the United States in 2006, the average concentration of fine particulates amounted to about 13 xg/m [13]. 

A more effective approach to clean air policy, and one example of a sensible program being implemented by the federal government, is the Clean Air Interstate Rule or CAIR, intended to reduce emissions of particulate matter and NO in the eastern United States. EPA finalized the CAIR rules on March 10, 2005 in response to a finding of non-attainment of National Ambient Air Quality Standards (NAAQS) for fine particulate matter and ozone formation. CAIR requires reductions in SOj and NOj emissions from coal-fired power plants the emissions limits spelled out in the CAIR plan affect electric utilities in 28 eastern states and the District of Columbia. Emissions reductions are to be achieved through a market-based cap-and-trade system similar to other air pollution programs EPA has put into practice over the last few decades. 

Particulate matter (PM) is found in flue gas from PC power plant and in raw syn gas from coal gasification. PM causes air pollution, and it is regulated by the U.S. EPA. PM2 5 is a fine particle standard (<2.5 pm particles) with the 24 h emissions regulated at 35 pg/m PMjq is a coarse particle standard (<10 pm particles) with the 24 h emissions regulated at 150 pg/m [62]. 

---