Sources of Air Pollutants

Anthropogenic Pollutants. These substances come primarily from three sources (1) combustion sources that bum fossil fuel for heating and power, or exhaust emissions from transportation vehicles that use gasoline or diesel fuels (2) industrial processes and (3) mining and drilling. 

Transportation sources, particularly automobiles, are a major source of air pollution and include smoke, lead particles from tetraethyl lead additives, CO, nitrogen oxides, and hydrocarbons. Since the mid-1960s there has been significant progress in reducing exhaust emissions, particularly with the use of low-lead or no-lead gasoline as well as 

Industries may emit various pollutants relating to their manufacturing processes— acids (sulfuric, acetic, nitric, and phosphoric), solvents and resins, gases (chlorine and ammonia), and metals (copper, lead, and zinc). 

Indoor Pollutants. In general, the term indoor air pollution refers to home and nonfactory public buildings such as office buildings and hospitals. Pollution can come from heating and cooking, pesticides, tobacco smoking, radon, gases, and microbes from people and animals. 

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Carbon monoxide was discovered in 1776 by heating a mixture of charcoal and 2inc oxide. It provided a source of heat to industry and homes as a component of town gas and was used as a primary raw material in German synthetic fuel manufacture during World War II its compounds with transition metals have been studied extensively (see Carbonyls). Most recently, carbon monoxide emission from vehicle exhausts has been recognized as a primary source of air pollution (qv). 

Initially, all major sources of air pollution are required to obtain an operating permit. However, any state permitting authority may extend the apphcability of the operating permit to minor sources as... 

Air pollutants may be classified into two broad categories (I) natural and (2) human-made. Natural sources of air pollutants include ... 

The sources of air pollution are nearly as numerous as the grains of sand. In fact, the grains of sand themselves are air pollutants when the wind entrains them and they become airborne. We would class them as a natural air pollutant, which implies that such pollution has always been with us. Natural sources of air pollution are defined as sources not caused by people in their activities. 

Dust storms that entrain large amounts of particulate matter are a common natural source of air pollution in many parts of the world. Even a relatively small dust storm can result in suspended particulate matter read-... 

Even though society has moved toward centralized industries and utilities, we still have many personal sources of air pollution for which we alone can answer—(1) automobiles, (2) home furnaces, (3) home fireplaces and stoves, (4) backyard barbecue grills, and (5) open burning of refuse and leaves. Figure 6-4 illustrates the personal emissions of a typical U.S. family. 

Metallurgical equipment has long been an obvious source of air pollution. The effluents from metallurgical furnaces are submicron-size dusts and fumes and hence are highly visible. The emissions from associated coke ovens are not only visible but odorous as well. 

A mobile source of air pollution can be defined as one capable of moving from one place to another under its own power. According to this definition, an automobile is a mobile source and a portable asphalt batching plant is not. Generally, mobile sources imply transportation, but sources such as construction equipment, gasoUne-powered lawn mowers, and gasoline-powered tools are included in this category. 

In addition to fulfilling the in-house requirements for quality control, state and local air monitoring networks which are collecting data for compliance purposes are required to have an external performance audit on an annual basis. Under this program, an independent organization supplies externally calibrated sources of air pollutant gases to be measured by the instrumentation undergoing audit. An audit report summarizes the performance of the instruments. If necessary, further action must be taken to eliminate any major discrepancies between the internal and external calibration results. 

Control of stationary sources of air pollution requires the application of either the control concepts mentioned in Chapter 28 of the control devices mentioned in Chapter 29. In some cases, more than one system or device must be used to achieve satisfactory control. The three general methods of control are (1) process change to a less polluting process or to a lowered emission from the existing process through modification of the operation,... 

Because mobile sources of air pollution are capable of moving from one local jurisdiction to another, they are usually regulated by the national government. In the United States, state or local agencies can have more restrictive standards, if they choose. Through 1990, only the state of California had established standards more restrictive than the U.S. federal standards, and these only for gasoline-powered automobiles. 

Combustion processes are the most important source of air pollutants. Normal products of complete combustion of fossil fuel, e.g. coal, oil or natural gas, are carbon dioxide, water vapour and nitrogen. However, traces of sulphur and incomplete combustion result in emissions of carbon monoxide, sulphur oxides, oxides of nitrogen, unburned hydrocarbons and particulates. These are primary pollutants . Some may take part in reactions in the atmosphere producing secondary pollutants , e.g. photochemical smogs and acid mists. Escaping gas, or vapour, may... 

Examples of point sources of air pollution, general control methods, and pollution prevention and energy saving practices... 

In addition to chemicals covered under TRI, many other chemicals are released. For example, the EPA Office of Air Quality Planning and Standards has compiled air pollutant emission factors for determining the total air emissions of priority pollutants (e.g., VOCs, SO, NO, CO, particulates, etc.) from many refinery sources. The EPA Office of Aerometric Information Retrieval System (AIRS) contains a wide range of information related to stationary sources of air pollution, including the emissions of a number of air pollutants which may be of concern within a particular industry. With the exception of volatile organic compounds (VOCs), there is little overlap with the TRI chemicals reported above. 

Cumulative Effect the impact on an AQRV resulting from total pollutant loading from all sources including the contributing effects of new and modified sources of air pollution. 

Deals with issues that affect the quality of our air and protection from exposure to harmful radiation. OAR de >el-ops national programs, technical policies, and regulations for controlling air pollution and radiation exposure. Areas of concern to OAR include indoor and outdoor air quality, stationaiy and mobile sources of air pollution, radon, acid rain, stratospheric ozone depletion, radiation protection, and pollution prevention. 

Transportation is a major source of air pollution, particularly in urban environments. The total number of cars, trucks, buses and motorcycles in the world in 1990 was estimated at about 650 million. All these vehicles produce exhaust, and an esti-... 

Unbumt gasoline and cracked hydrocarbons such as ethylene and propylene are also substantial constituents of exhaust. Gasoline contains additives such as benzene, toluene and branched hydrocarbons to achieve the necessary octane numbers. The direct emission of these volatile compounds, e.g. at gas stations, is a significant source of air pollution. Leaded fuels, containing antiknock additions such as tetra-ethyl-lead, have been abandoned because lead poisons both human beings and the three-way exhaust catalyst, especially for the removal of NO by rhodium. 

The sources of air pollution and their control are covered in several books Walk (1997), Heumann (1997), Davies (2000), and Cooper and Ally (2002). 

Table 21.8 is an overview of the major types and sources of air pollutant releases from various pulp and paper processes.12... 

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