Sulfur dioxide primary pollutant

Primary pollutants are emitted directly from the sources and remain unchanged once they enter the environment. Examples include particulate matter and inorganic gases, such as sulfur dioxide. Secondary pollutants, for example sulfurous acid, are formed in the atmosphere by chemical reactions involving primary pollutants and gases normally present in the air. 

Emissions to the atmosphere from ammonia plants include sulfur dioxide (SOj), nitrogen oxides (NOJ, carbon monoxide (CO), carbon dioxide (COj), hydrogen sulfide (HjS), volatile organic compounds (VOCs), particulate matter, methane, hydrogen cyanide, and ammonia. The two primary sources of pollutants, with typical reported values, in kilograms per ton (kg/t) for the important pollutants, are as follows ... 

The Clean Air Act recognizes a number of so-called primary air pollutants, and the EPA has established standards for these substances. Ozone, nitrogen oxides, and sulfur dioxide are among these (the others are carbon monoxide and lead, discussed below, and total suspended particulates ). The EPA s standard for ozone is 0.08 parts of the gas per million parts of air (0.08 ppm), averaged over eight hours. Standards also exist for the oxides of sulfur and nitrogen. These are designed to prevent chronic respiratory toxicity of any kind. 

The advantage of this technique is the rapidity of monitoring for many compounds simultaneously, including some of the liquid and solid inorganic materials—such as sulfuric acid, ammonium sulfate, and ammonium nitrate—that may be the final products of the primary pollutants nitric oxide and sulfur dioxide. Also, monitoring the many par-... 

Chemicals can be labeled as either a primary air pollutant or secondary air pollutant. Primary air pollutants are those such as carbon monoxide and sulfur dioxide that enter the atmosphere directly as a result of human or natural events. Carbon monoxide s primary source in the atmosphere is the incomplete combustion of gasoline. Hundreds of different chemicals are present in gasoline. The combustion of octane, C Hj, can be used to represent the general reaction of hydrocarbons in an automobile engine to produce energy ... 

The primary cause of acid rain is industrial and automotive pollution. Each year in industrialized countries, large power plants and smelters that burn sulfur-containing fossil fuels pour millions of tons of sulfur dioxide (S02) gas into the atmosphere, where some is oxidized by air to produce sulfur trioxide (S03). Sulfur oxides then dis-l solve in rain to form dilute sulfurous acid and sulfuric acid ... 

Power plants and refineries are the primary fixed sources of pollutant emissions in most urban areas. However, other industrial sources, distributed throughout the area, also emit substantial amounts of contaminants. Also during the winter months effluents from home heating can add significantly to the pollutant load in the atmosphere. Sulfur dioxide and particulates are emitted from nearly all fixed sources although many of the particulate emissions are controlled by the use of abatement devices and sulfur dioxide by the use of low sulfur fuels. Also, power plants emit large amounts of nitrogen oxides, and refineries, hydrocarbons. 

A few years ago the World Health Organization came to much less uncertainty when stating the toxicity of the most important air pollutants in more general terms and proposing the corresponding noxious concentrations and subsequent air quality standards (WHO, 1972). The way followed in this case has been much less mathematic and more length,y but the consensus arrived at by various sets of experts on SO2 effects can be considered unanimous, even if did not consider in detail sulfate deposition and sulfate aerosol secondary toxicity generated by the primary pollutant sulfur dioxide. 

This model has been exercised on a variety of AQCR s for which an accurate emission inventory, meteorological data base, and measured ground level pollutant concentrations are available. The results discussed in this paper represent analyses of the New York, Philadelphia, Niagara Frontier, St. Louis, and Milwaukee AQCRs 13, 14). These AQCRs represent a reasonable cross-section of the eastern urban AQCRs where the primary sulfur dioxide ambient air quality problem exists. The results of these analyses indicate that the level of control required by emission source to achieve ambient air quality standards can be forecast with greatly increased assurance. The following conclusions from this exercise should be considered in the near-term achievement of ambient air quality standards. 

The State implementation programs for sulfur dioxide and other pollutants were submitted after January 1972 for EPA approval or rejection by May 1972. Each program plan was to achieve primary and secondary standards. 

Reductions in ambient concentrations of some but certainly not all air pollutants have taken place over the past decade. In the United States, the US Environmental Protection Agency (EPA) is the primary agency responsible for promulgating and regulating air pollution standards. National ambient air quality standards (NAAQS) have been established for six classes of outdoor pollutants lead, carbon monoxide, ozone, nitrogen dioxide, sulfur dioxide, and particulate matter. These standards (Table 1) are periodically reviewed and updated based on currently available data regarding adverse health effects. Bases on new evidence, the standards for ozone and... 

Sulfur dioxide (SO2) is a colorless and nonflammable gas with a pungent odor. It is used commercially to preserve fruits and vegetables and as a disinfectant in food production. It is also used in bleaching straw and textiles. Liquid SO2 can be produced by pressurizing the gaseous form and then used as a solvent. Sulfur dioxide is also a primary component of air pollution. 

---