Noncriteria Pollutants and Air Quality Standards

A number of pollutants have documented effects on people, plants, or materials at concentrations, or approaching those, found in polluted air (e.g., see Bascom et al., 1996a,b). In the United States, seven of them are known as criteria, pollutants and national ambient air 

NAAQS and the recommended values or limits set by some other countries and the World Health Organization are given in Tables 2.6 and 2.7. (Note that the data in Table 2.7 were compiled in the early 1990s and there may therefore be some changes since then.) Ambient air quality standards have two 

TABLE 2.7 Some Ambient Air Quality Standards (in ppm) for Some Gases  

The United States sets two types of NAAQS, primary and secondary. They are based on information contained in air quality criteria documents that contain a wealth of information on all aspects of the criteria pollutants, as do the documents by the World Health Organization. These should be consulted for detailed information and references regarding pollutant sources, ambient levels, chemical transformations, effects, and so on. 

Note that the definition of a U.S. primary ambient air quality standard is one designed to protect the 

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