EFFECTS ON VISIBILITY AND MATERIALS

TABLE 2.9 Some Noncriteria Pollutants and Typical Concentration Ranges Observed from Remote Areas to Severe Air Pollution Episodes in Urban Areas 

Ozone Formaldehyde Nitric PAN Formic Total associated 

FIGURE 2.22 Maximum concentrations of some trace pollutants and the percentage of the peak ozone they form when summed. Also shown is the California Air Quality Standard for O, and the various alert levels (from Tuazon et at., 1981). 

Scattering of light by gaseous air pollutants is negligible compared to the Rayleigh scattering by 02 and N2 because of the very low concentrations of pollutants compared to those of the major components of air. 

Elemental carbon is believed to be the major significant light-absorbing species in particles. In remote regions, absorption may only account for 5-10% of the total extinction, whereas in urban areas, its contribution is greater, up to 50%. 

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