In this report we have attempted to develop an interpretation of the likely effects of near ambient concentrations of NO2. It is our assessment of the risk due to exposure. We have placed considerable emphasis on analysis of a range of effects and on inclusion of persons who are likely to be most sensitive. Far preferable for standard-setting activities would be an accurate description of both the short- and long-term effects of various exposures to NO2. Thus, the standard-setting acitivity is left with major uncertainties of biologic effect. Given such an assessment, with all its uncertainties, the new view is that it is now up to the standard-setting activity to decide what degree of risk society will accept. The older view was that the biologic uncertainties, together with monitoring uncertainties and allowance for poorly known enhancing or aggravating factors, such as other pollutants, go into a safety factor. For example, the World Health Organization recommended that a safety factor of 3 to 5 be applied to the short-term effects NO2 concentration of 0.5 ppm (940 μg per m3) to get a range or standard of 190 to 320 μg per m3 not to be exceeded more than once per month. See also Morrow's classic approach to a long-term standard. Such a classic procedure is unsophisticated, but despite the wide range of data and availability of modern probabilistic techniques of estimation, we are still left with a difficult job to do convincingly better.
|Original language||English (US)|
|Number of pages||12|
|Journal||American Review of Respiratory Disease|
|State||Published - 1979|
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine