The impact of an 8-hour ozone air quality standard on VOC and NO{sub x} controls in Southern California
- Ford Motor Co., Dearborn, MI (United States)
The National Ambient Air Quality Standard for ozone is presently being revised by the U.S. Environmental Protection Agency. It appears likely that the revised standard will be for the daily-maximum 8-hour ozone concentration. The form and the level of the standard, which directly determine the stringency of the standard, are still being developed. To study the impact of an 8-hour based standard on VOC and NO{sub x} controls in Southern California, we established a matrix of control scenarios for the August 26-28, 1987 episode observed during the Southern California Air Quality Study, using more realistic input information and the Urban Airshed Model with improved transport and chemistry algorithms. The matrix is based on uniform anthropogenic emission controls. The 8-hour peak positions tend to be significantly displaced from the 1-hour peak positions while the mid-times of occurrence of the 8-hour and 1-hour peaks are comparable. There are no major changes in the emission control requirements for a reduction of peak ozone from the episode level to 120 ppb in the 1-hour case and to 90 ppb in the 8-hour case. Reduction in afternoon episodic ambient temperatures by 5 percent shifts the peak ozone levels downward by some 20 ppb but there is little impact on emission control requirements. Parameters used in observation-based models such as O{sub 3}/NO{sub y} are not sufficiently sensitive to separate the VOC-control region from the NO{sub x}-control region for both 1-hour and 8-hour concentrations.
- OSTI ID:
- 466100
- Report Number(s):
- CONF-9606185--
- Country of Publication:
- United States
- Language:
- English
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