Agricultural Burning
Program-90
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The fall agricultural burning season got under way
on September 15 and ran for 77 days through November 30. Nearly 165,000
acres were burned, an increase of 35,000 acres over last year.
Although air quality remained good, the number of complaints to the state
Air Resources Board was higher than any year since the program began in
1981. Strong atmospheric inversions in the fall of 1990 combined with
burning on high north wind days may have been a factor. Higher coefficient
of haze (COH) readings in the month of November occurred between
6 p.m. and midnight, a time when emissions from fireplaces and wood stoves
significantly affect those values.
The limited air circulation associated with the persistent inversions also
reduced burning. There were 13 no-burn days during the fall burning period
because of new, more stringent criteria. "Even
with far superior meteorological conditions in 1980, the average
basinwide COH was much worse than it is today."
Last year the program began monitoring daily burning by management zone and
crop type. This facilitated additional computerized analysis of burning
patterns. Refinements in the analysis of monitoring data has enabled program
personnel to "see a better picture" of air pollution in the Sacramento
Valley. The analysis suggests little or no correlation between agricultural
burning and pollution monitoring data gathered from locations throughout the
Sacramento Valley.
Is the program working? The table included in this section of the report
compares data from the first 10 years, along with the old program in effect
in 1980. The old program was based on the burn/no-burn criteria that forced
more burning into fewer days and concentrated burning in sub-areas of the
Valley. What it shows is that even with far superior meteorological
conditions in 1980, the average basinwide COH was much worse than it is
today and a continuing trend of improving air quality.
The program's success can be attributed to several elements: variable
acreage allocations valleywide distribution of burning; shortened burn
hours; availability of current air quality, meteorological and burn data;
use of computers to store, transmit and analyze data; and flexible program
policies and procedures.
Although the agricultural burning program continues to protect and improve
Sacramento Valley air quality, making decisions under changing weather and
air quality conditions is a difficult task. The following recommendations
have been made to improve the program:
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