Agricultural Burning



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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:

  • Increase fines and establish a minimum fine for burning violations. Reaffirm the policy that all interested parties be cited if no single violator can be faulted.
  • Improve burning policies and procedures (e.g. stagger burning times) to deter concentrated burning in any one area during any particular time of the day.
  • Increase aerial surveillance to ensure enforcement of program procedures, facilitate analysis of program change, and improve valleywide coordination.
  • Request the state Air Resources Board to increase frequency of COH samples from current two hour intervals.
  • Install new air monitoring devices at the Marysville airport to analyze complaints of smoke in the vicinity.
  • Formalize the update procedures with the ARB to provide more consistent and efficient acreage allocations on good burn days.
  • Refine communication with growers so that burning logistics can be improved.
  • Require all burn allocations to be handled through local Air Pollution Control Districts.

Annual Comparison

Year Ave
# days
# days
1980 4.50 128/NA* 0.35 7.00 7.20 17 2 220,000
1981 3.40 24/NA 4.36 7.09 6.02 45 11 167,000
1982 2.74 32/NA 3.34 6.48 5.82 46 8 239,000
1983 3.25 35/35 2.03 5.85 6.30 45 6 213,000
1984 1.99 57/121 3.49 3.30 6.90 43 14 230,000
1985 2.77 51/102 1.91 9.10 6.60 69 11 275,000
1986 2.52 59/114 0.88 8.40 6.70 77 14 287,000
1987 2.97 13/37 2.09 12.70 5.00 63 15 215,000
1988 2.50 11/79 1.00 11.40 6.00 70 13 222,000
1989 2.53 4/10 5.85 11.10 6.00 74 14 130,000
1990 2.04 148/87 0.53 11.00 6.00 64 8 165,000
*NA =  not available

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