PERSISTENCE PAYS OFF-Complaints about smoke from agricultural burning were at a minimum last year, due in large part to the comprehensive monitoring program.

The area burned totaled 222,000 acres. The basin-wide average haze measurement (COH, or coefficient of haze) during the 70-day season was a relatively low 2.50, compared to 2.97 for 1987. The number of complaints received by local districts and the Air Resources Board also was low: less than 100.

When the season ended, following heavy rains November 21 and 22, total acreage burned was 7,000 more than the previous year (although substantially less than in 1985 and 1986). Largely because of the record-breaking number of stagnant, minimal burn days during October, average daily acreage burned during the season went down somewhat to 3,171 (compared to 3,413 in 1987; 3,727 in 1986; 3,986 in 1985). The number of ready-to-burn acres peaked at 256,000 on November 2, dropping to just below 200,000 at the season's end.

Most smoke complaints were generated on just three days:

• On September 27, a north wind day, three small fires located upwind from Sacramento caused them to be noticed in the downtown area of the city.
• On October 11, more than 9,000 acres were burned when the wind was from the south, but a strong and relatively low inversion layer kept the air trapped in the valley.
• On November 18, another north wind day, damp straw was burned after a light rain and caused additional smoke and fumigation problems.

South winds predominated during the season. Despite the common belief that south winds are good for burning and north winds are bad, the results were mixed. Often good dispersion will occur when dry fields are burned after a storm and north winds gust through the valley. However, burning high moisture fuel will work against good dispersion and create serious air quality problem. Conversely, south wind days tend to be more humid, and burning conditions may be poor if there is a cloud cover and the winds are light.

Other developments:

• For the second year, a computer bulletin board was used to distribute information to participating counties.
• A desktop mapping system was tested with encouraging results.

Meanwhile, new state legislation required all air pollution agencies to meet state air quality standards, which are more stringent than federal standards. Among other things, this means more pressure to control smoke (particulates). The new requirement may impact agricultural burning within the next two years.