SMOKE EMISSIONS FROM PRESCRIBED BURNING OF SOUTHERN CALIFORNIA CHAPARRAL

This report characterizes smoke emissions from small-scale prescribed burns in southern California chaparral. In situ measurements of smoke emissions were made from 12 fires. Three replicate tests were performe d in each of four distinct fuel and fire treatments common to vegetati on management operations: a young and rigorous chamise-dominated stand ; an old and decadent chamise-dominated stand; an old chamise-dominate d stand after crushing; and a stand consisting mainly of old ceanothus . Emission factors for total particulate matter, particulate matter 10 micrograms in size and less, particulate matter 2.5 micrograms in siz e and less, carbon monoxide (CO), carbon dioxide (CO2), methane, and n onmethane hydrocarbons have been developed from the tests. In addition , combustion efficiency and the rates of fuel consumption and heat rel ease were derived from real time measurements of CO, CO2, temperature, and vertical mass flux. The highest combustion efficiencies observed for the flaming phase were from tests at the crushed sites, where most flaming phase emission factors were lower than for the other areas. T hese results suggested positive management implications for crushing. Emission factors from previous tests in untreated (standing) chaparral are combined with the present data, and the average values from the c ombined tests are provided for general use in describing smoke emissio ns from standing chaparral in southern California.