Biomass burning as a source of formaldehyde, acetaldehyde, methanol, acetone, acetonitrile, and hydrogen cyanide

Using a novel experimental technique, based on proton transfer reaction mas s spectrometry, from measurements of emissions from laboratory scale biomas s burning experiments, we have estimated the source strengths of several po tential HOx producing gases: formaldehyde, acetaldehyde, methanol and aceto ne. The derived global average emissions are 5-13; 3.8-10; 1.5-4; 2.3-6.1 T g y(-1), respectively. The resulting global average HOx production from pho tochemical decay of these gases is 3 x 10(9) molecules cm(-2) s(-1). Althou gh relatively small in a global context, these emissions are significant fo r the photochemistry in fresh fire plumes. From our measurements are also e stimated global source strengths from biomass burning for CH3CN and HCN of 0.4-1.0; 0.2-0.6 Tg y(-1), respectively. The biomass burning emissions of C H3CN may well dominate the global source of this compound, which thus might well be a unique tracer for biomass burning. Some discrepancies between ex perimental studies must, however, be resolved.