Particle emissions and the production of ozone and nitrogen oxides from the burning of forest slash

• Published in: Atmospheric environment 1981, Vol.15 (1), p.73-82
• Main Authors: Stith, Jeffrey L, Radke, Lawrence F, Hobbs, Peter V
• Format: Article
• Language: English
• Subjects: air pollution
• ISSN: 0004-6981; 1352-2310
• DOI: 10.1016/0004-6981(81)90127-X

Airborne measurements in the plumes from three prescribed burns of conifer slash showed the number concentration-size spectra to be bimodal with peaks at ~0.1 and ~0.5 μm. The mass distribution was sharply peaked at ~0.3 μm where over 80% of the mass of the particles in the plume resided. Most of the particles in the plumes were of primary rather than secondary origin. The burns emitted particulate mass into the atmosphere at rates of 0.1–15 kg s −1 during the active burning phase. The average density of the particles ranged from 0.75 to 1.34 g cm −3. Estimates of particle emission factors for the burns ranged from 0.2 to 2%, higher values being associated with higher fuel consumption rates. The burns were prolific sources of cloud condensation nuclei (CCN), producing ~10 10−10 11 CCN per gram of wood consumed. The CCN resulted in anomalously high concentrations of water droplets < 10 μm diameter in the cumulus clouds produced by the burns. Ozone concentrations near the tops of the plumes reached values as high as 44 ppb above ambient values, the higher values generally being associated with high u.v. intensities. Peak concentrations of NO 2 and NO in the plumes were ~60 ppb; the ratio of NO x NO ranged from 1 to 3. SO 2 was not found in the plumes.