TY - JOUR
T1 - Isocyanic acid in the atmosphere and its possible link to smoke-related health effects
AU - Roberts, James M.
AU - Veres, Patrick R.
AU - Cochran, Anthony K.
AU - Warneke, Carsten
AU - Burling, Ian R.
AU - Yokelson, Robert J.
AU - Lerner, Brian
AU - Gilman, Jessica B.
AU - Kuster, William C.
AU - Fall, Ray
AU - De Gouw, Joost
PY - 2011/5/31
Y1 - 2011/5/31
N2 - We measured isocyanic acid (HNCO) in laboratory biomass fires at levels up to 600 parts per billion by volume (ppbv), demonstrating that it has a significant source from pyrolysis/combustion of biomass. We also measured HNCO at mixing ratios up to 200 pptv (parts-per-trillion by volume) in ambient air in urban Los Angeles, CA, and in Boulder, CO, during the recent 2010 Fourmile Canyon fire. Further, our measurements of aqueous solubility show that HNCO is highly soluble, as it dissociates at physiological pH. Exposure levels >1 ppbv provide a direct source of isocyanic acid and cyanate ion (NCO-) to humans at levels that have recognized health effects: atherosclerosis, cataracts, and rheumatoid arthritis, through the mechanism of protein carbamylation. In addition to the wildland fire and urban sources, we observed HNCO in tobacco smoke, HNCO has been reported from the low-temperature combustion of coal, and as a by-product of urea-selective catalytic reduction (SCR) systems that are being phased-in to control on-road diesel NOx emissions in the United States and the European Union. Given the current levels of exposure in populations that burn biomass or use tobacco, the expected growth in biomass burning emissions with warmer, drier regional climates, and planned increase in diesel SCR controls, it is imperative that we understand the extent and effects of this HNCO exposure.
AB - We measured isocyanic acid (HNCO) in laboratory biomass fires at levels up to 600 parts per billion by volume (ppbv), demonstrating that it has a significant source from pyrolysis/combustion of biomass. We also measured HNCO at mixing ratios up to 200 pptv (parts-per-trillion by volume) in ambient air in urban Los Angeles, CA, and in Boulder, CO, during the recent 2010 Fourmile Canyon fire. Further, our measurements of aqueous solubility show that HNCO is highly soluble, as it dissociates at physiological pH. Exposure levels >1 ppbv provide a direct source of isocyanic acid and cyanate ion (NCO-) to humans at levels that have recognized health effects: atherosclerosis, cataracts, and rheumatoid arthritis, through the mechanism of protein carbamylation. In addition to the wildland fire and urban sources, we observed HNCO in tobacco smoke, HNCO has been reported from the low-temperature combustion of coal, and as a by-product of urea-selective catalytic reduction (SCR) systems that are being phased-in to control on-road diesel NOx emissions in the United States and the European Union. Given the current levels of exposure in populations that burn biomass or use tobacco, the expected growth in biomass burning emissions with warmer, drier regional climates, and planned increase in diesel SCR controls, it is imperative that we understand the extent and effects of this HNCO exposure.
KW - Heterogeneous chemistry
KW - Troposphere
UR - http://www.scopus.com/inward/record.url?scp=79959330656&partnerID=8YFLogxK
U2 - 10.1073/pnas.1103352108
DO - 10.1073/pnas.1103352108
M3 - Article
C2 - 21576489
AN - SCOPUS:79959330656
SN - 0027-8424
VL - 108
SP - 8966
EP - 8971
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 22
ER -
