TY - JOUR
T1 - Long-term (2005–2014) trends in formaldehyde (HCHO) columns across North America as seen by the OMI satellite instrument
T2 - Evidence of changing emissions of volatile organic compounds
AU - Zhu, Lei
AU - Mickley, Loretta J.
AU - Jacob, Daniel J.
AU - Marais, Eloïse A.
AU - Sheng, Jianxiong
AU - Hu, Lu
AU - Abad, Gonzalo González
AU - Chance, Kelly
N1 - Publisher Copyright:
©2017. The Authors.
PY - 2017/7/16
Y1 - 2017/7/16
N2 - Satellite observations of formaldehyde (HCHO) columns provide top-down information on emissions of highly reactive volatile organic compounds (VOCs). We examine the long-term trends in HCHO columns observed by the Ozone Monitoring Instrument from 2005 to 2014 across North America. Biogenic isoprene is the dominant source of HCHO, and its emission has a large temperature dependence. After correcting for this dependence, we find a general pattern of increases in much of North America but decreases in the southeastern U.S. Over the Houston-Galveston-Brazoria industrial area, HCHO columns decreased by 2.2% a−1 from 2005 to 2014, consistent with trends in emissions of anthropogenic VOCs. Over the Cold Lake Oil Sands in the southern Alberta in Canada, HCHO columns increased by 3.8% a−1, consistent with the increase in crude oil production there. HCHO variability in the northwestern U.S. and Midwest could be related to afforestation and corn silage production. Although NOx levels can affect the HCHO yield from isoprene oxidation, we find that decreases in anthropogenic NOx emissions made only a small contribution to the observed HCHO trends.
AB - Satellite observations of formaldehyde (HCHO) columns provide top-down information on emissions of highly reactive volatile organic compounds (VOCs). We examine the long-term trends in HCHO columns observed by the Ozone Monitoring Instrument from 2005 to 2014 across North America. Biogenic isoprene is the dominant source of HCHO, and its emission has a large temperature dependence. After correcting for this dependence, we find a general pattern of increases in much of North America but decreases in the southeastern U.S. Over the Houston-Galveston-Brazoria industrial area, HCHO columns decreased by 2.2% a−1 from 2005 to 2014, consistent with trends in emissions of anthropogenic VOCs. Over the Cold Lake Oil Sands in the southern Alberta in Canada, HCHO columns increased by 3.8% a−1, consistent with the increase in crude oil production there. HCHO variability in the northwestern U.S. and Midwest could be related to afforestation and corn silage production. Although NOx levels can affect the HCHO yield from isoprene oxidation, we find that decreases in anthropogenic NOx emissions made only a small contribution to the observed HCHO trends.
KW - HCHO
KW - Ozone Monitoring Instrument
KW - trend
UR - http://www.scopus.com/inward/record.url?scp=85023630281&partnerID=8YFLogxK
U2 - 10.1002/2017GL073859
DO - 10.1002/2017GL073859
M3 - Article
AN - SCOPUS:85023630281
SN - 0094-8276
VL - 44
SP - 7079
EP - 7086
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 13
ER -