Open AccessComparison of daytime and nighttime oxidation of biogenic and anthropogenic VOCs along the New England coast in summer during New England Air Quality Study 2002
Author(s) -
Warneke C.,
de Gouw J. A.,
Goldan P. D.,
Kuster W. C.,
Williams E. J.,
Lerner B. M.,
Jakoubek R.,
Brown S. S.,
Stark H.,
Aldener M.,
Ravishankara A. R.,
Roberts J. M.,
Marchewka M.,
Bertman S.,
Sueper D. T.,
McKeen S. A.,
Meagher J. F.,
Fehsenfeld F. C.
Publication year - 2004
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jd004424
Subject(s) - isoprene , methacrolein , methyl vinyl ketone , environmental science , environmental chemistry , daytime , ozone , nox , morning , air quality index , chemistry , atmospheric sciences , meteorology , geology , organic chemistry , geography , medicine , monomer , copolymer , catalysis , combustion , methacrylic acid , polymer
Volatile organic compounds (VOCs) and some of their oxidants (O 3 , NO 3 ) were measured on board the National Oceanic and Atmospheric Administration research ship R/V Ronald H. Brown along the coast of New England, downwind of New York, Boston, and Portsmouth and large forested areas in New Hampshire, Maine, and Massachusetts in July and August 2002. The diurnal variations of isoprene, monoterpenes, and aromatics were mainly dependent on their emissions and the abundance of the oxidants OH and NO 3 . Elevated mixing ratios of short‐lived VOCs were only encountered at the ship, which was about 1–6 hours downwind of the sources, when the concentrations of the oxidants were low. For the biogenic compounds this was generally the case during morning and evening hours, when the lifetime of the biogenics was long because of low OH and NO 3 concentrations. Most anthropogenic VOCs do not react with NO 3 , and therefore their mixing ratios remained elevated during the night. The products of isoprene oxidation, methyl vinyl ketone, methacrolein, and peroxymethacrylic nitric anhydride (MPAN) were, on average, more abundant than isoprene itself. Only during the transition periods from day to night, when oxidation rates were at a minimum, could isoprene exceed its products. The loss of the biogenic VOCs was dominated by reactions with NO 3 , whereas the loss of anthropogenics came mostly from reactions with OH. The oxygenated VOCs are the major contributor to the OH loss, except in close vicinity of emission sources. The total loss of biogenic compounds during the night was so effective that after one night of transport they were in most cases completely reacted away, whereas the mixing ratios of the anthropogenic compounds remained high during the night. The pool of reactive hydrocarbons at sunrise was thus typically dominated by anthropogenic VOCs.