TY - JOUR
T1 - The reaction of Criegee intermediate CH2OO with water dimer
T2 - Primary products and atmospheric impact
AU - Sheps, Leonid
AU - Rotavera, Brandon
AU - Eskola, Arkke J.
AU - Osborn, David L.
AU - Taatjes, Craig A.
AU - Au, Kendrew
AU - Shallcross, Dudley E.
AU - Khan, M. Anwar H.
AU - Percival, Carl J.
PY - 2017
Y1 - 2017
N2 - The rapid reaction of the smallest Criegee intermediate, CH2OO, with water dimers is the dominant removal mechanism for CH2OO in the Earth's atmosphere, but its products are not well understood. This reaction was recently suggested as a significant source of the most abundant tropospheric organic acid, formic acid (HCOOH), which is consistently underpredicted by atmospheric models. However, using time-resolved measurements of reaction kinetics by UV absorption and product analysis by photoionization mass spectrometry, we show that the primary products of this reaction are formaldehyde and hydroxymethyl hydroperoxide (HMHP), with direct HCOOH yields of less than 10%. Incorporating our results into a global chemistry-transport model further reduces HCOOH levels by 10-90%, relative to previous modeling assumptions, which indicates that the reaction CH2OO + water dimer by itself cannot resolve the discrepancy between the measured and predicted HCOOH levels.
AB - The rapid reaction of the smallest Criegee intermediate, CH2OO, with water dimers is the dominant removal mechanism for CH2OO in the Earth's atmosphere, but its products are not well understood. This reaction was recently suggested as a significant source of the most abundant tropospheric organic acid, formic acid (HCOOH), which is consistently underpredicted by atmospheric models. However, using time-resolved measurements of reaction kinetics by UV absorption and product analysis by photoionization mass spectrometry, we show that the primary products of this reaction are formaldehyde and hydroxymethyl hydroperoxide (HMHP), with direct HCOOH yields of less than 10%. Incorporating our results into a global chemistry-transport model further reduces HCOOH levels by 10-90%, relative to previous modeling assumptions, which indicates that the reaction CH2OO + water dimer by itself cannot resolve the discrepancy between the measured and predicted HCOOH levels.
UR - http://www.scopus.com/inward/record.url?scp=85028474533&partnerID=8YFLogxK
U2 - 10.1039/c7cp03265j
DO - 10.1039/c7cp03265j
M3 - Article
AN - SCOPUS:85028474533
SN - 1463-9076
VL - 19
SP - 21970
EP - 21979
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 33
ER -