TY - JOUR
T1 - OH and HO2 chemistry in the urban atmosphere of New York City
AU - Ren, Xinrong
AU - Harder, Hartwig
AU - Martinez, Monica
AU - Lesher, Robert L.
AU - Oliger, Angelique
AU - Simpas, James B.
AU - Brune, William H.
AU - Schwab, James J.
AU - Demerjian, Kenneth L.
AU - He, Yi
AU - Zhou, Xianliang
AU - Gao, Honglian
N1 - Funding Information:
The authors thank all other participants in the PMTACS-NY2001 field campaign for use of their data in the model and Kenneth Demerjian for asking us to participate in PMTACS-NY2001. Terry Shirley and Jennifer Adams, who were supported by NSF Research Experience for Undergraduate grants, did a terrific job in the field measurements. Two anonymous reviewers are acknowledged for providing insightful comments and suggestions. This work was supported by NSF (ATM-9974335 and ATM-0209972), the New York State Energy Research and Development Authority (NYSERDA) (contract #4918ERTERES99), the US Environmental Protection Agency (EPA) (cooperative agreement #R828060010), and New York State Department of Environmental Conservation (NYS DEC) (contract #C004210). Although the research described in this article has been funded in part by the US Environmental Protection Agency, it has not been subjected to the Agency's required peer and policy review and therefore does not necessary reflect the views of the Agency and no official endorsement should be inferred.
PY - 2003/8
Y1 - 2003/8
N2 - Observed hydroxyl (OH) and hydroperoxy (HO2) radicals, collectively called HOx, were compared with OH and HO2 calculated by a box model that used the regional atmospheric chemistry mechanism and was constrained to the ancillary measurements during the PM2.5 Technology Assessment and Characterization Study-New York (PMTACS-NY) summer 2001 intensive in New York City. The measurements are described in the companion paper, Ren et al. (HOx concentrations and OH reactivity observations in New York City during PMTACS-NY2001, Atmospheric Environment, this issue). This comparison enables an investigation of HOx chemistry in this polluted urban atmosphere. For HO2, the observed concentrations and diurnal variation were usually well reproduced by the model calculations, with an observed-to-modeled ratio of 1.24, on average, for day and night. For OH, the model was generally able to match the measured concentrations during daytime with an observed-to-modeled ratio of about 1.10, but the calculations significantly underestimated OH during nighttime. The budgets of HOx show that its production was dominated by the photolysis of HONO, accounting for ∼56% of HOx production on average, during daytime due to relatively high HONO concentrations, while nighttime HOx production was mainly from the O3 reactions with alkenes. The OH reactivity measurements agree with the calculations to within 10% for both the composite diurnal variation and individual days. Calculations indicate that the reactions of OH with NO2, hydrocarbons, CO, NO, and carbonyls accounted for about 32%, 25%, 12%, 10% and 7% of total OH loss, respectively, in this urban area. Modeled instantaneous O3 production from HO2 and RO2 reactions with NO was 150±100ppbvday-1. O3 production rates from measured HO2(P(O3)obsHO2) was greater than modeled HO2(P(O3)calcHO2) at higher values of NO. Average daily cumulative P(O3)obsHO2 was ∼140ppbvday-1, a factor of 1.5, greater than average daily P(O3)calcHO2.
AB - Observed hydroxyl (OH) and hydroperoxy (HO2) radicals, collectively called HOx, were compared with OH and HO2 calculated by a box model that used the regional atmospheric chemistry mechanism and was constrained to the ancillary measurements during the PM2.5 Technology Assessment and Characterization Study-New York (PMTACS-NY) summer 2001 intensive in New York City. The measurements are described in the companion paper, Ren et al. (HOx concentrations and OH reactivity observations in New York City during PMTACS-NY2001, Atmospheric Environment, this issue). This comparison enables an investigation of HOx chemistry in this polluted urban atmosphere. For HO2, the observed concentrations and diurnal variation were usually well reproduced by the model calculations, with an observed-to-modeled ratio of 1.24, on average, for day and night. For OH, the model was generally able to match the measured concentrations during daytime with an observed-to-modeled ratio of about 1.10, but the calculations significantly underestimated OH during nighttime. The budgets of HOx show that its production was dominated by the photolysis of HONO, accounting for ∼56% of HOx production on average, during daytime due to relatively high HONO concentrations, while nighttime HOx production was mainly from the O3 reactions with alkenes. The OH reactivity measurements agree with the calculations to within 10% for both the composite diurnal variation and individual days. Calculations indicate that the reactions of OH with NO2, hydrocarbons, CO, NO, and carbonyls accounted for about 32%, 25%, 12%, 10% and 7% of total OH loss, respectively, in this urban area. Modeled instantaneous O3 production from HO2 and RO2 reactions with NO was 150±100ppbvday-1. O3 production rates from measured HO2(P(O3)obsHO2) was greater than modeled HO2(P(O3)calcHO2) at higher values of NO. Average daily cumulative P(O3)obsHO2 was ∼140ppbvday-1, a factor of 1.5, greater than average daily P(O3)calcHO2.
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U2 - 10.1016/S1352-2310(03)00459-X
DO - 10.1016/S1352-2310(03)00459-X
M3 - Article
AN - SCOPUS:0038690382
SN - 1352-2310
VL - 37
SP - 3639
EP - 3651
JO - Atmospheric Environment
JF - Atmospheric Environment
IS - 26
ER -