OH and HO2 Chemistry in the urban atmosphere of New York City
OH and HO2 Chemistry in the urban atmosphere of New York City
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DOI：
10.1016/s1352-2310(03)00459-x
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发表时间：
2003-08
影响因子：
5
通讯作者：
X. Ren;H. Harder;Mónica Martínez;R. Lesher;A. Oliger;J. Simpas;W. Brune;J. Schwab;K. Demerjian-K.-De
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文献类型：
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作者：
X. Ren;H. Harder;Mónica Martínez;R. Lesher;A. Oliger;J. Simpas;W. Brune;J. Schwab;K. Demerjian-K.-De
将观测到的羟基（OH）和羟基（HO2）自由基（统称为HOx）与利用区域大气化学机制的箱形模型计算的OH和HO2进行了比较，该模型受限于2001年夏季在纽约市密集进行的pm2.5技术评估和表征研究-纽约（PMTACS-NY）期间的辅助测量。测量结果见Ren et al. （PMTACS-NY2001期间纽约市的hox浓度和OH反应性观测，大气环境，本期）。这种比较使我们能够研究在这个被污染的城市大气中的化学成分。对于HO2，模式计算通常可以很好地再现观测浓度和日变化，白天和夜间的观测与模型之比平均为1.24。对于OH，该模型通常能够将白天的测量浓度与观测到的与模型的比值匹配在1.10左右，但计算结果明显低估了夜间的OH。hox的预算表明，它的生产主要是HONO的光解作用，平均占hox产量的56%，在白天，由于相对较高的HONO浓度，而夜间hox的生产主要来自与烯烃的o3反应。OH反应度的测量值与计算值的吻合度在10%以内，其复合日变化和单日变化都在10%以内。计算表明，该城区OH与NO2、碳氢化合物、CO、NO和羰基的反应分别约占OH总损失的32%、25%、12%、10%和7%。模拟的ho2和ro2与NO反应的瞬时臭氧产生量为150±100ppbvday−1。在较高的NO值下，实测的HO2（P(O3)obsHO2）生成O3的速率大于模拟的HO2（P(O3)calcHO2）。平均每日累积P(O3) obsho2为~ 140ppbvday−1，比平均每日P(O3)calcHO2大1.5倍。
Observed hydroxyl (OH) and hydroperoxy (HO2) radicals, collectively called HOx, were compared with OH and HO2calculated by a box model that used the regional atmospheric chemistry mechanism and was constrained to the ancillary measurements during the PM2.5Technology 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. (HOxconcentrations and OH reactivity observations in New York City during PMTACS-NY2001, Atmospheric Environment, this issue). This comparison enables an investigation of HOxchemistry 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 HOxshow that its production was dominated by the photolysis of HONO, accounting for ∼56% of HOxproduction on average, during daytime due to relatively high HONO concentrations, while nighttime HOxproduction was mainly from the O3reactions 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 O3production from HO2and RO2reactions with NO was 150±100ppbvday−1. O3production 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)obsHO2was ∼140ppbvday−1, a factor of 1.5, greater than average daily P(O3)calcHO2.