Nitrogen Oxides Emissions, Chemistry, Deposition, and Export Over the Northeast United States During the WINTER Aircraft Campaign
Nitrogen Oxides Emissions, Chemistry, Deposition, and Export Over the Northeast United States During the WINTER Aircraft Campaign
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DOI：
10.1029/2018jd029133
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发表时间：
2018-11-16
影响因子：
4.4
通讯作者：
Weber, R. J.
中科院分区：
文献类型：
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作者：
Jaegle, L.;Shah, V.;Weber, R. J.
我们利用2015年2-3月冬季运输、排放和反应调查(冬季)活动中的飞机观测，以及GEOS-Chem化学输送模式和并行地面观测，研究了美国东北部(NE US)对流层低层中氮氧化物(NOx)的分布和去向。我们发现，美国环保局的国家排放清单与冬季观测的总反应氮((NOY)-N-T)平均一致，在10%以内，而过去的研究报告在较温暖的条件下严重高估了这一点。更新了干沉积方案和五氧化二氮(N2O5)反应吸收概率(SIC)(N2O5)，改进了对气相硝酸(HNO3)和亚微米颗粒硝酸盐(PNO(3)(-))的模拟，将冬季HNO3+PNO(3)(-)中2-3高估的长期系数降低到50%的正偏差。我们发现，在美国东北部的对流层下部，NOx的寿命为22小时，以防止化学损失和沉积。NOx的化学损失主要是N2O5的水解(损失的58%)和与OH的反应(33%)，而7%的NOx导致有机硝酸盐的生成。湿沉降和干沉降分别占陆地(NOY)-N-T沉降的55%和45%。我们估计，在冬季，42%的NOx是从美国东北边界层输出的，主要以HNO_3+PNO(3)(-)(40%)和NOx(38%)的形式输出。氮氧化物的命运仍然鲜为人知，特别是在冬季，阳光不足导致它们在大气中持续存在。我们分析了2015年冬季美国东北部上空对氮氧化物及其大气产物的全面飞机观测。这一详细的化学信息有助于解决长期以来对氮氧化物氧化产物的高估问题，并对氮氧化物沉积到陆地生态系统和出口到全球大气层造成新的限制。
We examine the distribution and fate of nitrogen oxides (NOx) in the lower troposphere over the Northeast United States (NE US) using aircraft observations from the Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) campaign in February-March 2015, as well as the GEOS-Chem chemical transport model and concurrent ground-based observations. We find that the National Emission Inventory from the U. S. Environmental Protection Agency is consistent with WINTER observations of total reactive nitrogen ((NOy)-N-T) to within 10% on average, in contrast to the significant overestimate reported in past studies under warmer conditions. Updates to the dry deposition scheme and dinitrogen pentoxide (N2O5) reactive uptake probability, (sic)(N2O5), result in an improved simulation of gas-phase nitric acid (HNO3) and submicron particulate nitrate (pNO(3)(-)), reducing the longstanding factor of 2-3 overestimate in wintertime HNO3 + pNO(3)(-) to a 50% positive bias. We find a NOx lifetime against chemical loss and deposition of 22 hr in the lower troposphere over the NE US. Chemical loss of NOx is dominated by N2O5 hydrolysis (58% of loss) and reaction with OH (33%), while 7% of NOx leads to the production of organic nitrates. Wet and dry deposition account for 55% and 45% of (NOy)-N-T deposition over land, respectively. We estimate that 42% of the NOx emitted is exported from the NE US boundary layer during winter, mostly in the form of HNO3 + pNO(3)(-) (40%) and NOx (38%).Plain Language Summary Nitrogen oxides are a key family of pollutants emitted by cars, electric utilities, and industry. The fate of nitrogen oxides remains poorly understood especially during the winter season, when low sunlight leads to their persistence in the atmosphere. We analyze comprehensive aircraft observations of nitrogen oxides and their atmospheric products over the Northeast United States during winter 2015. This detailed chemical information allows to resolve a long-standing overestimate of the oxidation products of nitrogen oxides and places new constraints on their deposition to land ecosystems and export to the global atmosphere.