Abstract The aerosol direct feedback effects (ADFEs) are neglected in traditional air quality modeling studies (where meteorology is used as input and not affected by the chemistry and aerosol microphysics) for estimating the impacts of aircraft emissions on air quality. In this study, aircraft landing and take-off (LTO) attributable change of O3 and PM2.5 concentrations through ADFEs for the year 2005 within the contiguous United States (CONUS) are quantified by a coupled meteorology-chemistry modeling system: Weather Research and Forecasting – Community Multi-scale Air Quality (WRF-CMAQ) model. We first quantified the effects of ADFEs of all aerosols within the CONUS (not the effects of aircraft LTO emissions) on surface meteorology and air quality and found that ADFEs changed on average the downward short-wave radiation (SWR), 2-m temperature (T2), planetary boundary layer (PBL) height, O3 and PM2.5 by −7.38 W/m2, −0.47 K, −20.72 m, −0.41 ppb and +0.28 μg/m3 in 2005. We also found a seasonal influence where ADFE-influenced change (decrease) of SWR, T2, PBL, O3 and change (increase) of PM2.5 were higher in summer than in winter. We found that the aircraft LTO emissions’ contribution to domain average surface concentration of O3 and PM2.5 were +0.0065 ppb and +0.0022 μg/m3 respectively when ADFEs are accounted for. The ADFEs decrease aircraft LTO attributable surface O3 and PM2.5 change by 21% and 23% respectively comparing with that without ADFE in 2005. We also found that in both without-and-with ADFE cases, the aircraft LTO emissions increases domain average of O3 from April to October and decreases from November to March showing a strong seasonal pattern. Our modeling study revealed that use of a coupled model with ADFE shows localized changes in air quality by aircraft LTO emissions across the domain which were masked when looking at domain averages for both O3 and PM2.5, and which may be important for accurately quantifying health risk due to air pollution exposures in densely populated areas.

中文翻译：

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WRF-CMAQ耦合模型估计的气溶胶直接反馈效应对飞机着陆和起飞排放对地表O3和PM2.5的影响

摘要 气溶胶直接反馈效应 (ADFE) 在传统的空气质量建模研究中被忽略（其中气象学被用作输入，不受化学和气溶胶微物理学的影响）来估计飞机排放对空气质量的影响。在这项研究中，2005 年美国本土 (CONUS) 内通过 ADFE 的飞机着陆和起飞 (LTO) 可归因的 O3 和 PM2.5 浓度变化通过气象-化学耦合建模系统进行量化：Weather Research and预测 – 社区多尺度空气质量 (WRF-CMAQ) 模型。我们首先量化了美国本土所有气溶胶的 ADFE（不是飞机 LTO 排放的影响）对地表气象和空气质量的影响，发现 ADFE 平均改变了向下的短波辐射 (SWR)，2 米温度 (T2)、行星边界层 (PBL) 高度、O3 和 PM2.5，2005 年为 -7.38 W/m2、-0.47 K、-20.72 m、-0.41 ppb 和 +0.28 μg/m3。我们还发现季节性影响，ADFE 影响的 SWR、T2、PBL、O3 和 PM2.5 的变化（增加）在夏季高于冬季。我们发现，当考虑 ADFE 时，飞机 LTO 排放对 O3 和 PM2.5 域平均表面浓度的贡献分别为 +0.0065 ppb 和 +0.0022 μg/m3。与 2005 年没有 ADFE 的情况相比，ADFEs 使飞机 LTO 归因表面 O3 和 PM2.5 变化分别降低了 21% 和 23%。我们还发现，在没有和有 ADFE 的情况下，飞机 LTO 排放增加了域平均值O3 从 4 月到 10 月，从 11 月到 3 月减少，呈现出强烈的季节性模式。