含氮气体在海盐表面的非均相反应对中国近海大气氮干沉降的影响

Impacts of Heterogeneous Reactions of Nitrogen-Containing Gases on Sea Salts on Nitrogen Dry Deposition Fluxes over the China Sea

通过改进WRF-CMAQ大气化学传输模型的非均相反应模块,模拟了2014年春季(4月28日~5月18日)中国东部沿海和近海海域大气中含氮物质的浓度和干沉降通量,分析了含氮气体在海盐表面的非均相反应过程对含氮物质浓度、相态分配和干沉降通量的贡献。模拟结果表明,海盐表面含氮气体的非均相反应使得渤海、黄海、东海等近海海域大气中NO 2、N 2O 5、HNO 3气体向粗颗粒NO-3(NO-3 coarse)转化,模拟期间三种气体平均浓度分别降低了0.4%~5.2%、4.7%~18.2%和9.2%~15.6%,NO-3 coarse平均浓度增加了25.3%~35.1%;受含氮物质相态变化的影响,总无机氮日均干沉降通量在渤黄东海大气中增加了1.5%~3.7%,其中NO-3 coarse日均干沉降通量增加27.6%~52.4%,而HNO 3和N 2O 5气体日均干沉降通量分别减少9.6%~16.0%和12.3%~23.9%。污染天气条件下,总无机氮干沉降受非均相反应的影响较干洁天气更加显著,渤海、黄海、东海总无机氮日均干沉降通量可提高4.2%~17.1%,分别为干洁天气条件下的2.3、2.9和1.9倍。

By using the WRF-CMAQ model improved the heterogeneous module,the concentrations and dry deposition fluxes of nitrogen-containing compounds in the coastal and offshore of China from April 28 to May 18,2014 are simulated.And the contribution of heterogeneous reactions between nitrogen-containing gases and sea salts to the concentrations of nitrogen-containing compounds,phase distribution and dry deposition fluxes are quantitatively analyzed.The results show that heterogeneous reactions make NO 2,N 2O 5 and HNO 3 gases transform into coarse-mode NO-3 in atmosphere of the China Sea,and the concentrations of three gases reduce by 0.4%~5.2%,4.7%~18.2%and 9.2%~15.6%,respectively.The concentration of coarse-mode NO-3 increase by 25.3%~35.1%.Affected by changes in phase distribution of nitrogen-containing compounds,the dry deposition flux of total inorganic nitrogen increase by 1.5%~3.7%,of which coarse-mode NO-3 increase by 27.6%~52.4%while HNO 3 and N 2O 5 reduce by 9.6%~16.0%and 12.3%~23.9%.Dry deposition flux of total inorganic nitrogen in the Bohai Sea,the Yellow Sea and the East China Sea increase by 4.2%~17.1%in periods of pollution weather,which is 2.3,2.9 and 1.9 times as much as that in clean weather.