Temporal characteristics of atmospheric ammonia and nitrogen dioxide over China based on emission data, satellite observations and atmospheric transport modeling since 1980

摘要

China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen (Nsubr/sub). Atmospheric ammonia (NHsub3/sub) and nitrogen dioxide (NOsub2/sub) are the most important precursors for Nsubr/sub compounds (including Nsub2/subOsub5/sub, HNOsub3/sub, HONO and particulate NOsub3/subsup?/sup and NHsub4/subsup+/sup) in the atmosphere. Understanding the changes in NHsub3/sub and NOsub2/sub has important implications for the regulation of anthropogenic Nsubr/sub emissions and is a requirement for assessing the consequence of environmental impacts. We conducted the temporal trend analysis of atmospheric NHsub3/sub and NOsub2/sub on a national scale since 1980 based on emission data (during 1980–2010), satellite observation (for NHsub3/sub since 2008 and for NOsub2/sub since 2005) and atmospheric chemistry transport modeling (during 2008–2015).brbrBased on the emission data, during 1980–2010, significant continuous increasing trends in both NHsub3/sub and NOsubix/i/sub were observed in REAS (Regional Emission inventory in Asia, for NHsub3/sub 0.17 and for NOsubix/i/sub 0.16?kg?N?hasup?1/sup?yrsup?2/sup) and EDGAR (Emissions Database for Global Atmospheric Research, for NHsub3/sub 0.24 and for NOsubix/i/sub 0.17?kg?N?hasup?1/sup?yrsup?2/sup) over China. Based on the satellite data and atmospheric chemistry transport model (CTM) MOZART-4 (Model for Ozone and Related chemical Tracers, version 4), the NOsub2/sub columns over China increased significantly from 2005 to 2011 and then decreased significantly from 2011 to 2015; the satellite-retrieved NHsub3/sub columns from 2008 to 2014 increased at a rate of 2.37?%?yrsup?1/sup. The decrease in NOsub2/sub columns since 2011 may result from more stringent strategies taken to control NOsubix/i/sub emissions during the 12th Five Year Plan, while no control policy has focused on NHsub3/sub emissions. Our findings provided an overall insight into the temporal trends of both NOsub2/sub and NHsub3/sub since 1980 based on emission data, satellite observations and atmospheric transport modeling. These findings can provide a scientific background for policy makers that are attempting to control atmospheric pollution in China. Moreover, the multiple datasets used in this study have implications for estimating long-term Nsubr/sub deposition datasets to assess its impact on soil, forest, water and greenhouse balance.