TY - JOUR A1 - Yao, X. A1 - Zhang, L. T1 - Trends in atmospheric ammonia at urban, rural, and remote sites across North America JO - Atmos. Chem. Phys. J1 - ACP VL - 16 IS - 17 SP - 11465 EP - 11475 Y1 - 2016/09/14 PB - Copernicus Publications SN - 1680-7324 UR - https://acp.copernicus.org/articles/16/11465/2016/ L1 - https://acp.copernicus.org/articles/16/11465/2016/acp-16-11465-2016.pdf DO - 10.5194/acp-16-11465-2016 ER -