TY - JOUR A1 - Newland, M. J. A1 - Martinerie, P. A1 - Witrant, E. A1 - Helmig, D. A1 - Worton, D. R. A1 - Hogan, C. A1 - Sturges, W. T. A1 - Reeves, C. E. T1 - Changes to the chemical state of the Northern Hemisphere atmosphere during the second half of the twentieth century JO - Atmos. Chem. Phys. J1 - ACP VL - 17 IS - 13 SP - 8269 EP - 8283 Y1 - 2017/07/07 PB - Copernicus Publications SN - 1680-7324 UR - https://acp.copernicus.org/articles/17/8269/2017/ L1 - https://acp.copernicus.org/articles/17/8269/2017/acp-17-8269-2017.pdf DO - 10.5194/acp-17-8269-2017 ER -