Data to support: Anthropogenic influence on tropospheric reactive bromine since the pre-industrial: Implications for ice-core bromine trends

<p>Tropospheric reactive bromine (Br_y) influences the oxidation capacity of the atmosphere by acting as a sink for ozone and nitrogen oxides. Aerosol acidity plays a crucial role in Br_y abundances through acid-catalyzed debromination from sea-salt-aerosol, the largest global source. Bromine concentrations in a Russian Arctic ice-core, Akademii Nauk, show a 3.5-fold increase from pre-industrial (PI) to the 1970s (peak acidity, PA), and decreased by half to 1999 (present day, PD). Ice-core acidity mirrors this trend, showing robust correlation with bromine, especially after 1940 (<em>r</em>=0.9). Model simulations considering anthropogenic emission changes alone show that atmospheric acidity is the main driver of Br_y changes, consistent with the observed relationship between acidity and bromine. The influence of atmospheric acidity and Br_y should be considered in interpretation of ice-core bromine trends.</p>