Objectives

The OMO measurement campaign aims to determine the rates at which natural and human‐made compounds are converted by oxidation processes in the atmosphere, which in turn affect the lifetime and the global distribution of many air pollutants and greenhouse gases, including aerosol particles and tropospheric ozone (O₃). A central question is to what extent the self‐cleaning mechanism is “stressed” by the enormous and growing emissions of contaminants. HALO measures reactive species, including radicals, and quantify the major chemical sources and sinks to evaluate models, focusing on the following aspects:

1) Oxidation processes and free radical chemistry;

2) Efficiency of convective cloud transport and wet deposition,

3) Long‐distance transport of air pollution;

4) Impacts on air quality and climate change.

The measurements are performed during the summer monsoon (July/Aug 2015) when convective cloud transport, rainfall and photochemistry are most intense.