This dataset collection contains ambient concentrations of ClNO2, Cl2, NO3, N2O5, NOx, CO and photolysis rates at the Penlee Point Atmospheric Observatory (UK), University of Leicester campus and Weybourne Atmospheric Observatory (WAO)

This project explores by way of concerted measurements and modelling whether, in the UK context, ClNO2 can release large concentrations of reactive chlorine (Cl) into the troposphere. The chemistry could be especially important for the United Kingdom as the UK is surrounded by the ocean, which provides a continuous source of sea-salt in the coastal areas and further inland. In addition, emissions from coal-fired power stations, spread of grit on roads during winter and usage of chlorinated compounds in swimming pools, sewage and water treatment plants, can provide significant sources of non sea-salt Cl.

The overall objective of this project was to assess the importance of ClNO2 as a chlorine activation pathway and its presence as a strong chlorine source that could affect the composition and oxidative capacity of the atmosphere, with a particular focus on the UK.