The merit of David Fowler’s work lies in his quantitative approach to understanding the physical, chemical and biological processes which regulate the land–atmosphere exchange of gaseous and particulate pollutants (SO2, NH3, O3, NO, NO2, HNO3, CH4, N2O, aerosols and cloud droplets) and their effects on vegetation. Development of innovative methods to measure surface–atmosphere exchange at the landscape scale, and application of process-based models to quantify fluxes at the country scale, have been important focuses. The work has been widely applied in the development of effects-based pollution control strategies in the United Kingdom and elsewhere in Europe.