Changing air quality has been one of the most important drivers of change for bryophytes and lichens in Britain and Ireland over the 20th Century, with acidic pollutants such as sulphur dioxide having large effects on the ranges and abundances of many species. At the same time, expert amateur and professional naturalists have put enormous efforts into recording the distributions of species within these groups. These efforts have provided much evidence for declines and recoveries within the bryophytes and lichens, with species distribution data being linked to airborne pollutants in many different ways. We provide a broad overview of some of the changes that have occurred in affected species, using biological records collected by national recording schemes to illustrate the various effects of air pollution; we also review the direct and indirect impacts of air pollutants on these groups. Environmental change affecting one group of species is also likely to cascade to other groups where trophic or other relationships exist between them. Using data from the volunteer-based National Moth Recording Scheme, we provide the first evidence for an indirect association between reductions in air pollution and increases in lichenivorous moths. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●●, ●●–●●.