Currently, in operational modelling of NH 3 deposition a fixed value of canopy resistance (R c ) is generally applied, irrespective of the plant species and NH 3 concentration. This study determined the effect of NH 3 concentration on deposition processes to individual moorland species. An innovative flux chamber system was used to provide accurate continuous measurements of NH 3 deposition to Deschampsia cespitosa (L.) Beauv., Calluna vulgaris (L.) Hull, Eriophorum vaginatum L., Cladonia spp., Sphagnum spp., and Pleurozium schreberi (Brid.) Mitt. Measurements were conducted across a wide range of NH 3 concentrations (1–140μgm −3 ).NH 3 concentration directly affects the deposition processes to the vegetation canopy, with R c , and cuticular resistance (R w ) increasing with increasing NH 3 concentration, for all the species and vegetation communities tested. For example, the R c for C. vulgaris increased from 14sm −1 at 2μgm −3 to 112sm −1 at 80μgm −3 . Diurnal variations in NH 3 uptake were observed for higher plants, due to stomatal uptake; however, no diurnal variations were shown for non-stomatal plants. R c for C. vulgaris at 80μgm −3 was 66 and 112sm −1 during day and night, respectively. Differences were found in NH 3 deposition between plant species and vegetation communities: Sphagnum had the lowest R c (3sm −1 at 2μgm −3 to 23 at 80μgm −3 ), and D. cespitosa had the highest nighttime value (18sm −1 at 2μgm −3 to 197sm −1 at 80μgm −3 ).