Research and analysis

Uncertainty in acid deposition modelling and critical load assessment

The results of this study provide a baseline for critical load assessments to assist in the development of a full risk based approach to air quality assessment of processes



The critical loads approach has been developed as an aid to the regulation of acidifying gas emissions, both within the UK and internationally. The critical load is broadly defined as the amount of pollutant deposition a part of the environment can tolerate without harm. Trajectory models such as HARM, TRACK and FRAME have been developed to assess acid deposition to sensitive areas. They use a spatially disaggregated emissions inventory and predict deposition at grid squares throughout the United Kingdom.