Modelling Past and Future Changes in Secondary Inorganic Aerosol Concentrations in the UK
The FRAME (Fine Resolution Atmospheric Multi-pollutant Exchange) model is a Lagrangian atmospheric transport model with a horizontal grid resolution of 5 × 5 km2. This work uses FRAME to calculate annual average concentrations of three secondary inorganic aerosol species (NH4 +, NO3 −, SO4 2−) and gas phase SO2 over the United Kingdom for the years 2000–2010. Modelled concentrations are compared to measurements from 12 monitoring sites which are operated with the UK Eutrophying and Acidifying Air Pollutants (UKEAP) Acid Gases and Aerosols Network (AGANet). The results showed good spatial correlation between measurements of gas and aerosol concentrations and modelled values (R2 > 0.8). However FRAME underestimated decreases in sulphate and ammonium aerosol concentrations over the 11-year period and overestimated changes in SO2 concentrations relative to measurements. Ongoing work to investigate temporal changes in atmospheric oxidation rates should clarify this difference. FRAME showed a more modest reduction in nitrate concentrations (compared to ammonium and sulphate), which is in agreement with measurements.
FRAME was used to estimate air concentrations for two future scenarios based on emissions predictions for the years 2020 and 2030 in which significant reductions in UK emissions in the UK are forecast (40 % for SO2 and 47 % for NOx between 2010 and 2030). The relationships between long term changes in precursor gas emissions and the formation of secondary inorganic aerosol are discussed in terms of the modelling results.
KeywordsAerosol Concentration Plume Rise Horizontal Grid Resolution Straight Line Trajectory Point Source Emission
- 2.Dore AJ, Vieno M, Tang YS, Dragosits U, Dosio A, Weston KJ, Sutton MA (2007) Modelling the atmospheric transport and deposition of sulphur and nitrogen over the United Kingdom and assessment of the influence of SO2 emissions from international shipping. Atmos Environ 41(11):2355–2367CrossRefGoogle Scholar