Evaluation of Simulated Particulate Matter Spread in 2010 Russian Wildfire Case Using Air Quality Monitoring Data

This study is focused on a wild-land fire episode in 2010, August 7-9, when the plume of severe wildfires in European part of Russia reached Estonia and southern Finland, thus giving a chance to evaluate the modelling results against a relatively dense network of air quality monitoring stations. The chemistry-transport model SILAM, driven by the ECMWF meteo fields, was run within the European domain of AQMEII2 model validaton exercise with a 0.2-degree grid resolution, applying the AQMEII2 chemical and aerosol boundary conditions. The modelling results were compared with measured three-hourly average concentrations of PM2.5 in Estonia and Finland. The observed peak values in most of stations reached 60-80 mu g/m(3) (narrow peaks in the easternmost stations: up to 106 mu g/m(3) in Estonia and 220 mu g/m(3) in Finland, whereas SILAM predicted up to 75 mu g/m(3)). Remarkably enhanced particulate matter concentrations were found in all 7 continental (rural and urban) monitoring stations of Estonia, reproduced by the model within 10 % of the peak values in 5 stations. The general shape of the peak was reproduced by SILAM within 3-6 h of a time error. The model runs suggest that the wildfires were not solely responsible for enhanced concentrations: the continental aerosols constituted about a half of the total mass. The westernmost maritime station in Estonia was left almost untouched by the plume. Remarkable direct effect of the aerosols on boundary-layer meteorological conditions, PBL height, near-surface wind and temperature was found during this episode when the aerosol direct radiative effect was considered in numerical weather prediction model HARMONIE.