GAW Report No. 205 - IGAC Project

CHAPTER 6 - EUROPEair quality in the surrounding areas; Moscow is computed to be the most effective megacityworldwide in exporting pollutants to the boundary layer of regions more than 1000 km downwind[Lawrence et al., 2007]. In certain periods, when meteorological conditions trigger accumulation ofharmful substances in the surface layer, the pollution concentrations may be drastically increased,leading to high pollution episodes. Both summer and winter episodes with high concentrationsoccur frequently in Moscow. One of highest summer pollution episodes in Moscow occurred inSeptember 2002 and was caused by peat fires in the Moscow region [Chubarova et al., 2009].The highest winter pollution episode occurred during February 2006 [Report of the MoscowEnvironment, 2007] when from 3 to 9 February 2006 a combination of weak winds and a cappinginversion layer increased pollutant concentration levels to the highest yet seen. Elevated levels ofair pollution led to the continuous growth of allergic and asthmatic diseases for children and highmortality among elderly population during the summer smog events.Historical trends, connection to political regulations, future prognosisMosEkoMonitoring has established a multiyear database of pollutant concentrations inMoscow that gives the possibility to analyze trends, develop forecasts, and to inform the decisionmaking process. Analysis of air quality monitoring data shows (Figure 20) that in recent years airquality has generally remained at an approximately constant mean level. During the last 10 yearsthe level of air pollution was highest during 2002 (an anomalous year with long-term adverseweather conditions when Moscow was polluted from forest and wood smoke-peat fires in thesurrounding areas). There are modest negative trends in the air concentrations of SO 2 and NO X ,while the CO concentrations have been decreasing continuously and significantly since 2002.Figure 20 - Temporal annual mean concentrations of the main pollutants in Moscow during the years 2002-2008; inthreshold limit values (TLV) for CO, NO2, SO2, O3 and in mg/m 3 for PM10 [Report, 2009]The concentration of total hydrocarbons has remained approximately unchanged since 2004at 1.6-1.7 mg/m 3 for residential areas outside the direct impact of road transport and industrialenterprises and 1.7-1.9 mg/m 3 for areas exposed to vehicle emissions. SO 2 , as an indicator of theuse of reserve fuel types by thermal power plants, in recent years has remained stably low in allareas of the city (average concentrations amounted 0,006 - 0,007 mg/m 3 ). Average concentrationsof PM 10 remained almost unchanged, except for a notable interannual variability. Since 2004 PM 10212