PM measurement campaign HOVERT in the Greater Berlin area: model evaluation with chemically specified particulate matter observations for a one year period

Abstract

Abstract. The HOVERT (HOrizontal and VERtical Transport of ozone and particulate matter) campaign held in the Berlin Brandenburg area in Eastern Germany from September 2001 to September 2002 allowed to collect a unique data set of the aerosol chemical speciation (daily averages) at traffic, urban and rural sites. These observations are used for a thorough evaluation of the aerosol part in the REM-CALGRID model (RCG) developed at the Free University of Berlin (FUB). For inorganic ions (sulphate, nitrate and ammonium), simulated annual averages agree to observations within ±30% at more than half of the sites and always within a factor of two. Correlation coefficients are larger than in previous studies for SO 2− 4 and NH + 4 (>0.7). For nitrate, less elevated correlations, 0.4-0.7 in the cold season, 0.2-0.4 in the warm season, are encountered. To our knowledge, this is one of the first comparisons of air quality model simulated elemental and organic carbon (EC and OC) with daily observations for a whole year. It suggests an overestimation of EC and OC emissions in the Berlin area (through a scaling techniques between EC, OC and NO x and when assuming correct NO x emissions), and an underestimation of EC and OC at rural sites. Secondary organic aerosol (SOA) formation, recently introduced into the model (SORGAM module, Schell et al., 2001), is simulated as a very variable process, SOA levels varying from close to zero for most days to more than 5 µg/m 3 . Correlation between simulated SOA to observed OC is about 0.6, indicating that simulated variability partly corresponds to reality.

Measurements and simulation of speciated PM2.5 in south-west Europe

“…In this study, the highest sulphate concentrations were observed during the wintertime campaign; the mean concentration at University Campus Poorer performance for sulphate episodes in wintertime compared to summertime has been documented in other studies (e.g. Beekmann et al, 2007;Schaap et al, 2011;Pay et al, 2011), and may in part be due to difficulties in the meteorological simulation of these winter-time pollution episodes as well as issues of oxidant availability.…”

“…Baker and Scheff, 2007;Tesche et al, 2006;Gaydos et al, 2007;Mathur et al, 2008) using large scale measurement networks for their evaluation. There have been various modelling studies in Europe including comparisons with measured speciated aerosol such as Lazaridis et al (2005), Beekmann et al (2007), Chemel et al (2010), Renner and Wolke (2010), Lonati et al (2010), Andreani-Aksoyoglu et al (2011), Schaap et al (2011), Basart et al (2012) and Pay et al (2011). The modelling performance reported depends on component, season and location but the majority of these studies have reported an underestimation of observed concentrations.…”

Impact of emission changes on secondary inorganic aerosol episodes across Germany

“…The Eulerian grid model REM-Calgrid (RCG) simulates air pollution concentrations solving the advection-diffusion equation on a regular latitude-longitude-grid with variable resolution over Europe (Beekmann et al, 2007;Stern, 2006). RCG is offline-coupled to the German Weather Service operational NWP model COSMO-EU (Schättler et al, 2008).…”

Elevated PM10 and PM2.5 concentrations in Europe: a model experiment with MM5-CMAQ and WRF-CHEM

“…The EC fraction of the PM2.5 emissions for the different SNAP sectors were taken from [19]. For the OC fraction, the method proposed by [20] is applied as follows: an average OC/EC emission ratio of two was used for all sectors, i.e. the OC fraction were set as twice the EC fractions, except if the sum of the two fractions exceed the unity.…”