Polycyclic aromatic hydrocarbons and hopanes in PM1 aerosols in urban areas

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), 4 hopanes and alpha alpha alpha (20R)-cholestane in PM1 aerosol samples were measured in two cities of the Czech Republic (Brno and Slapanice) in winter and summer season of 2009 and 2010. Daily PM1 aerosol samples were collected on pre-fired quartz fibre filters. Mass concentrations of PM1 aerosols were higher in winter than in summer both in Brno and Slapanice during both 2009 and 2010. The mean total PAH concentrations (Sigma 16 PAHs) in PM1 aerosol was 22.2 ng m(-3) in Brno and 21.0 ng m(-3) in Slapanice during winter period 2009 while the mean total PAH concentrations was 5.01 ng m(-3) in Brno and 5.41 ng m(-3) in Slapanice in summer 2009. In winter 2010, the mean total PAR concentrations was 39.8 ng m(-3) and 38.7 ng m(-3) in Brno and Slapanice whereas, in summer 2010, the mean total PAH concentrations was 1.68 ng m(-3) and 1.52 ng m(-3) at the same localities. The mean total concentrations of four hopanes and a sterane were much smaller than those for PAHs. On the contrary, the difference between the mean total concentrations of hopanes and sterane in winter and summer season was not so large as it was found for PAHs. Analysis of source specific molecular markers and diagnostic ratios of PAHs and hopanes were employed to identify the main emission sources of these compounds. Diagnostic ratios imply that during winter the origin of PAHs was mainly from coal/biomass burning while hopanes originate mainly from coal combustion. During summer season, traffic is proposed as the main emission source of particulate PAHs and hopanes. Organic and elemental carbon were analysed in collected PM1 samples too. Organic carbon contributes significantly to the total mass of PM1 aerosols ranging from 24 to 31% in winter season and from 21 to 29% in summer season. (C) 2012 Elsevier Ltd. All rights reserved.