Exploratory data analysis of PAH, nitro-PAH and hydroxy-PAH concentrations in atmospheric PM10-bound aerosol particles. Correlations with physical and chemical factors

A method is proposed to determine PAHs, OH-PAHs and nitro-PAHs in samples of PM10 particulate matter based on liquid chromatography with fluorescence detection, and applied to quantify such compounds over a 14-month period in a semiurban area of a large city (Madrid, Spain). A clear seasonal trend was observed in the levels of the compounds. The mean overall concentration of all the PAHs determined was 1250 pg m(-3); with levels rising in the colder months to 2062 pg m(-3) and descending in the warm months to 725 pg m(-3). The same effect was observed for the OH-PAHs, showing a mean of 83 pg m(-3) and values of 153 pg m(-3) and 36 pg m(-3) in the colder and warmer months, and for the nitro-PAHs, with a mean of 132 pg m(-3) and levels of 162 pg m(-3) and of 112 pg m(-3) in the colder and warmer months, respectively. These trends were confirmed in the statistical analysis, which clearly revealed the difference between PAH levels in the months April-September compared to October-December or January-March. Correlations were also found between PAH patterns and those of their hydroxy-and nitro derivatives, as well as between both derivatives. Negative correlation was observed between O-3 and OH-PAH levels and direct correlation between the presence of nitrogen oxides in the atmosphere and nitro-PAHs in the particulate matter. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.