The concentrations, behaviour and fate of polycyclic aromatic hydrocarbons (PAHs) and their oxygenated and nitrated derivatives in the urban atmosphereud

摘要

Polycyclic aromatic hydrocarbons (PAHs) play an important role in urban air quality due to the toxic and carcinogenic hazard they present. A class of pollutants receiving increasing interest from researchers are oxygenated (OPAH) and nitrated (NPAH) derivative compounds. There is a need for an improved understanding of the sources, concentrations, behaviour and fate of these pollutants as they can pose a similar public health risk as PAHs and can enter the environment both from primary combustion emissions and secondary formation from atmospheric reactions. This study investigates the airborne concentrations of PAH, OPAH and NPAH compounds in U.K. atmosphere at heavily trafficked and urban background sites. Sampling campaigns were conducted to assess the spatial and temporal trends, primary and/or secondary sources, gas-particle phase partitioning and atmospheric degradation of PAHs, NPAHs and OPAHs. Differences in atmospheric concentrations between trafficked sites and the urban background site indicate a variable influence of road traffic emissions between different PAH, OPAH and NPAH compounds. Seasonal, diurnal and temporal patterns as well as positive matrix factorisation (PMF) source apportionment provide evidence of the key influencing factors governing the concentrations of PAHs, OPAHs and NPAHs in the urban atmosphere, in addition to the strength of road trafficudemissions.