Distribution of polycyclic aromatic hydrocarbons in the atmosphere of Hong Kong

Abstract

This paper reports the monitoring results of eleven polycyclic aromatic hydrocarbons (PAHs), four to six-ring, at two urban sites-Central & Western (CW) and Tsuen Wan (TW) in Hong Kong from January to December 2000; and the findings of a study conducted in 2001 of the partitioning of the gaseous and particulate phases of PAHs. The sum of the eleven PAHs under study (sigmaPAHs) was found to range from 6.46 to 38.8 ng m(-3). The annual mean levels at 12.2 ng m(-3) and 15.8 ng m(-3) for CW and TW respectively are comparable to those recorded for the previous two years and are also within the reported ranges for other metropolitan cities in the Asia Pacific region. Amongst the selected eleven PAHs, fluoranthene and pyrene were the two most abundant found in the urban atmosphere of Hong Kong during the study period accounting for approximately 80%, of the total PAHs. The ratios of benzo(a)pyrene to benzo(g,h,i)perylene (BaP/BghiP) and indeno(1,2,3-cd)pyrene to benzo(g,h,i)perylene (IDP/BghiP) indicate that diesel and gasoline vehicular exhausts were the predominant local emission sources of PAHs. Seasonal variations with high winter to summer ratios for each of the individual PAHs (CW: 1.6-16.7 and TW: 0.82-8.2) and for sigmaPAHs (CW: 1.9 and TW: 1.8) and a spatial variation of BaP amongst the air monitoring stations are noted. Results of correlation studies illustrate that local meteorological conditions such as ambient temperature, solar radiation, wind speed and wind direction have significant impact on the concentrations of atmospheric PAHs accounting for the observed seasonal variations. A snapshot comparison of the concentrations of PAHs at four sites including a roadside site, a rural site and the two regular urban sites CW and TW was also performed using the profiles of PAHs recorded on two particulate episode days in March 2000.

Seasonal and Spatial Variation of Solvent Extractable Organic Compounds in Fine Suspended Particulate Matter in Hong Kong

“…Individual PAHs are typically higher in winter than in summer. Such seasonal variation agrees well with the earlier findings 30 on the distribution of 11 4-to-6 ring PAHs at the two urban sites (Central and Western District and Tsuen Wan) in Hong Kong from January to December 2000. Seasonal variation also has been observed with winter maxima for other volatile and semi-volatile organic pollutants in Hong Kong.…”

Gas–particle concentration, distribution, and health risk assessment of polycyclic aromatic hydrocarbons at a traffic area of Giza, Egypt

“…High ambient temperature could change the distribution of PAH compounds between the particulate and gaseous phases by increasing the vapor pressure of these pollutants that adhered to particulate matter in the atmosphere and favoring the volatilization of PAHs from the particulate to gaseous phase (Sin et al 2003). Although high atmospheric temperature increases the conversion of PAH compounds from particulate to gaseous phase, the levels of PAHs in gaseous phase in the present study decreased from winter to summer and also with increasing temperature (Fig.…”

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM2.5 and PM10 at a coal-based industrial city: Implication for PAH control at industrial agglomeration regions, China

“…For their control through air quality management, guided levels of BaP in the USA (Ravindra et al, 2008), European Union (Hien et al, 2007;Ravindra et al, 2008), UK (Sin et al, 2003;Hien et al, 2007), Italy (Sin et al, 2003), WHO (WHO, 2002) and China (MEP, 2012) have been set. However these standard levels are set for a whole city or region without considering different urban sites and the particle size.…”