Influence of vehicle population on atmospheric levels of carcinogenic polycyclic aromatic hydrocarbons

Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation (LRAT) to the level of PAHs in the rural atmosphere of Whitbourne,UK.In general,higher R-values coupled with lower P-values were found in those samples within a radius of 300 miles,whereas lower R-values were detected in those samples within a radius of 60 miles.R-values of PAH concentrations vs.all vehicle numbers within radius of 300 miles ranged from 0.51 to 0.92 with the arithmetic mean of 0.75 ± 0.12,whilst those R-values within a radius of 60 miles ranged from 0.05 to 0.61 with the arithmetic mean of 0.11 ± 0.28.This supports the hypothesis that PAHs in Whitbourne undergo LRAT.     

Atmospheric lifetimes and traveling distances of airborne carcinogenic polycyclic aromatic hydrocarbons

Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthrene,Ret:retene,B[a]A:benzo[a]anthracene,Chry:chrysene,B[b,j,k]F:benzo[b,j,k]fluoranthene,B[e]P:benzo[e]pyrene,B[a]P:benzo[a]pyrene,Ind:indeno[1,2,3-cd]pyrene,B[g,h,i]P:benzo[g,h,i]perylene)at Whitbourne,UK,were estimated by using the rate constants for reaction with OH,O3,and the first order rate constants of eight species of high molecular weight PAHs(i.e.B[a]A,Chry,B[b]F,B[k]F,B[a]P,Ind,B[g,h,i]P and Ret)as a function of humidity,solar intensity and temperature by using Multiple Regression Analysis.The predicted atmospheric lifetime of Ac,Ace,Ph,MePh3,MePh9,MePh2 and MePh1 ranged between 11.42 h-79.12 h in cold period and 1/31 h-14.33 h in warm period respectively.The binary ratios of atmospheric lifetime of B[k]F/B[g,h,i]P,B[k]F/B[g,h,i]P,B[g,h,i]P/Ind and B[k]F/Ind displayed non-significant differences between cold and warm period,indicating that high molecular weight PAHs are difficult to be decomposed by UV light and thus may be conveyed to the rural regions via long range atmospheric transportation(LRAT).The decreased level of the atmospheric lifetime of low molecular weight PAHs in summer can be attributed to an increased level of OH radical content and solar radiation.