Table 1.

Mean concentration (mg/kg) of polycyclic aromatic hydrocarbons (PAHs) and nitro-substituted PAHs (nitro-PAHs) detected in the PM_2.5 samples.

PAHs	Mass Fraction (mg/kg)	Nitro-PAHs	Mass Fraction (mg/kg)
2-Methylphenanthrene	2.22 ± 0.21	9-Nitrophenanthrene	0.466 ± 0.013
1-Methylphenanthrene	0.923 ± 0.057	3-Nitrophenanthrene	0.190 ± 0.007
Triphenylene	5.32 ± 0.24	2-Nitrofluoranthene	0.231 ± 0.032
Benzo[j]fluoranthene	0.819 ± 0.093	3-Nitrofluoranthene	3.80 ± 0.24
Benzo[a]fluoranthene	0.066 ± 0.007	1-Nitropyrene	35.2 ± 2.2
Dibenz[a]anthracene	0.523 ± 0.047	7-Nitrobenz[a]anthracene	3.57 ± 0.32
Picene	0.902 ± 0.091	6-Notrochrysene	2.45 ±0.33
Dibenzo[a,e]pyrene	0.599 ± 0.024
Dibenzo[b,k]fluoranthene	2.54 ± 0.08