PM	particulate matter
US EPA	US Environmental Protection Agency
PAHs	polycyclic aromatic hydrocarbons
VOCs	volatile organic compounds
CCA	canonical correspondence analysis
OPLS-DA	orthogonal partial least squares discriminant analysis
·OH	hydroxyl radicals
EPR	electron paramagnetic resonance
CNEMC	China National Environmental Monitoring Centre
PCR	polymerase chain reaction
Operational taxonomic units	OTUs
RDP	Ribosomal Database Project
DMPO	5,5-dimethyl-1-pyrroline-N-oxide
HQ	hazard quotient
CR	carcinogenic risk
SF	slope factor
AF	dermal adherence factors
ABS	dermal absorption factor
SA	skin area
ED	exposure duration
EF	exposure frequency
BW	body weight
AT	averaging time
NaP	naphthalene
Acy	acenaphthylene
Acen	acenaphthene
Fl	fluorene
Phe	phenanthrene
Ant	anthracene
Flu	fluoranthene
Pyr	pyrene
BaA	benzo[a]anthracene
Chr	chrysene
BbF	benzo[b]fluoranthene
BkF	benzo[k]fluoranthene
BaP	benzo[a]pyrene
InP	indeno[1,2,3-cd]pyrene
DbA	dibenzo[a,h]anthracene
BgP	benzo[g,h,i]perylene
VIP	variable importance