O3	Ozone
FWP	Fenwei Plain
HYSPLIT	Single-particle Lagrangian integrated trajectory
PSCF	Potential source contribution function
WPSCF	Weighted potential source contribution function
CWT	Concentration weighted trajectory
WCWT	Weighted concentration weighted trajectory
VOCs	Volatile organic compounds
NOx	Nitrogen oxides
BTH	Beijing-Tianjin-Hebei
YRD	Yangtze River Delta
PRD	Pearl River Delta
NCP	North China Plain
XA	Xi’an
JZ	Jinzhong
LY	Luoyang
XY	Xianyang
APPCAP	Air pollution prevention and control action plan
CNEMC	China National Environmental Monitoring Centre
ECMWF	European Centre for Medium-Range Weather Forecasts
NCEP	National Centers for Environmental Prediction
GDAS	Global Data Assimilation System
NOAA	National Oceanic and Atmospheric Administration
PMF	Positive matrix factorization
PCA	Principal component analysis
CMB	Chemical mass balance
CNEMC	China National Environmental Monitoring Centre
MDA8 O3	Daily maximum 8 h average O3
PCT	T-model obliquely rotated principal component analysis
BVOCs	Biogenic volatile organic compounds
SOAs	Secondary organic aerosols
MDL	Method detection limit
EF	Error fraction
OVOCs	Oxygenated volatile organic compounds
OPS	O3-precursor sensitivity
HPF	High-pressure front
HPC	High-pressure control
LPF	Low-pressure front
HPB	High-pressure back
LTF	Low-pressure trough front
EPF	Equal-pressure field
LPG	Liquefied petroleum gas
MTBE	Methyl tert-butyl ether