According to the positive matrix factorization (PMF) receptor model, primary sources for every four-year period were identified as oil burning, biomass burning, and vehicular emissions from gasoline and diesel-powered engines.
According to the source apportionment by diagnostic ratios and PMF model, coal combustion and traffic emission were estimated to be the main sources of PAHs in Dalian, followed by petroleum release and biomass burning.
The m/z signatures of known source marker compounds (levoglucosan and resin acids, polycyclic aromatic hydrocarbons, nicotine) in the mass spectra were used to assign PMF factors to biomass burning, traffic, and smoking emission sources.