Source apportionment of ambient particle number concentrations in central Los Angeles using positive matrix factorization (PMF)

摘要: Abstract. In this study, the positive matrix factorization (PMF) receptor model (version 5.0) was used to identify and quantify major sources contributing particulate matter (PM) number concentrations, using PM size distributions in range of 13 nm 10 µm combined with several auxiliary variables, including black carbon (BC), elemental organic (EC/OC), mass gaseous pollutants, meteorological, traffic counts data, collected for about 9 months between August 2014 2015 central Los Angeles, CA. Several parameters, particle volume distribution profiles, profiles contributions different factors seasons total diurnal variations each resolved cold warm phases, weekday/weekend analysis factors, correlation variables relative contribution were sources. A six-factor solution identified as optimum aforementioned input data. The comprised nucleation, traffic 1, 2 (with a larger mode diameter than 1 factor), urban background aerosol, secondary soil/road dust. Traffic (1 2) contributor collectively making up above 60 % (60.8–68.4 %) concentrations during study period. Their also significantly higher phase compared phase. Nucleation another factor (an overall 17 %, ranging from 11.7 24 %), other dust, approximately 12 % (7.4–17.1), 2.1 % (1.5–2.5 %), 1.1 % (0.2–6.3 %), respectively, accounting 15 % (15.2–19.8 %) concentrations. As expected, dominated by smaller diameters, such nucleation. On hand, area mostly affected aerosols Results present can be parameters future epidemiological studies link adverse health effects well policymakers set targeted more protective emission standards PM.