id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-287751-52e0tlcu	Dai, Qili	Changes in source contributions to particle number concentrations after the COVID-19 outbreak: Insights from a dispersion normalized PMF	2020-11-06		.txt	text/plain	4445	232	52	To reduce the influence of dilution on quantitative source estimates, a methodology for improving the accuracy of source apportionment results by incorporating a measure of dispersion, the ventilation coefficient, into the PMF analysis (called dispersion normalized PMF, DN-PMF) was applied to a PNC dataset measured from a field campaign that includes the Spring Festival event and the start of the COVID-19 lockdown in Tianjin, China. In addition to measured PNC data, auxiliary variables include gaseous pollutants (SO 2 , NO 2 , CO and O 3 ), PM 1 , PM 1-2.5 (PM 2.5 -PM 1 ), radiation and selected potential source tracer species (OC, EC, NO 3 -analyses to support factor interpretation. The best solution with the optimal number of factors was evaluated with selection criteria of appropriately narrow distributions of scaled residuals of PNCs and the physical interpretability of factors in terms of (a) examination of size factor profiles and its association with external variables, (b) source directionality from CBPF plots, and (c) diel patterns.	./cache/cord-287751-52e0tlcu.txt	./txt/cord-287751-52e0tlcu.txt