Source apportionment resolved by time of day for improved deconvolution of primary source contributions to air pollution

Abstract. Present methodologies for source apportionment assume fixed profiles. Since meteorology and human activity patterns change seasonally diurnally, application of techniques to shorter rather than longer time periods generates more representative mass spectra. Here, we present a new method conduct resolved by day using the underlying approach positive matrix factorization (PMF). We call this “time-of-day PMF” statistically demonstrate improvements in over traditional PMF. report on conducted four example two seasons (winter monsoon 2017), organic aerosol measurements from an chemical speciation monitor (ACSM). deploy EPA PMF tool with Multilinear Engine (ME-2) as solver. Compared seasonal approach, extract larger number factors well that represent expected sources primary time-of-day By capturing diurnal series at low computational cost, can utilize large datasets collected long-term monitoring improve characterization compared approaches do not resolve day.