Mobile and Fixed-Site Measurements to Identify Spatial Distributions of Traffic-Related Pollution Sources in Los Angeles

Mei W. Tessum, Timothy Larson, Timothy R. Gould, Christopher D. Simpson, Michael G. Yost, Sverre Vedal

Research output: Contribution to journalArticlepeer-review

Abstract

Mobile monitoring and fixed-site monitoring using passive sampling devices (PSD) are popular air pollutant measurement techniques with complementary strengths and weaknesses. This study investigates the utility of combining data from concurrent 2-week mobile monitoring and fixed-site PSD campaigns in Los Angeles in the summer and early spring to identify sources of traffic-related air pollutants (TRAP) and their spatial distributions. There were strong to moderate correlations between mobile and fixed-site PSD measurements of both NO2 and NOx in the summer and spring (Pearson's r between 0.43 and 0.79), suggesting that the two data sets can be reliably combined for source apportionment. PCA identified the major TRAP sources as light-duty vehicle emissions, diesel exhaust, crankcase vent emissions, and an independent source of combustion-derived ultrafine particle emissions. The component scores of those four sources at each site were significantly correlated across the two seasons (Pearson's r between 0.58 and 0.79). Spatial maps of absolute principal component scores showed all sources to be most prominent near major roadways and the central business district and the ultrafine particle source being, in addition, more prominent near the airport. Mobile monitoring combined with fixed-site PSD sampling can provide high spatial resolution estimates of TRAP and can reveal underlying sources of exposure variability.

Original languageEnglish (US)
Pages (from-to)2844-2853
Number of pages10
JournalEnvironmental Science and Technology
Volume52
Issue number5
DOIs
StatePublished - Mar 6 2018

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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