Source Identification and Apportionment of Atmospheric Aerosol over Port Arthur of Texas

Ambient air samples of PM 2.5 were collected at a monitoring site in Port Arthur of Texas by US EPA (Environ- mental Protection Agency) from September of 2005 to June of 2009. A total of 343 samples with 53 species were measured and the data were analyzed by positive matrix factorization (PMF) to infer the sources of PM observed at the site. The analysis identified eleven source-related factors: sulfate-rich secondary aerosol (31.9%), motor vehicle (22.3%), aged sea-salt (11.1%), cement/carbon-rich (8.3%), airborne soil (7.4%), railroad traffic (5.7%), metal processing (3.1%), sea salt (3.0%), marine aerosol (2.8%), wood smoke (2.4%), and nitrate-rich secondary aerosol (1.9%). Basically, the factors of sulfate, airborne soil, and nitrate were likely to be regionally related sources. Motor vehicle, cement/carbon-rich, railroad traffic, metal processing, marine aerosol, and wood smoke factors were likely to be the local sources.