Volume 13, No. 1, February 2013, Pages 60-71 PDF(1020 KB)
Identification of PM2.5 Sources Affecting a Semi-Arid Coastal Region Using a Chemical Mass Balance Model
Priya Subramoney1, Saritha Karnae2, Zuber Farooqui3, Kuruvilla John3, Ashok K. Gupta4
1 FQLabs, 3375 Koapaka St., Suite G314, Honolulu, HI 96819, USA
2 Department of Environmental Engineering, Texas A&M University-Kingsville, 700 University Blvd, MSC 213, Kingsville, Texas 78363, USA
3 Department of Mechanical and Energy Engineering, College of Engineering, University of North Texas, 3940 N. Elm, Denton, Texas 76207, USA
4 Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
Chemical mass balance (CMB 8.2), a source apportionment model, was employed to identify the sources influencing the measured PM2.5 levels at an industrialized urban and a coastal rural site located in Corpus Christi, Texas. A speciated PM2.5 dataset consisting of 110 common sampling days with 25 key species, including elements, water soluble ions, organic and elemental carbon measured from 2003 to 2005, was used in this analysis. Based on the local and regional emissions characteristics, thirteen generic source profiles were selected from US EPA’s SPECIATE library for the CMB model application. Secondary sulfate was the major contributor at both sites with average concentrations of 3.45 μg/m3 (42% of the apportioned mass) and 3.06 μg/m3 (37%), respectively. Secondary organic aerosols were observed to be higher at the urban site (1.62 μg/m3) than at the rural one (1.07 μg/m3). Due to its location being closer to the Gulf of Mexico, the influence of marine aerosols was higher at the coastal rural site (1.15 μg/m3) than at the urban one (0.37 μg/m3). Unique sources, including the petroleum industry and industrial manufacturing, were found to influence the measured PM2.5 levels at the industrialized urban site, with average apportioned concentrations of 0.17 μg/m3 and 0.02 μg/m3, respectively. The annual average PM2.5 concentrations showed a gradual increase in the secondary components, including sulfates and organic aerosols at both sites during the study period.
Chemical mass balance (CMB); Coastal urban region; PM2.5; Source apportionment.