Sources Affecting PM&amp;lt;sub&amp;gt;2.5&amp;lt;/sub&amp;gt; Concentrations at a Rural Semi-Arid Coastal Site in South Texas

Saritha Karnae,Kuruvilla John

doi:10.4236/jep.2013.41018

Abstract

Principal component analysis/absolute principal component scores (PCA/APCS) and positive matrix factorization (PMF2), an advanced factor analysis technique were employed to apportion the sources influencing the PM2.5 levels measured during 2003 through 2005 at a rural coastal site located within the Corpus Christi urban airshed in South Texas. PCA/APCS identified five sources while PMF2 apportioned an optimal solution of eight sources. Both PCA/APCS and PMF2 quantified secondary sulfates to be the major contributor accounting for 47% and 45% of the apportioned PM2.5 levels. The other common sources apportioned by the models included crustal dust, fresh sea salt and traffic emissions. PMF2 successfully apportioned distinct sources of fresh and aged sea salt along with biomass burns while PCA/APCS was unsuccessful in identifying aged sea salt and biomass burns; however it successfully identified secondary organic aerosols from photochemical oxidations and also emitted by petrochemical refineries. The influence of long range transport was noted for sources such as secondary sulfates, biomass burns and crustal dust affecting the region. Continued collection of speciation data at the rural and urban sites will enhance the understanding of local versus regional source contributions for air quality policy makers and stakeholders.

Highlights

Epidemiological studies conducted over the past decade have provided ample confirmation of the adverse effects of PM2.5 on human health and welfare, and reiterating the need for source identification and quantification
Principal component analysis/absolute principal component scores (PCA/APCS) and positive matrix factorization (PMF2), an advanced factor analysis technique were employed to apportion the sources influencing the PM2.5 levels measured during 2003 through 2005 at a rural coastal site located within the Corpus Christi urban airshed in South Texas
PCA/APCS apportioned five sources explaining 84% of variance in the PM2.5 concentrations measured at the rural coastal monitoring site (CAMS 314) adjacent to the Corpus Christi urban airshed

Summary

Introduction

Epidemiological studies conducted over the past decade have provided ample confirmation of the adverse effects of PM2.5 on human health and welfare, and reiterating the need for source identification and quantification. Paatero (1997) has developed an advanced multivariate factor analysis model Positive Matrix Factorization 2 (PMF) based on least squares approach which incorporates an optimization process to improve the source apportionment using uncertainty or error estimates involved in sample collection and analysis [10]. This technique has been employed by various researchers to apportion sources contributing to the ambient levels of fine and coarse particulate matter as well as ozone precursors including volatile organic compounds (VOC) [11,12,13,14,15,16,17,18]

Results

Discussion

Conclusion