Source Apportionment of Particulate Matter in the Metropolitan Area of Querétaro (Central Mexico): First Case Study

Abstract

Exposure to particulate matter (PM) represents an important health risk in urban areas because it is associated with cardiovascular and respiratory diseases. Knowledge of PM composition and sources is essential in the design of policies to reduce the burden of airborne particles. Although several urban areas in Mexico struggle with maintaining good air quality, little is known about the processes that determine the presence of pollutants in the atmosphere beyond Mexico City. Here, we describe the chemical composition of PM10 and PM2.5 in the metropolitan area of Querétaro (in Central Mexico) and identify the major emission sources and contributions using positive matrix factorization. We used, combined, and compared different data sets to gain more insight into the sources found. Three sources were found for PM10: resuspension of mineral and construction dust, an anthropogenic source with incineration, industrial, and secondary particles, and biomass burning. For PM2.5, the sources found include resuspension, anthropogenic (with incineration and industrial particles), vehicular, biomass burning, and secondary. This study is the first to investigate the chemical composition and source apportionment of PM10 and PM2.5 in the metropolitan area of Querétaro. Although some of the sources found are probably local, the regional contribution to the PM concentration is significant, thus revealing the importance of studying the central region of Mexico, which is an important industrial and agricultural area, with 20 million people distributed in several major urban areas, in an integrated way.