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.

PM2.5 Characterization and Source Apportionment Using Positive Matrix Factorization at San Luis Potosi City, Mexico, during the Years 2017–2018

“…Although San Luis Potosí is a growing city of just over 1.2 million inhabitants, the PM2.5 mass concentrations do not frequently exceed the official regulations for this pollutant [37]; the obtained PM2.5 composition for this northern area of the city of San Luis Potosi showed a strong chemical reactivity and a high toxic composition due to the presence of heavy metals (Pb, As, Zn, and Cu) which have been reported since decades [65], and linked to cancer and non-cancer health risk [2]. Heavy metals concentrations surpassing for other studies carried out in larger cities such as Mexico City [22,49], Monterrey [66], Queretaro [64], and Hidalgo [15]. Also, strong chemical reactivity is due to high concentrations of carbonaceous compounds, a high amount of S due to fuel combustion, and a high concentration of Ca due to the soil resuspension towards the city and the main fluorite industry in Mexico produced at Villa de Zaragoza (near 40 km from SLP City), which is widely used in the metal-mechanic, chemical and construction industries.…”

“…The seventh source corresponds to the Chemical Industry composed of OC, Cl, and EC with high industrial markers contribution as Mn, Cr, Fe, Ni, and Pb. This source is identified in Mexican industrial zones, in Mexico City in the north zone [22,46], and in Queretaro [64].…”

“…Queretaro [64], and Hidalgo [15]. Also, strong chemical reactivity is due to high concentrations of carbonaceous compounds, a high amount of S due to fuel combustion, and a high concentration of Ca due to the soil resuspension towards the city and the main fluorite industry in Mexico produced at Villa de Zaragoza (near 40 km from SLP City), which is widely used in the metal-mechanic, chemical and construction industries.…”

Mario Molina Memorial Special Issue

“…Molina was a champion of the study of air pollution in megacities and the translation of science into action for cleaner air. Papers in this virtual special issue include source apportionment for the metropolitan area of Querétaro (central Mexico) as well as modeling insights into sources and causal factors of pollution in India and Bangladesh . Ultra-high-performance liquid chromatography with tandem mass spectrometry revealed trends in organosulfate and nitrooxy organosulfate formation chemistry in Guangzhou, China .…”