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.