Heavy Metal Content in PM2.5Air Samples Collected in the Metropolitan Area of Monterrey, México

The air PM2.5 concentration and its heavy metal content (Fe, Pb, Mn, Ni, As) were measured in the Metropolitan Area of Monterrey, Mexicoin Mexico, an area that is characterized by both very active and diverse industrial activity and intense highway traffic and industrial activity. The 24-h PM2.5 samples were collected in two different zones during a 1-year-long measurement program (February 2008–February 2009). The year PM2.5 average was above 15 μg/m3 exceeding Mexican and international standards. The difference of PM2.5 in each zone was not statistically significant. The greatest metal content was for iron, followed by lead, manganese, nickel and arsenic. The difference in metal content for Pb, Mn, and As was statistically significant.