PM speciation and sources in Mexico during the MILAGRO-2006 Campaign X. Querol1, J. Pey1, M. C. Minguillón1, N. Pérez1, A. Alastuey1, M. Viana1, T. Moreno1, R. M. Bernabé2, S. Blanco2, B. Cárdenas2, E. Vega3, G. Sosa3, S. Escalona3, H. Ruiz3, and B. Artíñano4 1Instituto de Ciencias de la Tierra "Jaume Almera", CSIC. C/ Lluís Solé i Sabarís s/n, 08028 Barcelona, Spain 2Centro Nacional de Investigación y Capacitación Ambiental, CENICA. Periférico 5000, Col. Insurgentes Cuicuilco, C.P. 04530, Delegación Coyoacán, Mexico D.F., Mexico 3Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan. Delegación Gustavo A. Madero. 07730, Mexico, D.F, Mexico 4CIEMAT, Avda. Complutense 22, 28040 Madrid, Spain
Abstract. Levels of PM10, PM2.5 and PM1 and chemical speciation of
PM10 and PM2.5 were measured during the MILAGRO campaign (1st
to 31st March 2006, but extended in some cases until 6th April) at
four urban, one suburban, two rural background and two rural sites, with
different degree of industrial influence, in the Mexico City Metropolitan
Area (MCMA) and adjacent regions. PM10 and PM2.5 daily levels
varied between 50–56μg/m3 and 24–46μg/m3 at the urban
sites, 22–35μg/m3 and 13–25μg/m3 at the rural sites,
and 75μg/m3 and 31μg/m3 at the industrial hotspot, lower than those recorded at some Asian mega-cities and
similar to those recorded at other Latin American cities. At the urban
sites, hourly PM2.5 and PM1 concentrations showed a marked impact
of road traffic emissions (at rush hours), with levels of coarse PM
remaining elevated during daytime. At the suburban and rural sites
different PM daily patterns were registered according to the influence of
the pollution plume from MCMA, and also of local soil resuspension.
The speciation studies showed that mineral matter accounted for 25–27%
of bulk PM10 at the urban sites and a higher proportion (up to 43%)
at the suburban and rural sites. This pattern is repeated in PM2.5,
with 15% at urban and 28% at suburban and rural sites. Carbonaceous
compounds accounted for a significant proportion at the urban and industrial
sites (32–46% in PM10, and 51–55% in PM2.5), markedly
reduced at the suburban and rural sites (16–23% in PM10, and 30%
in PM2.5). The secondary inorganic aerosols accounted for 10–20% of
bulk PM10 at urban, suburban, rural and industrial sites, with a higher
proportion (40%) at the industrial background site. A relatively high
proportion of nitrate in rural sites was present in the coarse fraction.
Typically anthropogenic elements (As, Cr, Zn, Cu, Pb, Sn, Sb, Ba, among
others) showed considerably high levels at the urban sites; however levels
of particulate Hg and crustal trace elements (Rb, Ti, La, Sc, Ga) were
generally higher at the suburban site.
Principal component analysis identified three major common factors: crustal,
regional background and road traffic. Moreover, some specific factors were
obtained for each site.
Citation: Querol, X., Pey, J., Minguillón, M. C., Pérez, N., Alastuey, A., Viana, M., Moreno, T., Bernabé, R. M., Blanco, S., Cárdenas, B., Vega, E., Sosa, G., Escalona, S., Ruiz, H., and Artíñano, B.: PM speciation and sources in Mexico during the MILAGRO-2006 Campaign, Atmos. Chem. Phys., 8, 111-128, doi:10.5194/acp-8-111-2008, 2008.