Elemental composition of atmospheric PM10 and PM2.5 for a savanna (Cerrado) region of southern Amazonia

Ecosystems such as the Amazonian tropical forest and savanna (known locally as Cerrado) are undergoing sweeping changes, such as deforestation and burning to expand new areas of agriculture and farming. These activities generate an increase in the concentration of gases and particles emitted into the atmosphere, which can affect energy balance and biogeochemical cycles. To determine how human activities affected the emission of coarse and fine particulate matter (PM10 and PM2.5, respectively), atmospheric aerosol samples were collected continuously from June 2004 until April 2005 in the Cuiaba Basin of south-central Mato Grosso, Brazil, which contains a mixture of urban, agricultural, and native Cerrado land surface types. Aerosols were sampled using stacked filter units (SFU), which separate fine (d<2.5 μm) and coarse mode (2.5 μm2.5 and PM10, representing ca. 98% of all elements measured in the dry season and 94% in the wet season. The high enrichment factors observed in PM2.5 and PM10 suggest that anthropogenic activities were the dominant source for elements such as Cu, Zn and Pb. Factorial analysis allowed the identification of four main sources contributing to PM10 and PM2.5 composition, including biomass burning, soil dust, urban emissions and natural biogenic emissions. These data indicate that most of the aerosols measured in the Cuiaba Basin originate from land conversion and biomass burning, and to a lesser extent, urban activities. These patterns are similar to those observed from other Cerrado and Amazonian forest areas that are undergoing rapid and spatially extensive land-cover change.