Assessment of atmospheric particulate matter in São Carlos‐SP, Brazil

The monitoring of respirable particulate matter (PM₁₀) and of total carbon percentage (mass basis) in the atmosphere of São Carlos (SP) was performed in the period between September 1997 and January 2000. São Carlos, located in the central region of the state of São Paulo, has a population of close to 180,000 inhabitants and about 500 industrial establishments of medium to small size, mainly dealing with metallurgy, textiles, food and ceramics. The equipment used for air monitoring was a high volume sampler (GVS‐GRASEBY/GMW) equipped with a one‐stage inertial separator for a 10μm particle cut diameter. The PM₁₀ concentration was determined by gravimetry and the total carbon concentration by the Ströheim method. The results show a well defined seasonal dependence of both the PM₁₀ and of the total carbon concentration. Higher concentrations of PM₁₀ and carbon were observed in autumn and winter, which also coincided with low relative humidity and precipitation. The measured trends were compared with the PM₁₀ data from the city of São Paulo in the same period and showed similar seasonal dependence. However, in relative terms, the PM₁₀ concentration in São Carlos showed stronger seasonal dependence than in São Paulo.