Abstract
Abstract. São Paulo in Brazil has relatively relaxed regulations for ambient air pollution standards and often experiences high air pollution levels due to emissions of particulate pollutants from local sources and long-range transport of air masses impacted by biomass burning. In order to evaluate the sources of particulate air pollution and related health risks, a year-round sampling was done at the University of São Paulo campus (20 m a.g.l.), a green area near an important expressway. The sampling was performed for PM2. 5 ( ≤ 2. 5 µm) and PM10 ( ≤ 10 µm) in 2014 through intensive (everyday sampling in wintertime) and extensive campaigns (once a week for the whole year) with 24 h of sampling. This year was characterized by having lower average precipitation compared to meteorological data, and high-pollution episodes were observed all year round, with a significant increase in pollution level in the intensive campaign, which was performed during wintertime. Different chemical constituents, such as carbonaceous species, polycyclic aromatic hydrocarbons (PAHs) and derivatives, water-soluble ions, and biomass burning tracers were identified in order to evaluate health risks and to apportion sources. The species such as PAHs, inorganic and organic ions, and monosaccharides were determined using chromatographic techniques and carbonaceous species using thermal-optical analysis. Trace elements were determined using inductively coupled plasma mass spectrometry. The risks associated with particulate matter exposure based on PAH concentrations were also assessed, along with indexes such as the benzo[a]pyrene equivalent (BaPE) and lung cancer risk (LCR). High BaPE and LCR were observed in most of the samples, rising to critical values in the wintertime. Also, biomass burning tracers and PAHs were higher in this season, while secondarily formed ions presented low variation throughout the year. Meanwhile, vehicular tracer species were also higher in the intensive campaign, suggesting the influence of lower dispersion conditions in that period. Source apportionment was performed using positive matrix factorization (PMF), which indicated five different factors: road dust, industrial emissions, vehicular exhaust, biomass burning and secondary processes. The results highlighted the contribution of vehicular emissions and the significant input from biomass combustion in wintertime, suggesting that most of the particulate matter is due to local sources, in addition to the influence of pre-harvest sugarcane burning.
Highlights
Air pollution caused by atmospheric particulate matter (PM) is one of the major environmental problems encountered in Latin American cities such as São Paulo (Brazil), Mexico City (Mexico), Bogotá (Colombia) and Santiago (Chile) (Romero-Lankao et al, 2013; Vasconcellos et al, 2010, 2011a; Villalobos et al, 2015)
The risks of polycyclic aromatic hydrocarbons (PAHs) for human health were assessed with levels exceeding the suggested guidelines
positive matrix factorization (PMF) analysis was performed and source profiles were obtained for Int2.5, Ext2.5 and Ext10
Summary
Air pollution caused by atmospheric particulate matter (PM) is one of the major environmental problems encountered in Latin American cities such as São Paulo (Brazil), Mexico City (Mexico), Bogotá (Colombia) and Santiago (Chile) (Romero-Lankao et al, 2013; Vasconcellos et al, 2010, 2011a; Villalobos et al, 2015). Several studies have highlighted a statistical relation between PM and health problems, including respiratory and cardiovascular diseases and genotoxic risks (Newby et al, 2015; de Oliveira Alves et al, 2014; Pope, 2000). In this context, PM2.5 (PM with an aerodynamic diameter smaller than 2.5 μm) and PM10 (PM with an aerodynamic diameter smaller than 10 μm) are particles that are able to penetrate the respiratory system, with PM2.5 reaching alveoli in the lungs, and induce adverse impacts on human health (Cai et al, 2015; Kumar et al, 2014). PM plays an important role in ecosystem biogeochemistry, the hydrological cycle, cloud formation and atmospheric circulation (Pöschl, 2005)
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