An integrated assessment of the impacts of PM2.5 and black carbon particles on the air quality of a large Brazilian city

Abstract

Data on airborne fine particle (PM_2.5) emissions and concentrations in cities are valuable for traffic and air quality managers, urban planners, health practitioners, researchers, and ultimately for legislators and decision makers. Emissions and ambient concentrations of PM_2.5 and black carbon (BC) were assessed in the city of Curitiba, southern Brazil. The methodology combined a month-long monitoring campaign with both fixed and mobile instruments, development of emission inventories, and dispersion model simulations on different scales. The mean urban background PM_2.5 concentrations during the campaign were 7.3 μg m⁻³ in Curitiba city center, but three- to fourfold higher (25.3 μg m^-3) in a residential area on the city’s outskirts, indicating the presence of local sources, possibly linked to biomass combustion. BC concentrations seemed to be more uniformly distributed over the city, with mean urban background concentrations around 2 μg m⁻³, half of which due to local traffic emissions. Higher mean BC concentrations (3–5 μg m^-3) were found along busy roads. The dispersion modeling also showed high PM_2.5 and BC concentrations along the heavily transited ring road. However, the lack of in situ data over these peripheral areas prevented the verification of the model output. The vehicular emission factors for PM_2.5 and BC from the literature were found not to be suitable for Curitiba’s fleet and needed to be adjusted. The integrated approach of this study can be implemented in other cities, as long as an open data policy and a close cooperation among regional, municipal authorities and academia can be achieved.