Highlights CA/CPB nanofibers have a filtration efficiency of 99.9 % for aerosol (7−300 nm). The Ergun’s porosity of the nanofibers is 98 % and the permeability about 10 −11 m 2 . CA/CPB nanofibers are biodegradable and sustainable novel air filters. The nanofibers are able to retention environmental PM 2.5 , BC and also virus.

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Most of the world’s population lives in rural areas or small to medium-sized cities (totalling 68% of the world population), all of which are impacted by distant air pollution sources. In Brazil, primary pollutant emissions have decreased in urban centres because of government actions, while secondary pollutants such as surface ozone (O3) increased. In addition, O3 and its precursors can be worsening air quality in areas already affected by biofuels production, especially ethanol. We provide almost 3 months of hourly data (June 7, 2019 to August 25, 2019) for concentrations of O3, CO2 and other priority pollutants from a mobile station positioned to distinguish among pollutant plumes (biomass burning, metropolitan area of São Paulo (MASP) and other cities). Although the concentrations of O3 and CO2 were highest in the plumes from biomass burning, the MASP accounted for up to 80% of the O3 concentration in communities over 200 km away.

The aim of this study was to characterize the inorganic chemical composition of fine inhalable atmospheric particulate matter (PM 2.5 ) in medium-sized cities in Brazil. These cities account for a significant proportion of the population and are growing at rates above the national average, thereby demonstrating the importance of carefully analysing the possible impact of such growth on air quality over the coming decades. In 2013 and 2014, this study collected PM 2.5 samples from sites in the cities of Londrina and Maringa in two seasons: winter and summer. The mean concentration of PM 2.5 ranged from 4.4 µg m -3 and 3.7 µg m -3 during the summer to 10.3 µg m -3 and 8.0 µg m -3 in winter in Londrina and Maringa, respectively. The analysis of the major water-soluble ions, nitrate, sulphate and chloride, showed that they accounted for between 16.5% and 35.1% from the mass of PM 2.5 , with sulphate providing the greatest contribution in all the campaigns. The nitrate/sulphate ratios ranged from 0.2 and 0.6, which are similar to the figures cited in the literature for other regions of the world. Although the PM 2.5 concentrations are much lower than those observed in Asia and in Sao Paulo the participation of ions (%) is very close to that observed in Asian cities and significantly higher than the values recorded in other areas of Brazil, possibly as a result of the increased influence of burning of biomass and waste. The metals Zn, Pb, Cu and Mn found in the samples from all campaigns indicate that, in general, mobile sources are the main contributor to PM 2.5 . The winter campaigns showed the highest concentrations of black carbon equivalent (BCe). Absolute principal component analysis and enrichment factor analysis indicate the contribution of vehicular emission sources and biomass and waste burning to the inorganic chemical composition of PM 2.5 .