RESUMO A transmissão de infecções respiratórias tem importante impacto na saúde humana, sobretudo no atual contexto da pandemia de COVID-19. Neste trabalho, discute-se um purificador de ar que utiliza radiação ultravioleta-C (UVC) e filtro high efficiency particulate air (HEPA) como mecanismos para descontaminar ambientes internos com baixa circulação de ar. Para avaliar os parâmetros físico-químicos do equipamento e sua ação microbicida, foram determinados a irradiância produzida pela lâmpada, a vazão na entrada e saída do dispositivo, as alterações na concentração de ozônio e o potencial de descontaminação do equipamento para Staphylococcus aureus, Escherichia coli e Candida albicans. A dose total de radiação UVC que o ar recebe ao passar pelo equipamento foi de 801,4 μJ cm-2, o que representaria a inativação de até 80% de Sars-CoV-2 no ar. Além disso, a eficiência de filtração foi reduzida para cerca de 60% com a diminuição do tamanho da partícula para partículas com menos de 1 μm e manteve-se acima de 90% para MP2,5 e MP10. Nos testes microbiológicos, observou-se redução de 99,4, 99,9 e 99,5% para S. aureus, E. coli e C. albicans, respectivamente, em 11 minutos.

ABSTRACT The transmission of respiratory infections has an important role on human health, especially in the current context of the COVID-19 pandemic. In this work, we present the assessment of an air purifier that uses ultraviolet-C (UVC) radiation and a “High Efficiency Particulate Air” (HEPA) filter as mechanisms to decontaminate indoor environments with low air circulation. To assess the physicochemical and microbicidal characteristics of the equipment, the irradiance produced by the lamp, the flow rate at the entrance and exit of the device, possible changes in the ozone concentration and the equipment's decontamination potential for Staphylococcus aureus, Escherichia coli and Candida albicans. The total dose of UVC radiation that the air receives when passing through the equipment was 801.4 μJ cm-2, which would represent an inactivation of up to 80% of SARS-CoV-2 in the air. Furthermore, the filtration efficiency dropped with smaller particle diameter, and reduced to around 60% for particles with less than 1 μm and remained above 90% for PM2.5 and PM10. In microbiological tests, there was a reduction of 99.4%, 99.9% and 99.5% for S aureus, E. coli and C. albicans, respectively, in 11 minutes.

O presente trabalho apresenta o estudo sobre 16 HPAs prioritários em material particulado atmosférico de três sítios próximos a Salvador-BA: (i) Estação da Lapa, estação de ônibus da Região Metropolitana de Salvador; (ii) Porto de Aratu, impactado por intenso movimento de matérias-primas e (iii) Bananeira, localizado na Ilha de Maré, vilarejo que tem como principais atividades a pesca e artesanato. Resultados mostraram que o BbF (0,130-6,85 ng m-3) foi o HPA com as concentrações mais elevadas em Aratu e Bananeira e CRY (0,075-6,85 ng m-3) apresentou nível mais elevado na Lapa. As fontes de HPAs nos sítios estudados foram principalmente de origem antrópica, tais como veículos de pequeno e grande portes, carregamentos do porto, ressuspensão de partículas do solo, queima de diesel das embarcações e a queima de carvão e madeira para produção de energia.

The present work has aimed to determine the 16 US EPA priority PAH atmospheric particulate matter levels present in three sites around Salvador, Bahia: (i) Lapa bus station, strongly impacted by heavy-duty diesel vehicles; (ii) Aratu harbor, impacted by an intense movement of goods, and (iii) Bananeira village on Maré Island, a non vehicle-influenced site with activities such as handcraft work and fisheries. Results indicated that BbF (0.130-6.85 ng m-3) is the PAH with highest concentration in samples from Aratu harbor and Bananeira and CRY (0.075-6.85 ng m-3) presented higher concentrations at Lapa station. PAH sources from studied sites were mainly of anthropogenic origin such as gasoline-fueled light-duty vehicles and diesel-fueled heavy-duty vehicles, discharges in the port, diesel burning from ships, dust ressuspension, indoor soot from cooking, and coal and wood combustion for energy production.

In order to characterize the composition of the main urban air organic compounds in the megacity of Sao Paulo, analysis of samples collected during the winter of 2003 downtown was carried out. The samplings were performed on the roof of a building in the commercial center of São Paulo. Hydrocarbons and carbonyls compounds were collected on August 4, 5 and 6. Comparing to previous data, the concentration of hydrocarbons presented no decrease in the concentration, except for the aldehydes, which decreased when compared to previous data. Among the HCs species analyzed, the highest concentrations observed were those of toluene (7.5 ± 3.4 ppbv), n-decane (3.2 ± 2.0 ppbv), benzene (2.7 ± 1.4 ppbv) and 1,3,5-trimethylbenzene (2.2 ± 1.5 ppbv).

In this study atmospheric particulates of PAHs were measured in Araraquara, Piracicaba and São Paulo in July 2003 (sugarcane harvest season in Araraquara and Piracicaba) and in Araraquara in March of 2003. The results were normalized to the total PAH concentrations. Comparison among the sites and principal component analysis (PCA) were used to investigate possible tracers of emission. Fluoranthene and pyrene concentrations were higher in Piracicaba and Araraquara samples. These PAH were also responsible for the largest negative loadings on the second principal component and account for the negative scores and for the formation of the Araraquara and Piracicaba group.

It was identified and quantified several organic compounds in the atmosphere of a site into Amazon Basin with high impact of biomass burning emission. It was important to know the particulate matter composition with respect to n-alkanes and PAH associated with the particulate matter because they provided indication on the main sources contributing to airborne particles, the contribution of natural vs. man-made emission and the aging of the particles. The main classes of compounds observed were n-alkanes, PAH and nitro-PAH. It was observed the formation of nitro-PAH from photochemical reactions. The aerosol mass concentration is mainly associated with fluoranthene, pyrene and benzo(ghi)perylene. Environmental and direct emissions samples (flaming and smoldering) were collected and analysed.