This study evaluated the pollutant levels (NO2, SO2, CO, and O3), air quality index (AQI) and the influence of meteorological variables and coronavirus disease (COVID-19) pandemic on the air quality in Rio de Janeiro. The data set used comprises periods before (March-April, 2019) and during pandemic (March-April, 2020). According to the AQI results, on most days, the air quality was ranked as “good”. Brazilian air quality standards for SO2, O3, and NO2 were not exceeded in any of the monitoring stations during partial lockdown, while CO exceeded in all periods in one site due to industrial emission. Comparing both periods, descriptive statistics for the meteorological parameters presented no differences, which suggests similar conditions. However, when evaluated week by week in 2020, weather conditions presented some differences that probably affected pollutant concentrations. The correlations between O3 and NO2 and some meteorological parameters indicate that variations in both favored ozone formation, since it is a photochemical process favored by temperature and solar radiation and that, in Rio de Janeiro, low NO2 concentrations lead to increased O3. The improvements on air quality during the partial lockdown may be attributed mainly to a reduction on emission sources rather than weather conditions.

This study evaluated the concentration profiles of regulated and unregulated pollutants emitted from a stationary diesel engine cycle, operating at the speed of 1800 rpm and 0% load, using biofuels and binary blends. The experimental test considered fuel burning time on three different periods and storage times. The operation of the engine when it is still cold, for example at 15 minutes, showed negative effect on particulate matter (PM), benzene and ethylbenzene emissions in pure soybean biodiesel (B100) compared to the blend of diesel with 5% biodiesel (B5). Regarding to the concentration of mono aromatics, aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAH), this study showed similar results to those reported in the literature, where B5 fuel emits more pollutants than pure biodiesel. However, comparing some pollutants individually, benzene and ethylbenzene emissions were higher for B100 and pure soybean biodiesel with butil-hydroxyanisol additive (B100 Adt). The B5 showed the highest concentration profile for the PAH sum in the gaseous and particulate phases in longer engine operation periods.

Material particulado atmosférico (PM) é um poluente composto por diversos metais, que quando acumulados no sistema respiratório, podem causar sérios problemas de saúde. Os métodos IO-3.1 (extração de metais em PM) e IO-3.4 [determinação de metais por espectrometria de emissão atômica por plasma acoplado indutivamente (ICP-OES)] são os recomendados pela Agência de Proteção Ambiental dos Estados Unidos. Com o objetivo de avaliar o desempenho do método desenvolvido em nosso laboratório para extração de metais em PM utilizando HNO3 p.a. bidestilado e determinação por ICP-OES de Al, Ca, Cd, Cu, Cr, Fe, K, Mg, Mn, Na, Ni, Pb, Ti, V e Zn, a validação foi executada de acordo com os critérios estabelecidos pelo INMETRO, determinando parâmetros: seletividade, linearidade, precisão, exatidão, robustez, limites de detecção e quantificação, assim como a comparação da eficiência e precisão com o método IO-3.1. Resultados mostraram que o nosso método atendeu todos critérios de validação estabelecidos pelo INMETRO. Além disso, mostrou-se ser equivalente ao método IO-3.1.

Atmospheric particulate matter (PM) is a pollutant composed by various metals, that when accumulated in the respiratory system may cause serious health problems. Methods IO-3.1 (metal extraction in PM) and IO-3.4 [metal determination by inductively coupled plasma optical emission spectrometry (ICP-OES)] are the recommended by the United State Environmental Protection Agency. With the intent to evaluate the performance of the method developed in our laboratory for the extraction of metal in PM with HNO3 p.a. bidistilled and determination by ICP-OES of Al, Ca, Cd, Cu, Cr, Fe, K, Mg, Mn, Na, Ni, Pb, Ti, V and Zn, validation was executed according to the criteria established by the INMETRO determining the parameters: selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification, as well as the comparison of the efficiency and precision with IO-3.1 method. The results show that our method meets all validation criteria established by the INMETRO; furthermore, it shows to be equivalent to IO-3.1 method.