The association between exposure to air pollutants and respiratory diseases is well known. This study aimed to identify the association between this exposure and hospitalizations for COVID-19 in São José dos Campos, SP, a medium-sized city, between April 2020 and April 2021. Hospitalization data, concerning code B34.2, was supplied by DATASUS, and data concerning pollutants and climate variables were supplied by CETESB. Cases were quantified by sex, age, length of hospital stay in days, and type of discharge, whether hospital discharge or death. The negative binomial regression model was chosen. Estimates were produced for the relative risk (RR) of significant exposure to pollutants (P≤0.05) with a 10 µg/m3 increase of pollutant, as well as for excess hospitalizations. There were 1873 hospitalizations, with a daily average of 4.7 (±3.8), ranging from zero to 21: 716 deaths (38.2%) were recorded, 1065 admissions were men, and women were less susceptible (OR=0.82). The average age of women was higher than that of men; in cases of death, men were older than women; discharged patients were younger. All the above variables were significant. The risk of ozone exposure was higher and more significant in Lag 2, and the risk of nitrogen dioxide exposure was high in Lag 3, which was the period of the highest increase in hospitalizations, at 11.3%. The findings of this study, the first conducted in Brazil, corroborate the results of studies conducted in other centers.

O dióxido de titânio tem sido bastante investigado para a remoção de poluentes orgânicos. É um material polimórfico, o qual dependendo das condições e tipo de método de síntese empregado na sua preparação pode ser monofásico ou bifásico, com predominância de uma das fases. Sendo assim, este trabalho propõe a avaliação da estrutura, morfologia e atividade fotocatalítica na degradação do corante vermelho de metila por amostras de TiO2 sintetizado pelo método Pechini com relação de ácido cítrico/cátion metálico de 4:1 e 6:1. As amostras sintetizadas foram calcinadasa 500ºC por 1hora e foram caracterizadas pela técnica de difração de raios X em amostras policristalinas com o uso do método de refinamento Rietveld, análise textural, microscopia eletrônica de varredura e fotocataliticamente em testes de bancada, usando o corante vermelho de metila. Os resultados obtidos mostraram que a amostra 4:1 levou à formação das duas fases, com 89% dafase anatásio e 11% da fase rutilo, enquanto a amostra 6:1 levou apenas à formação da fase anatásio. A amostra 4:1, que apresentou a mistura da fase anatásio e rutilo demonstrou ser mais eficiente fotocataliticamente do que a amostra 6:1.

Titanium dioxide has been widely investigated in the removal of organic pollutants. It is a polymorphic material which, depending on the conditions and the type of synthetic method used in its preparation may be monophasic or biphasic, with predominance of one of the phases. Therefore, this paper proposes the evaluation of the structure, morphology and photocatalytic activity in the degradation of methyl red dye byTiO2 samples synthesized by the Pechini method with citric acid/metal cation ratios of 4:1 and 6:1. The synthesized samples were calcined at 500°C for 1 hour and were characterized by X-ray powder diffraction technique by using Rietveld refinement, textural analysis, scanning electron microscopy and photocatalytic test sin bench scale, using methyl red dye. The results showed that the sample 4:1 led to the formation of two phases, 89% anatase and 11% rutile, while the sample 6:1 led only to the formation of the anatase phase. The 4:1 sample, a mixture of anatase and rutile phase, photocatalytically, was more effective than the 6:1 sample.