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Background: There is a vast body of literature covering the association between air pollution exposure and nonaccidental mortality. However, the role of socioeconomic status (SES) in this relationship is still not fully understood. Objectives: We investigated if individual and contextual SES modified the relationship between short-term exposure to ozone (O3), nitrogen dioxide (NO2), and particulate matter with aerodynamic diameter <10 µm (PM10) on cardiovascular, respiratory, and all nonaccidental mortality. Methods: We conducted a time-stratified case-crossover study. Analyses were based on information on 280,685 deaths from 2011 to 2015 in the city of São Paulo. Education was used as an individual SES, and information on the district of residence was used to build a contextual SES. Exposure to PM10, NO2, and O3 was accessed from monitoring stations and linked to each case based on the date of death. Conditional logistic regression models were used to estimate the effects of air pollutants, and interaction terms were added to access the effect modification of SES. Results: Individuals with lower education had an increased chance of dying for all nonaccidental outcomes (1.54% [0.91%, 2.14%]) associated with exposure to PM10. Individuals living in lower SES areas had an increased chance of dying for nonaccidental (0.52% [0.16%, 0.88%]), cardiovascular (1.17% [0.88%, 1.46%]), and respiratory (1.70% [0.47%, 2.93%]) causes owing to NO2 exposure. Conclusion: Exposure to air pollutants increases the chance of dying by nonaccidental, cardiovascular, and respiratory causes. Lower educational levels and living on lower contextual SES increased the risk of mortality associated with air pollution exposure.

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Palladium phthalocyanine (PdPc) nanowires (NWs) were developed to achieve the gas sensing of NO2 in the sub-parts-per-million (ppm) range. Non-substituted metal phthalocyanine are well known for their p-type semiconducting behavior, which is responsible for its gas-sensing capabilities. Nanofabrication of the PdPc NWs was performed by physical vapor deposition (PVD) on an interdigitated gold electrode (IDE). The coordination of palladium in the structure was confirmed with UV-Vis spectroscopy. Gas-sensing experiments for NO2 detection were undertaken at different sensed gas concentrations from 4 ppm to 0.5 ppm at room temperature. In this work, the responses at different gas concentrations are reported. In addition, structural studies of the PdPc NWs with scanning electron microscopy (SEM) and electron-dispersive X-ray diffraction (EDS) are shown.

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Rapidly urbanizing cities in Latin America experience high levels of air pollution which are known risk factors for population health. However, the estimates of long-term exposure to air pollution are scarce in the region. We developed intraurban land use regression (LUR) models to map long-term exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) in the five largest cities in Colombia. We conducted air pollution measurement campaigns using gravimetric PM2.5 and passive NO2 sensors for 2 weeks during both the dry and rainy seasons in 2021 in the cities of Barranquilla, Bucaramanga, Bogotá, Cali, and Medellín, and combined these data with geospatial and meteorological variables. Annual models were developed using multivariable spatial regression models. The city annual PM2.5 mean concentrations measured ranged between 12.32 and 15.99 µg/m3 while NO2 concentrations ranged between 24.92 and 49.15 µg/m3. The PM2.5 annual models explained 82% of the variance (R2) in Medellín, 77% in Bucaramanga, 73% in Barranquilla, 70% in Cali, and 44% in Bogotá. The NO2 models explained 65% of the variance in Bucaramanga, 57% in Medellín, 44% in Cali, 40% in Bogotá, and 30% in Barranquilla. Most of the predictor variables included in the models were a combination of specific land use characteristics and roadway variables. Cross-validation suggests that PM2.5 outperformed NO2 models. The developed models can be used as exposure estimate in epidemiological studies, as input in hybrid models to improve personal exposure assessment, and for policy evaluation.

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The photochemical nitrating agent 5-methyl-1,4-dinitro-1H-imidazole (DNI) has been recently described as an effective tool for nitrating tyrosine residues in proteins under 390 nm irradiation (Long T. et al., 2021). Herein, we describe the one-step synthesis of DNI from the precursor 4-methyl-5-nitro-1H-imidazole with good yield (66%) and high purity (>99%). Spectral analysis of DNI reveals two maximum peaks (228 and 290 nm) with maximum nitration yields and kinetics occurring at 290 nm. Electron paramagnetic resonance (EPR)- and mass spectrometry (MS)- spin trapping analysis evidenced the formation of nitrogen dioxide (•NO2) upon irradiation of DNI, implying the homolysis of the N-N bond in the DNI molecule. Irradiation of DNI at 290, 390 nm, or UVA light (315-400 nm), produced tyrosine nitration, with yields approaching ca. 30% with respect to DNI at 290 nm exposure. Indeed, using alpha-synuclein as a model protein, the main protein post-translational modification triggered by DNI was the generation of 3-nitrotyrosine as shown by MS analysis. Additionally, the formation of di-tyrosine was also observed. Finally, intracellular •NO2 production upon DNI photolysis in bovine aortic endothelial cells was evidenced by the nitration of the tyrosine analog probe p-hydroxyphenylacetic acid (PHPA) and cellular protein tyrosine nitration.

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This study analyzes the effect of lockdown due to COVID-19 on the spatiotemporal variability of ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) concentrations in different provinces of continental Ecuador using satellite information from Sentinel - 5P. The statistical analysis includes data from 2018 to March 2021 and was performed based on three periods defined a priori: before, during, and after lockdown due to COVID-19, focusing on the provinces with the highest concentrations of the studied gases (hotspots). The results showed a significant decrease in NO2 concentrations during the COVID-19 lockdown period in all the study areas: the Metropolitan District of Quito (DMQ) and the provinces of Guayas and Santo Domingo de los Tsáchilas. In the period after lockdown, NO2 concentrations increased by over 20% when compared to the pre-lockdown period, which may be attributable to a shift towards private transportation due to health concerns. On the other hand, SO2 concentrations during the lockdown period showed irregular, non-significant variations; however, increases were observed in the provinces of Chimborazo, Guayas, Santa Elena, and Morona Santiago, which could be partly attributed to the eruptive activity of the Sangay volcano during 2019-2020. Conversely, O3 concentrations increased by 2-3% in the study areas; this anomalous behavior could be attributed to decreased levels of NOx, which react with ozone, reducing its concentration. Finally, satellite data validation using the corresponding data from monitoring stations in the DMQ showed correlation values of 0.9 for O3 data and 0.7 for NO2 data, while no significant correlation was found for SO2.

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BACKGROUND: Both air pollution and noise exposures have separately been shown to affect cognitive impairment. Here, we examine how air pollution and noise exposures interact to influence the development of incident dementia or cognitive impairment without dementia (CIND). METHODS: We used 1,612 Mexican American participants from the Sacramento Area Latino Study on Aging conducted from 1998 to 2007. Air pollution (nitrogen dioxides, particulate matter, ozone) and noise exposure levels were modeled with a land-use regression and via the SoundPLAN software package implemented with the Traffic Noise Model applied to the greater Sacramento area, respectively. Using Cox proportional hazard models, we estimated the hazard of incident dementia or CIND from air pollution exposure at the residence up to 5-years prior to diagnosis for the members of each risk set at event time. Further, we investigated whether noise exposure modified the association between air pollution exposure and dementia or CIND. RESULTS: In total, 104 incident dementia and 159 incident dementia/CIND cases were identified during the 10 years of follow-up. For each ∼2 µg/m3 increase in time-varying 1- and 5-year average PM2.5 exposure, the hazard of dementia increased 33% (HR = 1.33, 95%CI: 1.00, 1.76). The hazard ratios for NO2-related dementia/CIND and PM2.5-related dementia were stronger in high-noise (≥65 dB) exposed than low-noise (<65 dB) exposed participants. CONCLUSION: Our study indicates that PM2.5 and NO2 air pollution adversely affect cognition in elderly Mexican Americans. Our findings also suggest that air pollutants may interact with traffic-related noise exposure to affect cognitive function in vulnerable populations.

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The Covid-19 pandemic has negatively disrupted the way our economy and society functions. Nonetheless, there have also been some positive externalities of the pandemic on the environment. This paper aims to evaluate the concentration of nitrogen dioxide in Brazilian metropolitan regions after the policies adopted to confront Covid-19. In terms of methodological approach, the study employs cross-sectional quantitative analyses to compare the period of 36 days, i.e., 12 March to 16 April-before (in 2019) and after (in 2020) the pandemic declaration. The data were obtained from the Sentinel 5-P low-Earth polar satellite concerning Brazilian metropolitan regions (n = 24). Thorough spatial and statistical analyses were undertaken to identify the pre- and during pandemic nitrogen dioxide concentrations. Complementarily, Spearman's correlation test was performed with variables that impact air quality. The study results a fall in nitrogen dioxide concentration levels in 21 of the 24 metropolitan regions which was observed. The Spearman's correlation coefficient between the nitrogen dioxide variation and the vehicle density was 0.485, at a significance level of 0.05. With these findings in mind, the paper advocates that while the pandemic has a significant negative consequence on the health of population globally, a series of measures that result in a new social organization directly interfere in the reduction of air pollution that contributes to the quality of the air we breathe.

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ABSTRACT BACKGROUND: Exposure to air pollutants and illness by severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) infection can cause serious pulmonary impairment. OBJECTIVE: To identify a possible association between exposure to air pollutants and hospitalizations due to SARS-Cov-2. DESIGN AND SETTING: Ecological time-series study carried out in Taubaté, Tremembé, and Pindamonhangaba in 2020 and 2021. METHODS: Study with Sars-Cov-2 hospitalizations with information on hospitalization date, sex and age of the subjects, duration of hospitalization, type of discharge, and costs of these hospitalizations. Statistical analysis was performed through a negative binomial regression, with data on pollutant concentrations, temperature, air relative humidity, and hospitalization date. Coefficients obtained by the analysis were transformed into relative risk for hospitalization, which estimated hospitalizations excess according to an increase in pollutant concentrations. RESULTS: There were 1,300 hospitalizations and 368 deaths, with a predominance of men (61.7%). These data represent an incidence rate of 250.4 per 100,000 inhabitants and 28.4% hospital lethality. Significant exposure (P value < 0.05) occurred seven days before hospital admission (lag 7) for nitrogen dioxide (NO2) (relative risk, RR = 1.0124) and two days before hospital admission for PM2.5 (RR = 1.0216). A 10 μg/m3 in NO2 concentration would decrease by 320 hospitalizations and ¼ US $ 240,000 in costs; a 5 μg/m3 in PM2.5 concentration would decrease by 278 hospitalizations and ¼ US $ 190,000 in costs. CONCLUSION: An association between exposure to air pollutants and hospital admission due to Sars-Cov-2 was observed with excess hospitalization and costs for the Brazilian public health system.

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BACKGROUND: Air pollution directly interacts with airway mucosa, yet little is known about how pollutants affect upper airway inflammation. Studies have shown increased incidence of chronic rhinosinusitis (CRS), rhinitis, and asthma in areas with higher traffic pollution, and these neighborhoods are often associated with lower socioeconomic status (SES). The Area Deprivation Index (ADI) assesses neighborhood-level SES by zip code. The purpose of this study was to assess the relationship between SES and exposure to inhaled pollutants and CRS disease severity. METHODS: CRS patients with and without nasal polyps (CRSwNP and CRSsNP, respectively) were identified (total patients = 234; CRSwNP patients = 138; CRSsNP patients = 96). Pollutant concentrations, including particulate matter 2.5 (PM2.5 ), black carbon (BC), and nitrogen dioxide (NO2 ), were measured at 70 sites within the defined countywide sites and used to estimate patient exposures. SES was measured by ADI state deciles. Disease severity metrics included the modified Lund-Mackay score (LMS), the need for systemic steroids, and functional endoscopic sinus surgery (FESS). Associations were analyzed and identified using linear, logistic, and Poisson multivariable regression. RESULTS: The distribution of CRSsNP and CRSwNP patients across ADI state deciles was similar. ADI, however, was a predictor of exposure to airborne pollutants (PM2.5 , BC, and NO2 ) with a 1.39%, 2.39%, and 2.49% increase in PM2.5 , BC, and NO2 per increasing decile increment (p < 0.0001), respectively, which demonstrated a direct correlation between deprived neighborhoods and higher levels of exposure to PM2.5 , BC, and NO2 with an increase in pollutant levels per increase in ADI decile. Furthermore, ADI was a predictor for increased steroid treatment. CONCLUSION: Lower SES predicted higher exposure to air pollution and increased disease severity in patients with CRS as demonstrated by the increased need for steroid treatment.

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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.

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BACKGROUND: The Chilean Metropolitan region is exposed to nitrogen dioxide levels that are above the WHO Air Quality Guidelines. AIM: To report the exposure to nitrogen dioxide levels and to estimate the damage that these levels can cause in health. MATERIAL AND METHODS: Description of nitrogen dioxide levels in the Chilean Metropolitan Region between 2016 and 2018 and the attributable risk of these levels on the population health. RESULTS: The average hourly levels of nitrogen dioxide exceeded 40 pg/m3. In the three years studied, 11,686 attributable health problems were estimated, including deaths, hospitalizations, and attendance to emergency rooms. CONCLUSIONS: We provide valid information to review and adjust primary air quality standards for nitrogen dioxide. The exposed population should be educated about the risk of this exposure to promote self-care.

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While investigating peroxynitrite-dependent oxidation in murine RAW 264.7 macrophage cells, we observed that removal of the Labile Iron Pool (LIP) by chelation increases the intracellular oxidation of the fluorescent indicator H2DCF, so we concluded that the LIP reacts with peroxynitrite and decreases the yield of peroxynitrite-derived oxidants. This was a paradigm-shifting finding in LIP biochemistry and raised many questions. In this follow-up study, we address fundamental properties of the interaction between the LIP and peroxynitrite by using the same cellular model and fluorescence methodology. We have identified that the reaction between the LIP and peroxynitrite has catalytic characteristics, and we have estimated that the rate constant of the reaction is in the range of 106 to 107 M-1s-1. Together, these observations suggest that the LIP represents a constitutive peroxynitrite reductase system in RAW 264.7 cells.

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BACKGROUND: Air pollution is a major global public health problem. The situation is most severe in low- and middle-income countries, where pollution control measures and monitoring systems are largely lacking. Data to quantify the exposure to air pollution in low-income settings are scarce. METHODS: In this study, land use regression models (LUR) were developed to predict the outdoor nitrogen dioxide (NO2) concentration in the study area of the Western Region Birth Cohort in São Paulo. NO2 measurements were performed for one week in winter and summer at eighty locations. Additionally, weekly measurements at one regional background location were performed over a full one-year period to create an annual prediction. RESULTS: Three LUR models were developed (annual, summer, winter) by using a supervised stepwise linear regression method. The winter, summer and annual models explained 52 %, 75 % and 66 % of the variance (R2) respectively. Cross-holdout validation tests suggest robust models. NO2 levels ranged from 43.2 µg/m3 to 93.4 µg/m3 in the winter and between 28.1 µg/m3 and 72.8 µg/m3 in summer. Based on our annual prediction, about 67 % of the population living in the study area is exposed to NO2 values over the WHO suggested annual guideline of 40 µg/m3 annual average. CONCLUSION: In this study we were able to develop robust models to predict NO2 residential exposure. We could show that average measures, and therefore the predictions of NO2, in such a complex urban area are substantially high and that a major variability within the area and especially within the season is present. These findings also suggest that in general a high proportion of the population is exposed to high NO2 levels.

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BACKGROUND: There has been a notable increase in knowledge production on air pollution and human health. OBJECTIVE: To analyze the state of the art on the effects of air pollution on human health through a mapping review of existing systematic reviews and meta-analyses (SRs and MAs). METHODS: The systematic mapping review was based on the recommendations for this type of scientific approach in environmental sciences. The search was performed using PubMed, Web of Science, Scopus, Cinahl, and Cochrane Library databases, from their inception through June 2020. RESULTS: Among 3401 studies screened, 240 SRs and MAs satisfied the inclusion criteria. Five research questions were answered. There has been an overall progressive increase in publications since 2014. The majority of the SRs and MAs were carried out by researchers from institutions in China, the US, the UK, and Italy. Most studies performed a meta-analysis (161). In general, the reviews support the association of air pollution and health outcomes, and analyzed the effects of outdoor air pollution. The most commonly investigated health outcome type was the respiratory (mainly asthma and COPD), followed by cardiovascular outcomes (mainly stroke). Particulate matter (with a diameter of 2.5 µm (PM2.5) and 10 µm (PM10) or less) and nitrogen dioxide (NO2) were the most widely investigated pollutants in the reviews. The general population was the most common sample in the reviews, followed by children, and adults. The majority of the reviews investigated health outcomes of respiratory diseases in children, as well as cardiovascular diseases in all ages. Combining health outcomes and air pollutants, PM2.5 was included in a higher number of reviews in eight health outcomes, mainly cardiovascular diseases. DISCUSSION: The majority of SRs and MAs showed that air pollution has harmful effects on health, with a focus on respiratory and cardiovascular outcomes. Future studies should extend the analysis to psychological and social aspects influenced by air pollution.

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Indoor environments contribute significantly to total human exposure to air pollutants, as people spend most of their time indoors. Household air pollution (HAP) resulting from cooking with polluting ("dirty") fuels, which include coal, kerosene, and biomass (wood, charcoal, crop residues, and animal manure) is a global environmental health problem. Indoor pollutants are gases, particulates, toxins, and microorganisms among others, that can have an impact especially on the health of children and adults through a combination of different mechanisms on oxidative stress and gene activation, epigenetic, cellular, and immunological systems. Air pollution is a major risk factor and contributor to morbidity and mortality from major chronic diseases. Children are significantly affected by the impact of the environment due to biological immaturity, prenatal and postnatal lung development. Poor air quality has been related to an increased prevalence of clinical manifestations of allergic asthma and rhinitis. Health professionals should increase their role in managing the exposure of children and adults to air pollution with better methods of care, prevention, and collective action. Interventions to reduce household pollutants may promote health and can be achieved with education, community, and health professional involvement.

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BACKGROUND: Liquefied petroleum gas (LPG) stoves have been promoted in low- and middle-income countries (LMICs) as a clean energy alternative to biomass burning cookstoves. OBJECTIVE: We sought to characterize kitchen area concentrations and personal exposures to nitrogen dioxide (NO2) within a randomized controlled trial in the Peruvian Andes. The intervention included the provision of an LPG stove and continuous fuel distribution with behavioral messaging to maximize compliance. METHODS: We measured 48-hour kitchen area NO2 concentrations at high temporal resolution in homes of 50 intervention participants and 50 control participants longitudinally within a biomass-to-LPG intervention trial. We also collected 48-hour mean personal exposures to NO2 among a subsample of 16 intervention and 9 control participants. We monitored LPG and biomass stove use continuously throughout the trial. RESULTS: In 367 post-intervention 24-hour kitchen area samples of 96 participants' homes, geometric mean (GM) highest hourly NO2 concentration was 138 ppb (geometric standard deviation [GSD] 2.1) in the LPG intervention group and 450 ppb (GSD 3.1) in the biomass control group. Post-intervention 24-hour mean NO2 concentrations were a GM of 43 ppb (GSD 1.7) in the intervention group and 77 ppb (GSD 2.0) in the control group. Kitchen area NO2 concentrations exceeded the WHO indoor hourly guideline an average of 1.3 h per day among LPG intervention participants. GM 48-hour personal exposure to NO2 was 5 ppb (GSD 2.4) among 35 48-hour samples of 16 participants in the intervention group and 16 ppb (GSD 2.3) among 21 samples of 9 participants in the control group. DISCUSSION: In a biomass-to-LPG intervention trial in Peru, kitchen area NO2 concentrations were substantially lower within the LPG intervention group compared to the biomass-using control group. However, within the LPG intervention group, 69% of 24-hour kitchen area samples exceeded WHO indoor annual guidelines and 47% of samples exceeded WHO indoor hourly guidelines. Forty-eight-hour NO2 personal exposure was below WHO indoor annual guidelines for most participants in the LPG intervention group, and we did not measure personal exposure at high temporal resolution to assess exposure to cooking-related indoor concentration peaks. Further research is warranted to understand the potential health risks of LPG-related NO2 emissions and inform current campaigns which promote LPG as a clean-cooking option.

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It has been observed that air pollution can affect newborn health due to the negative effects of pollutants on pregnancy development. However, few studies have evaluated the impact of maternal exposure to urban air pollution on head circumference (HC) at birth. Reduced head growth during pregnancy may be associated with neurocognitive deficits in childhood. The objectives of this study were to evaluate the association between maternal exposure to air pollution and HC at birth and to provide context with a systematic review to investigate this association. This was a prospective study of low-risk pregnant women living in São Paulo, Brazil. Exposure to pollutants, namely, nitrogen dioxide (NO2) and ozone (O3), was measured during each trimester using passive personal samplers. We measured newborn HC until 24 h after birth. We used multiple linear regression models to evaluate the association between pollutants and HC while controlling for known determinants of pregnancy. To perform the systematic review, four different electronic databases were searched through November 2018: CENTRAL, EMBASE, LILACS, and MEDLINE. We selected longitudinal or transversal designs associating air pollution and HC at birth. Two reviewers evaluated the inclusion criteria and risk of bias and extracted data from the included papers. Thirteen studies were selected for the systematic review. We evaluated 391 patients, and we did not observe a significant association between air pollution and HC. Regarding the systematic review, 13 studies were selected for the systematic review, 8 studies showed an inverse association between maternal exposure to pollutants and HC, 4 showed no association, and one observed a direct association. In the city of São Paulo, maternal exposure to pollutants was not significantly associated with HC at birth. The systematic review suggested an inverse association between air pollution and HC at birth.

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On March 24, 2020, a partial lockdown was decreed in the state of São Paulo, Brazil, as a measure to hinder the spread of COVID-19, which consisted in prohibiting crowding and advising people to stay home, except for urgent or extremely necessary matters. Based on studies performed in other countries, this study aims to assess the impacts of the lockdown on the air quality of five cities in the state of São Paulo. Our study was conducted by using particulate matter and nitrogen dioxide as air quality indicators, and by correlating the contaminants concentrations with weather data. The results showed an increase in these contaminants in all cities within the first weeks after the lockdown compared with the weeks before the decree and with the same period in previous years. This result is inconsistent with the literature. Therefore, a secondary goal was set to investigate the possible cause (or causes) of such deterioration in air quality, which led to the increased number of wildfires. The anomalous dry weather favored the burning of vegetation in agricultural rural areas and in small, vegetated areas near the municipalities, and limited pollution scavenging by rainfall, both of which contributed to higher pollution concentration. We hypothesize the possible effects of worse air quality on the aggravation of COVID-19, but further research is necessary to obtain a complete assessment.

Em 24 de março de 2020, foi decretado confinamento parcial no Estado de São Paulo, Brasil, como medida para desacelerar a disseminação da COVID-19. O decreto consistia na proibição de aglomerações e na recomendação para as pessoas permanecerem em casa, exceto em situações urgentes ou de extrema necessidade. Na esteira de estudos realizados em outros países, o artigo busca avaliar os impactos do confinamento na qualidade do ar em cinco cidades no Estado de São Paulo. Nosso estudo foi realizado com o material particulado e dióxido de nitrogênio enquanto indicadores da qualidade do ar e pela correlação das concentrações dos contaminantes com dados meteorológicos. Os resultados mostraram um aumento desses contaminantes em todas as cinco cidades dentro das primeiras semanas depois do confinamento, comparado às semanas que antecederam o decreto e com o mesmo período em anos anteriores. O resultado é inconsistente com os achados usualmente relatados em outros estudos. Portanto, foi definido um objetivo secundário a fim de investigar a possível causa (ou causas) da piora na qualidade do ar, o que revelou um aumento no número de incêndios. O tempo anormalmente seco favoreceu a queima de vegetação nas áreas agrícolas rurais e em pequenas áreas de vegetação próximas às cidades, além do limitado escoamento da poluição pela chuva, o que contribuiu à maior concentração de poluentes. Os achados sugerem hipóteses sobre os possíveis efeitos dessa situação de pior qualidade do ar sobre o agravamento de casos de COVID-19, porém são necessários mais estudos para uma avaliação completa.

El 24 de marzo de 2020 se decretó un confinamiento parcial en el estado de São Paulo, Brasil, como medida para evitar la propagación de la COVID-19, que consistió en prohibir aglomeraciones de personas y avisar a la gente que permaneciera en casa, salvo para asuntos urgentes o extremadamente necesarios. Siguiendo algunos estudios realizados en otros países, el objetivo de este trabajo es evaluar los impactos del confinamiento en la calidad del aire de ciudades en el estado de São Paulo. Nuestro estudio fue realizado usando material particulado y dióxido de nitrógeno, como indicadores de la calidad del aire, y mediante la correlación de las concentraciones de contaminantes con los datos meteorológicos. Los resultados mostraron un incremento en estos contaminantes en todas las ciudades dentro de las primeras semanas tras el confinamiento, comparando las semanas antes del decreto y dentro del mismo periodo en los años previos. Este resultado es inconsistente con aquellos que han sido informados en otros estudios. Por ello, un objetivo secundario fue investigar la posible causa (o causas) de tal deterioro en la calidad del aire, que conduce a un incremento en el número de incendios. La climatología seca anómala favoreció la quema de vegetación en las áreas rurales agrícolas, y en áreas con poca vegetación cerca de las ciudades, y la eliminación limitada de la contaminación gracias a la lluvia, ambos contribuyeron a una mayor concentración de contaminación. Se especula que los posibles efectos de esta situación de una peor calidad del aire podrían afectar en el agravamiento de los casos de COVID-19, pero son quizás necesarias más investigaciones para conseguir una evaluación completa.

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The negative effects on human health, along with the fatalities caused by the new coronavirus, have led governments worldwide to take strict measures. However, a reduction in air pollution has been found in many regions on a global scale. This study is focused on how the COVID-19 pandemic is impacting on the air quality in Ecuador, one of the most alarming cases of COVID-19 contagion in Latin America, occupying the first place as regards deaths per capita. The spatio-temporal variations in NO2 concentrations in 12 highly populated cities were evaluated by comparing the NO2 tropospheric concentrations before (2019) and after (2020) the COVID-19 lockdown. The atmospheric data was collected from the TROPOMI on the Sentinel-5P satellite of the European Space Agency. A reduction in NO2 concentrations (-13%) was observed as a consequence of the COVID-19 lockdown in Ecuador. However, this reduction occurred to the greatest extent in the cases of Guayaquil (-23.4%) and Quito (-22.4%), the two most highly populated cities. Linking NO2 levels to confirmed cases/deaths of COVID-19, a strong correlation between air NO2 concentrations and the cases/mortality caused by coronavirus (r = 0.91; p<0.001) was observed. This work highlights the crucial role played by air quality as regards human health.

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The first COVID-19 case in Brazil was confirmed on February 25, 2020. Partial lockdown measures came into force in the city of Rio de Janeiro, Brazil, on March 23. While CO and NO2 levels showed significant reductions, PM10 levels were only reduced in the first partial lockdown week. By contrast, ozone levels increased in all studied locations. In this study, the factors leading to this behavior were analyzed. Monitoring data obtained at two automatic monitoring stations showed higher ratios between non-methane hydrocarbons and nitrogen oxides (NMHC/NOx) during the partial lockdown (up to 37.3%). The increase in ozone concentrations during the social distancing measures could be attributed to the increase in NMHC/NOx ratios since atmospheric chemistry in Rio de Janeiro is under VOC-controlled conditions. However, the increase was higher when air masses arrived from the industrial areas, not only because of the higher NMHC/NOx ratios, but also because the reactivity of VOC was highly increased by these air masses, which are rich in aromatic compounds.

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