SARS-CoV-2: a systematic review of indoor air sampling for virus detection.

In a post-pandemic scenario, indoor air monitoring may be required seeking to safeguard public health, and therefore well-defined methods, protocols, and equipment play an important role. Considering the COVID-19 pandemic, this manuscript presents a literature review on indoor air sampling methods to detect viruses, especially SARS-CoV-2. The review was conducted using the following online databases: Web of Science, Science Direct, and PubMed, and the Boolean operators "AND" and "OR" to combine the following keywords: air sampler, coronavirus, COVID-19, indoor, and SARS-CoV-2. This review included 25 published papers reporting sampling and detection methods for SARS-CoV-2 in indoor environments. Most of the papers focused on sampling and analysis of viruses in aerosols present in contaminated areas and potential transmission to adjacent areas. Negative results were found in 10 studies, while 15 papers showed positive results in at least one sample. Overall, papers report several sampling devices and methods for SARS-CoV-2 detection, using different approaches for distance, height from the floor, flow rates, and sampled air volumes. Regarding the efficacy of each mechanism as measured by the percentage of investigations with positive samples, the literature review indicates that solid impactors are more effective than liquid impactors, or filters, and the combination of various methods may be recommended. As a final remark, determining the sampling method is not a trivial task, as the samplers and the environment influence the presence and viability of viruses in the samples, and thus a case-by-case assessment is required for the selection of sampling systems.

COVID-19 pandemic: Solid waste and environmental impacts in Brazil.

The World Health Organization has recently declared South America the new epicenter of the COVID-19 pandemic, as Brazil has become one of the most affected countries. Besides public health and economic impacts, social isolation has also caused indirect environmental effects. The aim of this study was to assess environmental impacts caused by shifts on solid waste production and management due to the COVID-19 pandemic in Brazil. We have analyzed data from 30 cities, representing a population of more than 53.8 million people (25.4% of the Brazilian population). Unexpectedly, solid waste production in the main cities in Brazil has decreased during the social isolation period, possibly because of reduced activity in commercial areas. The latest data on solid waste in Brazil have revealed that more than 35% of medical waste has not been treated properly. Furthermore, improper disposal of facemasks has been reported in several cities and may increase the risk for COVID-19 spread. The suspension of recycling programs has hindered natural resources from being saved, with emphasis on 24,076 MWh of electric power and 185,929 m3 of potable water - respectively enough to supply 152,475 households and 40,010 people, over a month. Furthermore, total sale price for recyclable materials during the suspension of recycling programs reaches more than 781 thousand dollars, being these materials disposed in landfills - demanding an extra volume of 19,000 m3 - reducing landfill lifespan, and hence causing a double loss: economic and environmental.

COVID-19 pandemic: environmental and social factors influencing the spread of SARS-CoV-2 in São Paulo, Brazil.

The new coronavirus SARS-CoV-2 has infected more than 14 million people worldwide so far. Brazil is currently the second leading country in number of cases of COVID-19, while São Paulo state accounts for 20% of total confirmed cases in Brazil. The aim of this study was to assess environmental and social factors influencing the spread of SARS-CoV-2 in the expanded metropolitan area of São Paulo, Brazil. Firstly, a spatial analysis was conducted to provide insights into the spread of COVID-19 within the expanded metropolitan area. Moreover, Spearman correlation test and sensitivity analysis were performed to assess social indicators and environmental conditions which possibly influence the incidence of COVID-19. Our results reveal that the spread of COVID-19 from the capital city São Paulo-its epicenter in Brazil-is directly associated with the availability of highways within the expanded metropolitan area of São Paulo. As for social aspects, COVID-19 infection rate was found to be both positively correlated with population density, and negatively correlated with social isolation rate, hence indicating that social distancing has been effective in reducing the COVID-19 transmission. Finally, COVID-19 infection rate was found to be inversely correlated with both temperature and UV radiation. Together with recent literature our study suggests that the UV radiation provided by sunlight might contribute to depletion of SARS-CoV-2 infectivity.

GIS-based spatial modelling of COVID-19 death incidence in São Paulo, Brazil.

Seeking to understand the socio-spatial behaviour of the COVID-19 virus in the most impacted area in Brazil, five spatial regression models were analysed to assess the disease distribution in the affected territory. Results obtained using the Spearman correlation test provided evidence for the correlation between COVID-19 death incidence and social aspects such as population density, average people per household, and informal urban settlements. More importantly, all analysed models using four selected explanatory variables have proven to represent at least 85 per cent of reported deaths at the district level. Overall, our results have demonstrated that the geographically weighted regression (GWR) model best explains the spatial distribution of COVID-19 in the city of São Paulo, highlighting the spatial aspects of the data. Spatial analysis has shown the spread of COVID-19 in areas with highly vulnerable populations. Our findings corroborate reports from the recent literature, pointing out the need for special attention in peripheral areas and informal settlements.

COVID-19 pandemic: Impacts on the air quality during the partial lockdown in São Paulo state, Brazil.

In early March 2020, the World Health Organization declared the COVID-19 as a pandemic, and in late March 2020 partial lockdown was ordered by the São Paulo state government. The aim of this study was to assess impacts on air quality in São Paulo - Brazil, during the partial lockdown implemented to provide social distancing required due to the COVID-19 pandemic. We have analyzed data from four air quality stations in São Paulo, Brazil to assess air pollutant concentration variations during the partial lockdown. Data were compared to the five-year monthly mean and to the four-week before the partial lockdown. Overall, drastic reductions on NO (up to -77.3%), NO2 (up to -54.3%), and CO (up to -64.8%) concentrations were observed in the urban area during partial lockdown compared to the five-year monthly mean. By contrast, an increase of approximately 30% in ozone concentrations was observed in urban areas highly influenced by vehicle traffic, probably related to nitrogen monoxide decreases. Although the partial lockdown has contributed to a positive impact on air quality, it is important to take into account the negative impacts on social aspects, considering the deaths caused by COVID-19 and also the dramatic economic effects.

Pre-ozonation of source water: Assessment of efficacy against Giardia duodenalis cysts and effects on natural organic matter.

The protozoan Giardia duodenalis is one of the parasites of primary concern in drinking water treatment plants, due to its resistance to chlorination. Another matter of concern regarding chlorination of drinking water is the formation of disinfection by-products in the presence of precursors such as natural organic matter (NOM). In this study, the effects of ozonation (5 mg L-1) on G. duodenalis cysts in raw surface water from a drinking water treatment plant were evaluated, and the presence and alteration of NOM were assessed, as an indicative of the potential to prevent total organic halogen (TOX) formation during post-chlorination. Following ozone treatment, the presence of damaged cysts was observed by direct immunofluorescence assay (IFA) and confirmed by the molecular approach propidium monoazide-polymerase chain reaction (PMA-PCR). Using an animal model, analysis of the intestinal tissues revealed that 80% of the animals inoculated with ozonated water were positive for trophozoites. This study shows that analysis of intestinal fragments is imperative to accurately assess animal infection following inoculation of treated cysts. More importantly, considering the low infective dose of Giardia cysts in susceptible hosts, an ozone dosage usually applied in drinking water treatment plants did not completely inactivate G. duodenalis cysts in surface water. Nonetheless, the results suggest that competitive reactions with NOM have occurred, and the applied ozone dosage has proven useful to remove NOM reactivity, and thus prevent halogenated DBP formation during post-chlorination.

Variabilidade qualitativa de aguas pluviais coletadas em telhado e sua importancia na concepcao do sistema de tratamento / Qualitative variability of roof harvested rainwater and its importance for the conception of treatment system

O presente trabalho teve como objetivo estudar a qualidade e a variabilidade de águas pluviais escoadas e armazenadas. Foram realizadas análises estatísticas descritivas, correlacionais e de componentes principais. As coletas de águas pluviais foram feitas nas dependências da Universidade Estadual Paulista "Júlio de Mesquita Filho", situada no campus de Rio Claro. Para este estudo, foram utilizadas amostras de 43 precipitações, coletadas entre março de 2010 e abril de 2012. Os resultados apontam que a concepção de sistemas de tratamento de águas pluviais deve ser realizada considerando a grande variabilidade de qualidade entre eventos de chuva. Os resultados da análise de componentes principais indicam que a grande variabilidade das águas pluviais coletadas é influenciada, sobretudo, pela deposição de sólidos durante o período de estiagem e pela decomposição de matéria orgânica, requerendo tecnologias de operação flexíveis.

The aim of the present work was to study the quality and variability of runoff and stored rainwater. Descriptive statistical, correlational, and principal component analyses were performed. The rainwater samples were taken from the buildings of São Paulo State University "Júlio de Mesquita Filho", located in Rio Claro. For the present study, samples from 43 rain events were used, which had been collected from March 2010 to April 2012. The results indicate that the conception of rainwater treatment systems must consider the high variability of rainfall quality. The results from the principal components analysis indicate that solids deposition during dry periods and the organic matter decomposition are the main factors affecting the variability of harvested rainwater, thus requiring operationally flexible technologies.