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The novel coronavirus disease 2019 (COVID-19), which first emerged in Hubei province, China, has become a pandemic. However, data regarding the effects of meteorological factors on its transmission are limited and inconsistent. A mechanism-based parameterisation scheme was developed to investigate the association between the scaled transmission rate (STR) of COVID-19 and the meteorological parameters in 20 provinces/municipalities located on the plains in China. We obtained information on the scale of population migrated from Wuhan, the world epicentre of the COVID-19 outbreak, into the study provinces/municipalities using mobile-phone positioning system and big data techniques. The highest STRs were found in densely populated metropolitan areas and in cold provinces located in north-eastern China. Population density had a non-linear relationship with disease spread (linearity index, 0.9). Among various meteorological factors, only temperature was significantly associated with the STR after controlling for the effect of population density. A negative and exponential relationship was identified between the transmission rate and the temperature (correlation coefficient, −0.56; 99% confidence level). The STR increased substantially as the temperature in north-eastern China decreased below 0 °C (the STR ranged from 3.5 to 12.3 when the temperature was between −9.41 °C and −13.87 °C), whilst the STR showed less temperature dependence in the study areas with temperate weather conditions (the STR was 1.21 ± 0.57 when the temperature was above 0 °C). Therefore, a higher population density was linearly whereas a lower temperature (, Graphical abstract Unlabelled Image, Highlights • A mechanism-based parameterisation scheme was developed for transmission rate. • Scale of population migration from Wuhan was incorporated. • Population density had a non-linear (linearity index, 0.9) impact on disease spread. • Transmission rate shows a negative and exponential temperature dependence. • COVID-19 mitigation in densely populated and cold regions will be a great challenge.

School-age children are particularly susceptible to exposure to air pollutants. To quantify factors affecting children's exposure at school, indoor and outdoor microenvironmental air pollutant concentrations were measured at 32 selected primary and secondary schools in Hong Kong. Real-time PM10 , PM2.5 , NO2, and O3 concentrations were measured in 76 classrooms and 23 non-classrooms. Potential explanatory factors related to building characteristics, ventilation practice, and occupant activities were measured or recorded. Their relationship with indoor measured concentrations was examined using mixed linear regression models. Ten factors were significantly associated with indoor microenvironmental concentrations, together accounting for 74%, 61%, 46%, and 38% of variations observed for PM2.5 , PM10 , O3, and NO2 microenvironmental concentrations, respectively. Outdoor concentration is the single largest predictor for indoor concentrations. Infiltrated outdoor air pollution contributes to 90%, 70%, 75%, and 50% of PM2.5 , PM10 , O3, and NO2 microenvironmental concentrations, respectively, in classrooms during school hours. Interventions to reduce indoor microenvironmental concentrations can be prioritized in reducing ambient air pollution and infiltration of outdoor pollution. Infiltration factors derived from linear regression models provide useful information on outdoor infiltration and help address the gap in generalizable parameter values that can be used to predict school microenvironmental concentrations.

The majority of urban residents live in places with air quality exceeding World Health Organization guidelines. To quantify infiltration of outdoor pollution, and key factors affecting it, common outdoor air pollutants (PM2.5, NO2, and O3) were measured at 49 homes in Hong Kong. Infiltration factors (Finf) were derived based on linear regression of simultaneous indoor and outdoor measurements for each pollutant at each home. Finf estimated based on data for home occupancy, during which people were actually exposed, differed by up to 22%, 73% and 63% for PM2.5, NO2 and O3, respectively, from estimates based on whole monitoring data. This indicates the importance of separating occupancy time to quantify Finf for exposure estimation. The inter-home variability in occupancy Finf ranged from 0.11 to 1.00 (mean: 0.75) for PM2.5, 0.14 to 1.00 (mean: 0.53) for NO2, and 0.05 to 0.95 (mean: 0.47) for O3. Ventilation practices (e.g., window opening duration and air-conditioning on/off) explained 48%, 20%, and 10% of the inter-home variations in PM2.5, NO2 and O3 Finf, respectively. Use of air purifiers explained an additional 8%–9% of variations for PM2.5 and NO2. Thus, there is potential to reduce outdoor infiltration by modifying occupant behaviours. Compared to PM2.5 (R2 = 0.63), the developed models explained less variability in Finf for NO2 (R2 = 0.40) and O3 (R2 = 0.10). These two gases are chemically reactive. Further investigation, supported by additional measurements of related chemical species, is needed to improve understanding of infiltration process of reactive gases such as NO2 and O3.

Background. Heavy metals contamination of food is a serious threat. Long term exposure may lead to human health risks. Poultry and eggs are a major source of protein, but if contaminated by heavy metals, have the potential to lead to detrimental effects on human health. Objectives. The objective of this study is to determine chromium concentrations in poultry meat (flesh and liver) and eggs collected from poultry farms in Dhaka, Bangladesh, to calculate the daily intake of chromium from the consumption of poultry meat and eggs for adults, and to evaluate their potential health risk by calculating the target hazard quotients (THQ). Methods. All samples of poultry feed, meat (flesh and liver) and eggs were analyzed by a graphite furnace atomic absorption spectrometer (AAS) (GFA- EX- 7i Shimadju, Japan). Results. Chromium concentrations were recorded in the range of not detected (ND) to 1.3926±0.0010 mg kg−1 and 0.0678±0.0001 mg kg−1 to 1.3764±0.0009 mg kg−1 in the liver of broiler and layer chickens, respectively. Chromium concentrations were determined in the range of 0.069±1.0004 mgkg−1 to 2.0746±0.0021 mg kg−1 and 0.0362±0.0002 mg kg−1 to 1.2752±0.0014 mg kg−1 in the flesh of broiler and layer chicken, respectively. The mean concentration of chromium in eggs was 0.2174−1.08 mg kg.−1 The highest concentration of chromium 2.4196±0.0019 mg kg−1 was found in egg yolk. Target hazard quotients values in all poultry flesh, liver and eggs samples were less than one, indicating no potential health risks to consumers. Conclusions. The estimated daily intake values of chromium were below the threshold limit. Thus, our results indicate that no adverse health effects are expected as a resultof ingestion of chicken fed with tannery waste. Competing Interests. The authors declare no competing financial interests. Ethics Approval: This study was approved by the Biosafety, Biosecurity & Ethical Committee of Jahangirnagar University.

Household air pollution (HAP) is one of the most important global environmental and public health issues. As a result of changes in air composition due to rapid industrialization and urbanization, air quality is deteriorating and outdoor pollution is increasing daily. Simultaneously, poor ventilation, microbial growth, tobacco smoke, solid fuel use, and different toxic chemicals are causing deterioration in household air quality, which contributes significantly to the global burden of disease. This paper reviews the available literature to examine the impact of HAP on human health, comprehensively identifies the sources of HAP, and synthesize management approaches to reducing the severity of HAP. The English language databases PubMed, Google Scholar, Web of Science, and Science Direct were searched using the key terms: HAP, particulate matter, health risks, public health, pollutant sources, burden of diseases, and management approach. Bibliographies of all relevant articles were also screened to find further useful articles. This review addresses all possible sources of HAP that are categorized as biological or chemical (organic and inorganic) and are associated with grave public health threats, such as lung function reduction, respiratory illness, asthma, pneumonia, tuberculosis, eye diseases, pregnancy complications, cardiovascular diseases, and cancer. Suggested approaches, including compliance with international guidelines and regulatory frameworks, pollutant source reduction methods, and fulfillment of international environmental laws, conventions, agreements, protocols, and treaties, can be effectively adopted to mitigate household air pollutants, reduce the global burden of disease, and promote household environments that support better human health. The sources of HAP and its health impacts should be considered in the development of future policies concerning reduction in all household air pollutants worldwide. Therefore, this review establishes the groundwork for future studies assessing the effectiveness of strategies aimed at creating sound household environments to promote better human health.

Governments may relax physical distancing interventions for coronavirus disease 2019 (Covid-19) containment in warm seasons/areas to prevent economic contractions. However, it is not clear whether higher temperature may offset the transmission risk posed by this relaxation. This study aims to investigate the associations of the effective reproductive number (Rt) of Covid-19 with ambient temperature and the implementation of physical distancing interventions in the United States (US). This study included 50 states and one territory of the US with 4,532,650 confirmed cases between 29 January and 31 July 2020. We used an interrupted time-series model with a state-level random intercept for data analysis. An interaction term of ‘physical distancing×temperature’ was included to examine their interactions. Stratified analyses by temperature and physical distancing implementation were also performed to analyse the modifying effects. The overall median (interquartile range) Rt was 1.2 (1.0–2.3). The implementation of physical distancing was associated with a 12% decrease in the risk of Rt (relative risk [RR]: 0.88, 95% confident interval [CI]: 0.86–0.89), and each 5 °C increase in temperature was associated with a 2% decrease (RR: 0.98, 95%CI: 0.97–0.98). We observed a statistically significant interaction between temperature and physical distancing implementation, but all the RRs were small (close to one). The containing effects of high temperature were attenuated by 5.1% when physical distancing was implemented. The association of COVID-19 Rt with physical distancing implementation was more stable (0.88 vs. 0.89 in days when temperature was low and high, respectively). Increased temperature did not offset the risk of Covid-19 Rt posed by the relaxation of physical distancing implementation. Our study does not recommend relaxing the implementation of physical distancing interventions in warm seasons/areas., Graphical abstract Unlabelled Image

O3 pollution had been worsening in mainland China in the past decade, posing significant human health challenges. The NOx control would trigger increasing O3 concentrations in response to a series of released China emission reduction policies. This study used sensitivity analysis methodology to explore the effectiveness of integrated sectoral emission control policies that have been expanded throughout China. Air quality and synergistic health effects of O3 and NO2 were investigated to obtain an in-depth understanding of the O3 control, especially under a VOC-limited regime. The findings demonstrated that although the NOx-titration effect triggered an increase in O3, the combined health effects of two pollutants tended to improve in most regions of China under a VOC-limited regime. The region-based annual average NO2 concentrations exhibited a larger reduction in Hong Kong (HK) than in the Pearl River Delta Economic Zone (PRD EZ). The short-term measures led to substantial health benefits for Shenzhen and HK. The sectoral emission controls demonstrated a considerable health improvement for the major PRD EZ cities. Joint national control efforts confined the domain-wide health risks below the safety line in China. National cooperative efforts in China could avoid more than 1.5-2% of the emergency hospital admissions for cardiovascular and respiratory diseases attributed to NO2 and O3 exposure. The observed O3 increases due to the NOx-titration effect for calculating the integral health effects of emission control on concentration reduction called for simultaneously strengthened controls on both NOx and VOC in areas subject to a VOC-limited regime.

Novel corona virus disease 2019 (COVID-19), which first emerged in December 2019, has become a pandemic. This study aimed to investigate the associations between meteorological factors and COVID-19 incidence and mortality worldwide. This study included 1,908,197 confirmed cases of and 119,257 deaths from COVID-19 from 190 countries between 23 January and 13 April, 2020. We used a distributed lag non-linear model with city-/country-level random intercept to investigate the associations between COVID19 incidence and daily temperature, relative humidity, and wind speed. A series of confounders were considered in the analysis including demographics, socioeconomics, geographic locations, and political strategies. Sensitivity analyses were performed to examine the robustness of the associations. The COVID-19 incidence showed a stronger association with temperature than with relative humidity or wind speed. An inverse association was identified between the COVID-19 incidence and temperature. The corresponding 14-day cumulative relative risk was 1.28 [95% confidence interval (CI), 1.20–1.36] at 5 °C, and 0.75 (95% CI, 0.65–0.86) at 22 °C with reference to the risk at 11 °C. An inverse J-shaped association was observed between relative humidity and the COVID-19 incidence, with the highest risk at 72%. A higher wind speed was associated with a generally lower incidence of COVID-19, although the associations were weak. Sensitivity analyses generally yielded similar results. The COVID-19 incidence decreased with the increase of temperature. Our study suggests that the spread of COVID-19 may slow during summer but may increase during winter., Graphical abstract Unlabelled Image, Highlights • A higher temperature was associated with a lower incidence of COVID-19. • The spread of COVID-19 may slow during summer but may increase during winter. • There was an inverse J-shaped association between relative humidity and the incidence of COVID-19. • The association between wind speed and the incidence of COVID-19 was nonlinear.

Ship breaking or recycling in Bangladesh has been a catalyst for the economy by supporting the steel, shipbuilding, furniture, building construction, machinery and electrical industries since the 1980s. Although it has generated huge employment and provided 80–90% of the total steel consumption in the country, it has faced a host of challenges due to a number of negative environmental and social impacts that hinder the sustainable development of this blooming sector. The objective of this paper is to focus on how ship-breaking activities in Bangladesh affect the adjacent environment and the health and safety of workers, as well as management’s approach to the sustainability of the industry, by conducting a review of the available scientific literature. We found that grave environmental pollution, such as physiochemical properties, heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl compounds (PCBs), organotins, oil and grease pollution, asbestos and other atmospheric pollutants, and its impact on marine ecosystems, biodiversity, forestry, fisheries and human health are the main obstacles for the development of a sustainable ship-breaking industry. In addition, labour safety and occupational health problems, social unrest and conflicts have resulted from the development of the ship-breaking industry in Bangladesh. Inappropriate management practices and inadequate plans regarding ship-breaking activities and processes are the main reasons for these challenges. Effective management measures to mitigate the adverse environmental impact of the ship-breaking industry and to improve the health and safety of workers have now become an urgent requirement.

Background. Wastewater is often used in developing countries for irrigation of crops. This wastewater often contains a number of heavy metals which are harmful to human health due to their non-biodegradable nature, long biological half-lives and their potential to accumulate in different body parts. There are many potential risks to human health from heavy metal contamination of vegetables grown at waste-water-irrigated sites. Objectives. This study was carried out to assess the concentration of heavy metals and the risk to human health by heavy metals (lead (Pb), nickel (Ni) and arsenic (As)) through the intake of locally grown vegetables collected from wastewater irrigated agricultural fields. The objectives of the present study were to determine concentrations of heavy metals in vegetables collected from the wastewater-irrigated fields, to calculate daily intake of heavy metals from the consumption of vegetables for both adults and children, and to evaluate their potential health risk. Methods. Twenty-seven samples of nine different types of vegetables were analyzed by an Atomic Absorption Spectrometer (AAS) (Varian AAS 240 F S). Results. The range of various metals in waste-water irrigated vegetables were not detected (ND)-0.188, 0.072–1.069 and ND-0.076 mg/kg for Pb, Ni and As, respectively. The highest mean concentration of all metals was detected in jute leaf, except for Pb which was found in the stem amaranth leaf. The mean concentration of all metals in all vegetables was within the safe limits of the World Health Organization/Food and Agricultural Organization (WHO/FAO) and China's national standards. The health risk index was more than 1 for As in jute leaf for both adults and children. The metal pollution index was highest (0.16 mg/kg) in jute leaf, whereas green papaya showed the lowest metal pollution index (MPI) value (0.005 mg/kg). Among all vegetables tested, the highest intake values of Ni and As were from consumption of jute leaf and the highest intake values of Pb from consumption of stem amaranth leaf for both adults and children. Conclusions. Higher values in the metal pollution index and health risk index indicate heavy metal contamination in wastewater-irrigated soils that present the potential for a significant negative impact on human health.

The frozen food export sector, next to readymade garments sector, is the second largest export earner of Bangladesh. Shrimp, main item of frozen food, is a major contributor in the national economy of Bangladesh since mid 1980s. Although it provides millions of employment and earns more than US$ 445 million annually, it has been facing a host of challenges. Shrimp farming has been associated with a number of negative environmental and social impacts which hinder the sustainable development of this blooming sector. This paper aim to focus on how the shrimp culture in Bangladesh is affecting the adjacent environment as well as society and management approach for it’s sustain ability by means of reviewing the available scientific literatures. It finds the grave socioeconomic impacts including traditional livelihood displacement, loss of land security, food insecurity, marginalization, rural unemployment, social unrest and conflicts in the wake of shrimp culture development in Bangladesh. Similarly, environmental impacts such as mangrove degradation, loss of biodiversity, sedimentation, saltwater intrusion, and pollution and disease outbreaks are found to be the main obstacles for the development of sustainable shrimp farming. Inappropriate management practices and inadequate plans regarding water quality, seed supply, irrigation facilities and fishery resources are the main reasons for these impacts of shrimp farming. The effective management measures to mitigate the adverse environmental impact of shrimp farming development have now become urgent requirement.