To estimate effect of COVID-19 control measures taken to mitigate community transmission in many regions, we analyzed data based on influenza surveillance system in Beijing from week 27th, 2014 to ...week 26th, 2020. We collected weekly number of influenza-like illness (ILI), weekly positive proportion of ILI and weekly ILI proportion in outpatients and the date of COVID-19 measures. We compared influenza activity indicators of season 2019/2020 with preceding five seasons and built two ARIMAX models to estimate the effective of COVID-19 measures which emergency response declared since 24th January 2020. Based on observed data, compared with preceding five influenza seasons, ILIs, positive proportion of ILI, and duration of influenza epidemic period in season 2019/2020 decreased from 13% to 54%, especially, the number of weeks from the peak to the end of influenza epidemic period, decreased from 12 to one. Based ARIMAX model forecasting, after natural decline considered, weekly ILIs decreased by 48.6% and weekly positive proportion dropped 15% in the second week after emergency response declared, and finally COVID-19 measures reduced 83%. We conclude public health emergency response can interrupt the transmission of influenza markedly.
An increasing number of countries are investigating options to stop the spread of the emerging zoonotic infection Salmonella (S.) Dublin, which mainly spreads among bovines and with cattle manure. ...Detailed surveillance and cattle movement data from an 11-year period in Denmark provided an opportunity to gain new knowledge for mitigation options through a combined social network and simulation modeling approach. The analysis revealed similar network trends for non-infected and infected cattle farms despite stringent cattle movement restrictions imposed on infected farms in the national control program. The strongest predictive factor for farms becoming infected was their cattle movement activities in the previous month, with twice the effect of local transmission. The simulation model indicated an endemic S. Dublin occurrence, with peaks in outbreak probabilities and sizes around observed cattle movement activities. Therefore, pre- and post-movement measures within a 1-mo time-window may help reduce S. Dublin spread.
Microplastics are plastic particles which are widely distributed in the environment. The pollution of microplastics in environment have attracted increasing attention in recent years. This paper ...reviews research progress in sources, analytical methods, eco-environmental effects and control in environment, and suggests relevant countermeasures in governance and research. Microplastics mainly originate from two sources: firstly, a significant direct input of primary microplastics; second, secondary microplastics generate from the fragmentations of larger plastic materials. The analysis and identification of microplastics are critical to other researches, and related instrument methods have also been applied to the analysis and identification of microplastics. The advantages and disadvantages of microplastics analytical methods were reviewed. The eco-environmental effects of microplastics can be divided into four aspects: adsorption, biological uptake, ecotoxicological and combined pollution. Control measures need to strengthen the systematic research of microplastics pollution control and management technology system from the aspects of organizational cooperation, technological research and development, laws and regulations. In the future, a unified quantitative analysis method for microplastics should be established, and more accurate traceability analysis techniques should be developed to further explore its environmental behavior and fate. To strengthen scientific research on microplastic pollution in terrestrial, freshwater and atmospheric environments, and develop more scientific and rational control policies. This paper aims to provide a theoretical basis for the prevention and control of microplastics pollution, and also provides insights for the next step of research.
•Microplastics pollution as a new environmental problem has attracted wide attention.•Recent advances in pollution research of microplastics have been reviewed.•The source and distribution of microplastics in environment are discussed.•Eco-environmental effects and control measures of microplastics are discussed.
Airborne Volatile organic compounds (VOCs) are known to have strong and adverse impacts on human health and the environment by contributing to the formation of tropospheric ozone. VOCs can escape ...during various stages of crude oil processing, from extraction to refinery, hence the crude oil industry is recognised as one of the major sources of VOC release into the environment. In the last few decades, volatile emissions from crude oil have been investigated either directly by means of laboratory and field-based analyses, or indirectly via emission inventories (EIs) which have been used to develop regulatory and controlling measures in the petroleum industry. There is a vast amount of scattered data in the literature for both regional emissions from crude oil processing and scientific measurements of VOC releases. This paper aims to provide a critical analysis of the overall scale of global emissions of VOCs from all stages of oil processing based on data reported in the literature. The volatile compounds, identified via EIs of the crude oil industry or through direct emissions from oil mass, are collected and analysed to present a global-scale evaluation of type, average concentration and detection frequency of the most prevalent VOCs. We provide a critical analysis on the total averages of VOCs and key pieces of evidence which highlights the necessity of implementing control measures to regulate crude oil volatile emissions (CVEs) in primary steps of extraction-to-refinery pathways of crude oil processing. We have identified knowledge gaps in this field which are of importance to control the release of VOCs from crude oil, independent of oil type, location, operating conditions and metrological parameters.
Display omitted
•The Middle East, Central Africa, Russia and Latin America lack up-to-date CVEs.•Access to cost-effective real-time monitoring devices for VOC detections is urgent.•VOC emissions are less controlled during crude oil extraction stage (well-to-tank).•Extensive knowledge gap in occupational exposure limits and control measures exist.•Toluene, benzene, hexane, heptane, cyclohexane are high detected concentrated CVEs.
Urban street canyons formed by high-rise buildings restrict the dispersion of vehicle emissions, which pose severe health risks to the public by aggravating roadside air quality. However, this issue ...is often overlooked in city planning. This paper reviews the mechanisms controlling vehicle emission dispersion in urban street canyons and the strategies for managing roadside air pollution. Studies have shown that air pollution hotspots are not all attributed to heavy traffic and proper urban design can mitigate air pollution. The key factors include traffic conditions, canyon geometry, weather conditions and chemical reactions. Two categories of mitigation strategies are identified, namely traffic interventions and city planning. Popular traffic interventions for street canyons include low emission zones and congestion charges which can moderately improve roadside air quality. In comparison, city planning in terms of building geometry can significantly promote pollutant dispersion in street canyons. General design guidelines, such as lower canyon aspect ratio, alignment between streets and prevailing winds, non-uniform building heights and ground-level building porosity, may be encompassed in new development. Concurrently, in-street barriers are widely applicable to rectify the poor roadside air quality in existing street canyons. They are broadly classified into porous (e.g. trees and hedges) and solid (e.g. kerbside parked cars, noise fences and viaducts) barriers that utilize their aerodynamic advantages to ease roadside air pollution. Post-evaluations are needed to review these strategies by real-world field experiments and more detailed modelling in the practical perspective.
Display omitted
•Key influences are canyon geometry, traffic and weather conditions, and chemical reactions.•Traffic interventions in street canyons lead to moderate improvement of roadside air quality.•Well-designed canyon geometry significantly enhances dispersion of emissions.•Combining solid and porous in-street barriers is more effective than individual use.•Traffic control and in-street barriers are more implementable than canyon geometry design.
The reduction of NOx emissions in a VOC-limited region can lead to an increase of the local O3 concentration. An evaluation of the net health effects of such pollutant changes is therefore important ...to ascertain whether the emission control measures effectively improve the overall protection of public health. In this study, we use a short-term health risk (added health risk or AR) model developed for the multi-pollutant air quality health index (AQHI) in Hong Kong to examine the overall health impacts of these pollutant changes. We first investigate AR changes associated with NO2 and O3 changes, followed by those associated with changes in all four AQHI pollutants (NO2, O3, SO2, and particulate matter (PM)). Our results show that for the combined health effects of NO2 and O3 changes, there is a significant reduction in AR in urban areas with dense traffic, but no statistically significant changes in other less urbanized areas. The increase in estimated AR for higher O3 concentrations is offset by a decrease in the estimated AR for lower NO2 concentrations. In areas with dense traffic, the reduction in AR as a result of decreased NO2 is substantially larger than the increase in AR associated with increased O3. When additionally accounting for the change in ambient SO2 and PM, we found a statistically significant reduction in total AR everywhere in Hong Kong. Our results show that the emission control measures resulting in NO2, SO2, and PM reductions over the past decade have effectively reduced the AR over Hong Kong, even though these control measures may have partially contributed to an increase in O3 concentrations. Hence, efforts to reduce NOx, SO2, and PM should be continued.
Display omitted
•Health risk tradeoffs between decreased NO2 and increased O3 concentrations.•Lower NO2 concentrations offset short-term health risk for higher O3 concentrations.•Short-term health risk for the mixture of NO2 and O3 decreased at roadside stations.•Overall health risk related to four AQHI pollutants (NO2, O3, SO2 and PM) decreased.
Abstract
Background
Coronavirus disease 2019 (COVID-19) is a life-threatening respiratory condition caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was initially detected ...in China in December 2019. Currently, in Germany >140 000 cases of COVID-19 are confirmed. Here we report a nosocomial outbreak of SARS-CoV-2 infections in the pediatric dialysis unit of the University Hospital Münster (UHM).
Methods
Single-step real-time reverse-transcription polymerase chain reaction (rRT-PCR) from nasopharyngeal swabs was used to diagnose the index patient and identify infected contacts. Epidemiological links were analyzed by patient interviews and medical record reviews. In addition, each contact was assessed for exposure to the index case and monitored for clinical symptoms. Cycle threshold (Ct) values of all positive test results were compared between symptomatic and asymptomatic cases.
Results
Forty-eight cases were involved in this nosocomial outbreak. Nine contact cases developed laboratory-confirmed COVID-19 infections. Two SARS-CoV-2–positive cases remained clinically asymptomatic. Eleven cases reported flulike symptoms without positive results. Ct values were significantly lower in cases presenting typical COVID-19 symptoms, suggesting high viral shedding (P = .007).
Conclusions
Person-to-person transmission was at the heart of a hospital outbreak of SARS-CoV-2 between healthcare workers (HCWs) and patients in the pediatric dialysis unit at UHM. Semiquantitative rRT-PCR results suggest that individuals with high viral load pose a risk to spread SARS-CoV-2 in the hospital setting. Our epidemiological observation highlights the need to develop strategies to trace and monitor SARS-CoV-2–infected HCWs to prevent COVID-19 outbreaks in the hospital setting.
Forty-eight cases were involved in a nosocomial outbreak of SARS-CoV-2 infections in a pediatric dialysis unit due to person-to-person transmission. Our results outline strategies to trace and monitor SARS-CoV-2–infected healthcare workers including virology testing and infection control measures.
In response to the spread of COVID-19, China implemented a series of control measures. The causal effect of these control measures on air quality is an important consideration for extreme air ...pollution control in China. Here, we established a difference-in-differences model to quantitatively estimate the lockdown effect on air quality in the Beijing-Tianjin-Hebei (BTH) region. We found that the lockdown measures did have an obvious effect on air quality. The air quality index (AQI) was reduced by 15.2%, the concentration of NO2, PM10, PM2.5, and CO were reduced by 37.8%, 33.6%, 21.5%, and 20.4% respectively. At the same time, we further explored the heterogeneous effects of travel restrictions and the control measure intensity on air quality. We found that the traffic restrictions, especially the restriction of intra-city travel intensity (TI), exhibited a significant heterogeneous effect on NO2 with a decrease of approximately 13.6%, and every one-unit increase in control measures intensity reduced the concentration of air pollutants by approximately 2–4%. This study not only provides a natural, experimental basis for control measures on air quality but also indicates an important direction for future control strategies. Importantly, determining the estimated effect helps formulate accurate and effective intervention measures on the differentiated level of air pollution, especially on extreme air pollution.
This paper shows the impact of control measures on the predictive COVID-19 mathematical model in Rwanda through sensitivity analysis of the basic reproduction number R0. We have introduced different ...levels of the control measures in the model, precisely, 90%, 80%, 60%, 40%, 20%, 0% and studied their effects on the variation of the model variables. The results from numerical simulations reveal that the more the adherence to the control measures at the percentage of 90%, 80%, 60%, 40%, 20%, 0%, the more the number of COVID-19 cases, hospitalized and deaths reduces which indicates the reduction of the spread of the pandemic in Rwanda. Moreover, It was shown that the transition rate from the infectious compartment is very sensitive to R0 as the increase/decrease in its value increases/decreases the value of R0 and this leads to the high spread or the containment of the pandemic respectively.
•Mathematical model for Covid-19.•Basic reproduction number.•Covid-19 in Rwanda.•Impacts of control measures on Covid-19 mathematical model.•Sensitivity analysis.
In August 2016, continuous measurements of volatile organic compounds (VOCs) and trace gases were conducted at an urban site in Wuhan. Four high-ozone (O3) days and twenty-seven non-high-O3 days were ...identified according to the China's National Standard Level II (∼100 ppbv). The occurrence of high-O3 days was accompanied by tropical cyclones. Much higher concentrations of VOCs and carbon monoxide (CO) were observed on the high-O3 days (p < 0.01). Model simulations revealed that vehicle exhausts were the dominant sources of VOCs, contributing 45.4 ± 5.2% and 37.3 ± 2.9% during high-O3 and non-high-O3 days, respectively. Both vehicle exhausts and stationary combustion made significantly larger contributions to O3 production on high-O3 days (p < 0.01). Analysis using a chemical transport model found that local photochemical formation accounted for 74.7 ± 5.8% of the daytime O3, around twice the regional transport (32.2 ± 5.4%), while the nighttime O3 was mainly attributable to regional transport (59.1 ± 9.9%). The local O3 formation was generally limited by VOCs in urban Wuhan. To effectively control O3 pollution, the reduction ratio of VOCs to NOx concentrations should not be lower than 0.73, and the most efficient O3 abatement could be achieved by reducing VOCs from vehicle exhausts. This study contributes to the worldwide database of O3-VOC-NOx sensitivity research. Its findings will be helpful in formulating and implementing emission control strategies for dealing with O3 pollution in Wuhan.
Display omitted
•Vehicular emissions were the largest contributor to VOCs in Wuhan.•VOCs from vehicular exhausts made the highest contribution to O3 formation.•Regional transport accounted for ∼60% and ∼30% of nighttime and daytime O3, respectively.•The reduction ratio of VOCs to NOx concentrations should not be lower than 0.73 for effective O3 control.
Local formation dominated daytime O3, while nighttime O3 was attributable to regional transport in Wuhan.
PDF
