Experimental and numerical evaluation of a new visor concept with aerodynamic sealing to protect medical professionals from contaminated droplets and aerosols.

The fast spreading of the SARS-CoV-2 virus led to a significant increase in the demand for personal protective equipment (PPE). Healthcare professionals, mainly dentists, work near the patients, increasing their risk of infection. This paper investigates the effectiveness of an air-curtain sealing effect in a newly designed visor developed to reduce the risk of contracting a respiratory infection. This PPE was developed by computational fluid dynamics (CFD) modeling. CFD results show that the aerodynamic sealing in this PPE device effectively protects the user's face by 43% from a contaminated environment. The experiments considered two different tests: one using a tracer gas (CO2 ) to simulate a gaseous contaminant inside and outside the PPE face shield and a second test using smoke to simulate aerosol transport and evaluate the PPE efficiency. The particle concentration within the aerodynamically sealed PPE was evaluated and compared with the protection efficiency of other PPE. Results show similar protection levels for particles in the 1-5 µm range between the prototype and a KN95 respirator. The combined use of this novel PPE with aerodynamic sealing and a physical mask (KN95 or surgical) produced protection efficiency values within the range of 57%-70% for particles greater than 0.5 µm. This study reveals the potential of using an air curtain combined with a face shield to reduce the risks from contaminated environments.

Effects of air pollution on health: A mapping review of systematic reviews and meta-analyses.

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.

Data of temperature and relative humidity in a historic library in Portugal.

The correct preservation of old and rare books in libraries needs suitable values of temperature and relative humidity. This paper shows the hygrothermal data acquired in a historic library, the Baroque Library, of the University of Coimbra, Portugal, where several old and rare books are stored. The data were acquired during a 6-month monitoring campaign. In particular, in this paper the spatial and temporal variations of these two parameters are analysed. The data presented in the article are related to the research article entitled "A procedure for identifying chemical and biological risks for books in historic libraries based on microclimate analysis" [1].

Indoor air quality audit implementation in a hotel building in Portugal.

Hotels are designed to provide high levels of comfort for guests; however, frequent complaints related to uncomfortable thermal environment and inadequate indoor air quality (IAQ) appear. On the other hand, there is little research concerning IAQ audits of hotels up to now. This study is aimed to establish and demonstrate the comprehensive IAQ audit approach for hotel buildings, based on Portugal national laws. A 4-star hotel building in Portugal is used as a case study to demonstrate the IAQ audit application and evaluate its comprehensiveness and usefulness to the hotel or facility managers. The systematic approach involves the measurement of physical parameters - temperature (dry bulb), relative humidity and the concentration of the suspended particulate matter (PM10) - the monitoring of the concentrations of selected chemical indicators - carbon dioxide (CO2), carbon monoxide (CO), formaldehyde (HCHO) and total volatile organic compounds (TVOCs) - and the measurements of biological indicators (bacteria, fungi, Legionella). In the present case, air exchange rates are measured by the concentration-decay method using metabolic CO2 as the tracer gas. The comprehensive IAQ audit revealed four main problems in the hotel building: (1) insufficient ventilation rate; (2) too high particle concentration in some rooms; (3) contamination by Legionella of the sanitary hot-water circuit; (4) poor filtration effectiveness in all air handling units (AHUs).