IMPACT of COVID-19 PANDEMIC on AIR QUALITY in A TOURISTIC REGION

The rise of the COVID-19 pandemic led governments to impose mobility restrictions to their citizens and companies, having a greater impact on tourism. This can be used as a global-scale opportunity to study the impact of those restrictions on air quality, particularly in tourist sites. Hence, the aim of this work was to evaluate the impact of the COVID-19 pandemic on air quality in a touristic region. Air pollution was evaluated in a prominent touristic region in southern Europe (Algarve, Portugal). The concentrations of PM10, NO2, O3 and CO were obtained from four air quality monitoring stations (traffic and background) in two lockdown and two lifting periods. The data collected was compared with historical data (20152019) and with reference limit values in the Portuguese legislation and the World Health Organization (WHO) guidelines. Overall, PM10 reduced in all studied periods and stations, with a higher decrease during the 1st lockdown and lifting (5.30%73.6%) compared to the 2nd periods in the urban traffic and background stations, as well as NO2 (35.8%56.5%), in the urban background station evaluated. O3 diminished in general (until 29.1%), while CO decreased during the 1st lockdown and lifting periods (64.5%80.7%) and increased in the subsequent periods (9.66%65.1%) in the urban traffic station. The percentage of exceedances to the reference limit values both in the legislation and in WHO guidelines mainly decreased or remained equal in all the studied periods when compared with the previous years. Thus, it was concluded that the mobility restrictions imposed during the COVID-19 pandemic contributed to a general reduction of air pollution in tourist sites. Since tourism is an important economic activity, some specific policies were proposed based on those restrictions, considering a sustainable equilibrium between the economy, the environment, and human health. (c) 2021 WIT Press

Impact of COVID-19 Pandemic on Air Quality: A Systematic Review

With the emergence of the COVID-19 pandemic, several governments imposed severe restrictions on socio-economic activities, putting most of the world population into a general lockdown in March 2020. Although scattered, studies on this topic worldwide have rapidly emerged in the literature. Hence, this systematic review aimed to identify and discuss the scientifically validated literature that evaluated the impact of the COVID-19 pandemic and associated restrictions on air quality. Thus, a total of 114 studies that quantified the impact of the COVID-19 pandemic on air quality through monitoring were selected from three databases. The most evaluated countries were India and China; all the studies intended to evaluate the impact of the pandemic on air quality, mainly concerning PM10, PM2.5, NO2, O-3, CO, and SO2. Most of them focused on the 1st lockdown, comparing with the pre- and post-lockdown periods and usually in urban areas. Many studies conducted a descriptive analysis, while others complemented it with more advanced statistical analysis. Although using different methodologies, some studies reported a temporary air quality improvement during the lockdown. More studies are still needed, comparing different lockdown and lifting periods and, in other areas, for a definition of better-targeted policies to reduce air pollution

Sustainable policies for air pollution reduction after COVID-19 pandemic: Lessons learnt from the impact of the different lockdown periods on air quality

Due to the COVID-19 pandemic, governments imposed several mobility restrictions which can be used to evaluate their impact on air quality and generate better-targeted policies to improve it. Therefore, this study aimed to define sustainable mitigation measures to reduce air pollution based on quantifying the impacts of the restrictions imposed during the COVID-19 pandemic on air quality in Portugal. Thus, hourly concentrations of PM10, PM2.5, NO2, O-3, CO and SO2 were obtained from the Portuguese Air Quality Monitoring Network. Data was then divided into six periods (2020-2021) and compared with the corresponding historical periods (2015-2019). Furthermore, the satellite data of NO2, CO, and absorbing aerosol index (AAI) from the sentinel-5P TROPOMI was collected to complement the analysis conducted for the monitoring data. Overall, air quality improved in all study periods and areas, except in industrial sites. The satellite data corroborated the results herein achieved and thus validated the real effect of the measures adopted in the country during the pandemic on air quality. Sustainable policies to improve air quality could include remote (or hybrid) work whenever possible as a long-term measure and prohibition of travelling between municipalities when an extraordinary event of high air pollution is predicted or occurs. Other policies should be adopted for industrial areas. Given this, and as the restrictive mobility measures had a strong effect on reducing air pollution, the post-COVID era represents an opportunity for society to rethink future mobility and other emerging policies, that should favour softer and cleaner means of transportation

Marginal Bone Loss and Pink Esthetic Evaluation of Narrow-Diameter Dental Implants for Single Crowns: 1-Year Prospective Clinical Study

Purpose: The aims of this study were: (1) to quantify the marginal bone loss (MBL) of 3.3-mm narrow-diameter, bone-level, titanium-zirconia (Ti-Zr) implants with two different surfaces in single restorations after a 1-year follow-up; (2) to analyze the combinations of different variables that may influence MBL; and (3) to record the Pink Esthetic Score (PES) value and its correlation with MBL. Materials and Methods: This is a prospective longitudinal clinical study with a 1-year follow-up after crown placement. Two different implant surfaces (sandblasted acid-etched and modified sandblasted acid-etched) were used. All bone-level and bone level-tapered implants had a diameter of 3.3 mm. Different healing and prosthetic abutments were used. Clinical, radiographic, and photographic records were taken 6 months and 1 year after placement of the restorations, and the survival rate, MBL, PES, clinical parameters, and biologic and/or mechanical complications were assessed. The correlations between the variables and MBL were verified. Results: A total of 30 narrow-diameter implants were placed in 30 patients; 18 implants had a sandblasted acid-etched surface, and 12 implants had a modified sandblasted acid-etched surface. The measured MBL at 1 year after implant function had a mean value of-0.36 mm, ranging from 0 mm to-1.77 mm. There was no implant loss. A statistically significant relationship was observed between implant shape (design and length), implant placement level, healing abutment, prosthetic abutment size, gingival thickness, and MBL. The mean PES values recorded at the beginning and end of the study were 7.58 and 11.37, respectively. Conclusion: Narrow-diameter implants showed reduced MBL values, with the surrounding tissues remaining stable after 1 year of follow-up. The MBL did not show different values on two implant surfaces. MBL does not seem to influence esthetic outcome. Int.Oral Maxillofaciallmplants2022;37::515-524. doi: 10.11607/jomi.905

SARS-CoV-2 air sampling: A systematic review on the methodologies for detection and infectivity

This systematic review aims to present an overview of the current aerosol sampling methods (and equipment) being used to investigate the presence of SARS-CoV-2 in the air, along with the main parameters reported in the studies that are essential to analyze the advantages and disadvantages of each method and perspectives for future research regarding this mode of transmission. A systematic literature review was performed on PubMed/MEDLINE, Web of Science, and Scopus to assess the current air sampling methodologies being applied to SARS-CoV-2. Most of the studies took place in indoor environments and healthcare settings and included air and environmental sampling. The collection mechanisms used were impinger, cyclone, impactor, filters, water-based condensation, and passive sampling. Most of the reviewed studies used RT-PCR to test the presence of SARS-CoV-2 RNA in the collected samples. SARS-CoV-2 RNA was detected with all collection mechanisms. From the studies detecting the presence of SARS-CoV-2 RNA, fourteen assessed infectivity. Five studies detected viable viruses using impactor, water-based condensation, and cyclone collection mechanisms. There is a need for a standardized protocol for sampling SARS-CoV-2 in air, which should also account for other influencing parameters, including air exchange ratio in the room sampled, relative humidity, temperature, and lighting conditions.This work was financially supported by: LA/P/0045/2020 (ALiCE) and UIDB/00511/2020–UIDP/00511/2020 (LEPABE) funded by national funds through FCT/MCTES (PIDDAC); Project PTDC/EAM-AMB/32391/2017, funded by FEDER funds through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES. Priscilla G. Silva thanks the Portuguese Foundation for Science and Technology – FCT for the financial support of her PhD work (2020.07806.BD, CRM: 0026504) contract through the DOCTORATES 4 COVID-19 program. Sofia I.V. Sousa thanks the Portuguese Foundation for Science and Technology (FCT) for the financial support of her work contract through the Scientific Employment Stimulus—Individual Call—CEECIND/02477/2017

Radon in Indoor Air: Towards Continuous Monitoring

Radon poses significant health risks. Thus, the continuous monitoring of radon concentrations in buildings' indoor air is relevant, particularly in schools. Low-cost sensors devices are emerging as promising technologies, although their reliability is still unknown. Therefore, this is the first study aiming to evaluate the performance of low-cost sensors devices for short-term continuous radon monitoring in the indoor air of nursery and primary school buildings. Five classrooms of different age groups (infants, pre-schoolers and primary school children) were selected from one nursery and one primary school in Porto (Portugal). Radon indoor concentrations were continuously monitored using one reference instrument (Radim 5B) and three commercially available low-cost sensors devices (Airthings Wave and RandonEye: RD200 and RD200P2) for short-term sampling (2-4 consecutive days) in each studied classroom. Radon concentrations were in accordance with the typical profiles found in other studies (higher on weekends and non-occupancy periods than on occupancy). Both RadonEye low-cost sensors devices presented similar profiles with Radim 5B and good performance indices (R-2 reaching 0.961), while the Airthings Wave behavior was quite different. These results seem to indicate that the RadonEye low-cost sensors devices studied can be used in short-term radon monitoring, being promising tools for actively reducing indoor radon concentrations

Development of low-cost indoor air quality monitoring devices: Recent advancements

The use of low-cost sensor technology to monitor air pollution has made remarkable strides in the last decade. The development of low-cost devices to monitor air quality in indoor environments can be used to understand the behaviour of indoor air pollutants and potentially impact on the reduction of related health impacts. These user-friendly devices are portable, require low-maintenance, and can enable near real-time, continuous monitoring. They can also contribute to citizen science projects and community-driven science. However, low-cost sensors have often been associated with design compromises that hamper data reliability. Moreover, with the rapidly increasing number of studies, projects, and grey literature based on low-cost sensors, information got scattered. Intending to identify and review scientifically validated literature on this topic, this study critically summarizes the recent research pertinent to the development of indoor air quality monitoring devices using low-cost sensors. The method employed for this review was a thorough search of three scientific databases, namely: ScienceDirect, IEEE, and Scopus. A total of 891 titles published since 2012 were found and scanned for relevance. Finally, 41 research articles consisting of 35 unique device development projects were reviewed with a particular emphasis on device development: calibration and performance of sensors, the processor used, data storage and communication, and the availability of real-time remote access of sensor data. The most prominent finding of the study showed a lack of studies consisting of sensor performance as only 16 out of 35 projects performed calibration/validation of sensors. An even fewer number of studies conducted these tests with a reference instrument. Hence, a need for more studies with calibration, credible validation, and standardization of sensor performance and assessment is recommended for subsequent research

Can data reliability of low-cost sensor devices for indoor air particulate matter monitoring be improved?-An approach using machine learning

Poor indoor air quality has adverse health impacts. Children are considered a risk group, and they spend a significant time indoors at home and in schools. Air quality monitoring has traditionally been limited due to the cost and size of the monitoring stations. Recent advancements in low-cost sensors technology allow for economical, scalable and real-time monitoring, which is especially helpful in monitoring air quality in indoor environments, as they are prone to sudden peaks in pollutant concentrations. However, data reliability is still a considerable challenge to overcome in low-cost sensors technology. Thus, following a monitoring campaign in a nursery and primary school in Porto urban area, the present study analyzed the performance of three commercially available low-cost IoT devices for indoor air quality monitoring in real-world against a research-grade device used as a reference and developed regression models to improve their reliability. This paper also presents the developed on-field calibration models via machine learning technique using multiple linear regression, support vector regression, and gradient boosting regression algorithms and focuses on particulate matter (PM1, PM2.5, PM10) data collected by the devices. The performance evaluation results showed poor detection of particulates in classrooms by the low-cost devices compared to the reference. The on-field calibration algorithms showed a considerable improvement in all three devices' accuracy (reaching up to R2 > 0.9) for the light scattering technology based particulate matter sensors. The results also show the different performance of low-cost devices in the lunchroom compared to the classrooms of the same school building, indicating the need for calibration in different microenvironments

INDOOR VOC CONCENTRATIONS at NURSERY and PRIMARY SCHOOLS: IMPACT of COVID-19 PREVENTIVE MEASURES

The importance of evaluating indoor air pollutants, such as volatile organic compounds (VOC), became a topic of utmost interest, especially during COVID-19 pandemic due to the increasing cleaning and disinfection of hands, surfaces and spaces, the most common measures to prevent the spread of COVID-19. VOC presence in indoor environments can impair human health, particularly above threshold limit values. Thus, this study aimed to quantify the differences between VOC concentrations before and during COVID-19 pandemic in indoor air of one nursery and one primary school in Porto, Portugal. This study was carried out in early 2020 (before COVID-19 pandemic) and early 2021 (during COVID-19 pandemic) in two classrooms I07_A (nursery school) and S07_B (primary school). Both classrooms presented a similar school timetable between the two periods, but the personal and environmental hygiene throughout the day using alcohol-based sanitisers were hugely increased in 2021. Total VOC (TVOC) were monitored continuously with research-grade instruments for a minimum period of two consecutive weekdays. Two average periods were considered: (i) an average day period (hourly means of all weekdays); and (ii) an average occupancy period (hourly means during occupancy periods considering the school timetable). Descriptive statistical analysis, as well as normality (ShapiroWilk Test) and significance (Wilcoxon Signed Rank Test) tests were performed using the R software version 4.0.5. The statistical significance level considered was set to 0.05. TVOC concentrations exceeded the limit value in the Portuguese legislation (1,200 µg/m3) during occupancy period in both classrooms during COVID-19 pandemic, although they never exceeded before the pandemic. Moreover, a statistically significant increase (p-value < 0.05) on TVOC concentrations from 2020 to 2021 were observed in the two studied classrooms for both average day (mean difference: 647 µg/m3 and 1,170 µg/m3 for I07_A and S07_B, respectively) and average occupancy periods (mean difference: 521 µg/m3 and 2,730 µg/m3 for I07_A and S07_B, respectively). Therefore, it was possible to conclude that the continued use of alcohol-based products, as a result of COVID-19 prevention measures, could increase TVOC concentrations to unsafe levels in schools. (c) 2021 WIT Press

Impact of indoor air pollution in nursery and primary schools on childhood asthma

Poor indoor air quality in scholar environments have been frequently reported, but its impact on respiratory health in schoolchildren has not been sufficiently explored. Thus, this study aimed to evaluate the associations between children's exposure to indoor air pollution (IAP) in nursery and primary schools and childhood asthma. Multivariate models (independent and multipollutant) quantified the associations of children's exposure with asthma-related health outcomes: reported active wheezing, reported and diagnosed asthma, and lung function (reduced FEV1/FVC and reduced FEV1). A microenvironmental modelling approach estimated individual inhaled exposure to major indoor air pollutants (CO2, CO, formaldehyde, NO2, O-3, TVOC, PM2.5 and PM10) in nursery and primary schools from both urban and rural sites in northern Portugal. Questionnaires and medical tests (spirometry pre- and post-bronchodilator) were used to obtain information on health outcomes and to diagnose asthma following the newest international clinical guidelines. After testing children for aeroallergen sensitisation, multinornial models estimated the effect of exposure to particulate matter on asthma in sensitised individuals. The study population were 1530 children attending nursery and primary schools, respectively 648 pre-schoolers (3-5 years old) and 882 primary school children (6-10 years old). This study found no evidence of a significant association between IAP in nursery and primary schools and the prevalence of childhood asthma. However, reported active wheezing was associated with higher NO2, and reduced FEV1 was associated with higher O-3 and PM2.5, despite NO2 and O-3 in schools were always below the 200 mu g m(-3) threshold from WHO and National legislation, respectively. Moreover, sensitised children to common aeroallergens were more likely to have asthma during childhood when exposed to particulate matter in schools. These findings support the urgent need for mitigation measures to reduce IAP in schools, reducing its burden to children's health