Indoor Environment and Viral Infections

A comprehensive review of microbial contamination in the indoor environment: sources, sampling, health risks, and mitigation strategies

The quality of the indoor environment significantly impacts human health and productivity, especially given the amount of time individuals spend indoors globally. While chemical pollutants have been a focus of indoor air quality research, microbial contaminants also have a significant bearing on indoor air quality. This review provides a comprehensive overview of microbial contamination in built environments, covering sources, sampling strategies, and analysis methods. Microbial contamination has various origins, including human occupants, pets, and the outdoor environment. Sampling strategies for indoor microbial contamination include air, surface, and dust sampling, and various analysis methods are used to assess microbial diversity and complexity in indoor environments. The review also discusses the health risks associated with microbial contaminants, including bacteria, fungi, and viruses, and their products in indoor air, highlighting the need for evidence-based studies that can relate to specific health conditions. The importance of indoor air quality is emphasized from the perspective of the COVID-19 pandemic. A section of the review highlights the knowledge gap related to microbiological burden in indoor environments in developing countries, using India as a representative example. Finally, potential mitigation strategies to improve microbiological indoor air quality are briefly reviewed.

Assessment of the Perception of Sustainability for Occupants of Residential Buildings: A Case Study in the UAE

The residential sector is multi-faceted by nature. Although evidence shows that the UAE is among the countries in the world that take sustainability seriously, there is a lack of information about the perception of sustainability by occupants in the residential sector in the UAE. The aim of this paper is to assess the perception of sustainability of the residential sector in the UAE, which is achieved by following a methodological framework using the relevant literature review and experts’ knowledge. An online survey was distributed to the targeted population, followed by a statistical analysis to fulfill the aim of the paper. Results confirm the correlation between social, economic, and environmental aspects of sustainability. Additionally, structural equation modeling reveals that the perception of sustainability is significantly influenced by economic and environmental aspects in the residential sector in the UAE. Comparative analysis shows a statistical difference in the perception of sustainability among gender, educational level, employment status, and monthly income. Finally, a predictive classification model is built to classify the perception of occupants based on their attributes using decision tree algorithms. The outcomes of this study would be beneficial to policy and decision makers, developers, contractors, designers, and facility management entities to enhance overall sustainability in the residential sector.

Assessment method for new sustainability indicators providing pandemic resilience for residential buildings

The method presented in this paper aims to support the sustainability assessment methods of residential buildings under pandemic conditions. The main purpose of the study is to review existing criteria of the well-known assessment tools and then to suggest a set of assessment measures for the emerging pandemic-resilient indicators. Current sustainability assessment methodologies mostly focus on the conventional sustainability pillars (Environmental, Social, Economic), whereas the proposed emerging sustainability assessment indicators include changes in sustainability requirements brought by the current pandemic. Firstly, a set of indicators with possible measures was identified; then, we reviewed several existing green building certification systems to identify their gaps and developed a foundation for each indicator. Finally, several round table discussions involving various stakeholders (e.g., engineers, designers, health care experts, academics) were conducted to consolidate the identified measures. The findings of the present study indicate that certain pandemic-resilient indicators are not fully addressed by existing assessment tools, pointing out the importance of the development of new measures to make them more suitable to use under pandemic conditions. Thus, the present study contributes to the building assessment methods by proposing a set of emerging assessment indicators with measures, which can be used by various professionals that would contribute to more sustainable buildings in upcoming pandemics.•A 5-point scale was used to assess the indicators, and various stakeholders in a previous study identified their weights.•The methodology introduces new pandemic-related indicators into the conventional sustainability concept.•The assessment measures are rapid and economically efficient to apply for any residential building.

Estimating aerosol transmission risk of SARS-CoV-2 in New York City public schools during reopening

The objective of this study was to estimate the risk of SARS-CoV-2 transmission among students and teachers in New York City public schools, the largest school system in the US. Classroom measurements conducted from December 2017 to September 2018 were used to estimate risk of SARS-CoV-2 transmission using a modified Wells-Riley equation under a steady-state conditions and varying exposure scenarios (infectious student versus teacher, susceptible student versus teacher, with and without masks). We then used multivariable linear regression with GEE to identify school and classroom factors that impact transmission risk. Overall, 101 classrooms in 19 schools were assessed, 86 during the heating season, 69 during cooling season, and 54 during both. The mean probability of transmission was generally low but varied by scenario (range: 0.0015-0.81). Transmission rates were higher during the heating season (beta=0.108, p=0.010), in schools in higher income neighborhoods (>80K versus 20K-40K beta=0.196, p<0.001) and newer buildings (<50 years beta=0.237, p=<0.001; 50-99 years beta=0.230, p=0.013 versus 100+ years) and lower in schools with mechanical ventilation (beta=0.141, p=0.057). Surprisingly, schools located in older buildings and lower-income neighborhoods had lower transmission probabilities, likely due to the greater outdoor airflow associated with an older, non-renovated buildings that allow air to leak in (i.e. drafty buildings). Despite the generally low risk of school-based transmission found in this study, with SARS-CoV-2 prevalence rising in New York City this risk will increase and additional mitigation steps should be implemented in schools now.

Readiness Assessment of Green Building Certification Systems for Residential Buildings during Pandemics

One of the consequences of COVID-19 pandemic is the momentum it has created for global changes affecting various aspects of daily lives. Among these, green building certification systems (GBCSs) should not be left behind as significant potential modifications may be required to ensure their versatility for residential buildings due to the new pandemic reality. The present study aims to evaluate the readiness of chosen GBCSs for a proper assessment of existing residential housing sustainability in a post-pandemic world. Based on a literature review of the state-of-the-art data sources and round table discussions, the present study proposes a particular set of sustainability indicators covering special sustainability requirements under pandemic conditions. Then, those indicators are used to evaluate the readiness of selected GBCSs (BREEAM, LEED, WELL, CASBEE) to meet new pandemic-resilient requirements based on their responses to the indicators. The assessment shows that none of the reviewed GBCSs are fully ready to cover all the proposed indicators. GBCSs have differing focuses on particular sustainability pillars, which also affected their responses to pandemic-resilient categories. For instance, WELL rating system successfully responded to the health and safety category, whereas LEED showed better preparedness in terms of environmental efficiency. BREEAM and CASBEE systems have a more evenly distributed attention to all three pandemic-resilient categories (Health & Safety, Environmental Resources Consumption, and Comfort) with an accent on the Comfort category. On a specific note, all GBCSs are insufficiently prepared for waste and wastewater management. In the future, GBCSs should be modified to better adapt to pandemic conditions, for which the current work may provide a basis. As an alternative, brand new standards can be created to face newly arising and evolving post-pandemic requirements.