Indoor Environmental Quality

In this paper the need for change of the present practice of building ventilation is discussed. Results on the importance of ventilation for the health of building occupants are presented to justify the need for change of the focus from room ventilation to ventilation for occupants. The present ventilation design based on ventilation rate has to be complimented with ventilation design based on ventilation air distribution. The performance of advanced ventilation methods providing optimal room air distribution is compared with the present mixing ventilation. The importance of proper design of advanced ventilation and its implementation and operation in practice is highlighted. The need for updating the present standards and considering new standards responding to the developed advanced ventilation methods is concluded.

Household Air Pollution (HAP) contributing from open fires or inefficient stoves fed by biomass, coal and kerosene are being used by 2.4 billion people across the world that has resulted in 3.2 million deaths per year. In the present study, Particulate Matter (PM₁₀ and PM_2.5) were investigated in biomass and LPG based households during summer and monsoon seasons, followed by evaluation of health risks for women in rural areas of Telangana state in India. Health impact and risk assessment of air pollution were estimated by WHO developed software tool called AIRQ+ . PM₁₀ and PM_2.5 concentrations in biomass households were ~1.8 and 2.7 times greater than those of LPG due to high emission factor of the biomass. Health risk assessment of women in biomass households exhibited high non-carcinogenic risk against LPG. The health impact assessment revealed high incidence per 100,000 population for an acute exposure of asthma, unhealthy days and lost workdays of 1009, 318 and 312, respectively. However, chronic exposure has resulted in stroke (77.23), ischemic heart disease (71.15), acute lower respiratory infections (51.93) and chronic obstructive pulmonary diseases (33.26). This study establishes the HAP contributing from fuel-type and evaluates health risks associated with the PM exposure.

Volatile organic compounds (VOCs) are effective finger-print compounds to apportion pollutants to their sources and also to detect certain diseases. Hence there is an increasing number of studies on the sensitive and selective detection of these compounds in the gas phase. In the present study, sampling and analysis for VOCs were carried out as per the USEPA Compendium Method TO-17 for 54 selected VOCs in industrial indoor environments. The samplers were allowed to run for 8 h at the blast hole drilling yard (BHD), conveyor belt yard (CB) and Belt re-conditioning plant (BRP) in an open-cast lignite mine. Results of chemical fingerprinting revealed that chloroform was present in higher concentrations in BHD and CB, whereas toluene was present in higher levels at BRP. Trichloroethylene (TCE) was only identified in BHD but not in the other two locations. Its presence in BHD is due to the chemicals or degreasing solvents utilized. The level of aliphatic VOCs was higher in BHD and CB, whereas, in the case of BRP aromatic VOCs level was higher. Naphthalene is one of the most volatile polyaromatic hydrocarbons, and it was only found in BRP. Rubber solution is commonly used in belt reconditioning, and this could be the source of naphthalene. The identified fingerprint compounds can be used for the forensic investigation of pollution from mining-related activities.

Exposure to indoor particulate matter (PM) plays a significant role in human respiratory problems resulting in multiple adverse health outcomes. PM having an aerodynamic diameter ≤10 µm, enters the human airways due to its smaller size and gets deposited in different parts of the human lungs. In the present communication, we measured real-time size segregated particulate matter mass concentrations in residential houses’ indoor environments in Pune's urban locations by Grimm aerosols spectrometer during the day hours (i.e.10 a.m–5 p.m.) in the month of July 2021. Average concentrations of indoor PM₁₀, PM_2.5, and PM₁ were found to be 60.7 ± 30.6, 37.3 ± 24.6, and 23.2 ± 19.7 µg m⁻³, respectively. Particle deposition in human airways diversely depends on the airway’s geometric structure. Thus, the evaluation of respiratory deposition doses (RDDs) in the head airway (HD), tracheobronchial (TB), and alveolar (AL) regions of PM (i.e., PM₁₀, PM_2.5, and PM₁) were estimated by using the human respiratory tract model (ICRP 1994) for different age groups like infants, children, adults, and elderly in residential premises. For the calculation of RDDs, tidal volume and breathing frequency of lungs for different age groups were considered. Total respiratory deposition of PM₁₀ was frequently higher than PM_2.5 and PM₁ over all age groups. However, among all, the elderly people experienced the highest total PM₁₀, PM_2.5, and PM₁ deposition (46 × 10^–2, 29 × 10^–2, and 9 × 10^–2 µg min⁻¹), followed by adults, children, and infants. Results derived from tracheal regional deposition exhibited the dominance of PM₁₀, PM_2.5, and PM₁ in HD, TB, and AL regions, respectively.

One of the major global causes of indisposition and impermanence, affecting both women and children in developing and under developed nations alike, is indoor air pollution. Exposure of children to PM_2.5 in metropolitan environments poses very serious health hazards. Compared to other air pollutants, fine particulate matter (PM_2.5) is known to pose substantial health risks. The goal of the current study is to quantify the levels of PM_2.5 in both the winter and summer months while also examining seasonal variation. Using Envirotech APM 550, sampling was carried out from November 2021 to June 2022. The sampler was positioned indoors in urban dwellings in the Indian city of Lucknow. A total of 24 homes were chosen. The study also evaluated climatic conditions and identified influences on the concentration of the particle pollution. According to the findings, winter time PM_2.5 concentrations were higher than summer time ones. The average indoor PM_2.5 concentration during the winter was discovered to be 228.62 ± 29.5 µg/m³, whereas the concentration during the summer was noted to be 137.18 ± 21.3 µg/m³. Health risks assessment (HRA) on children under the age of 18 ranged from 0.06 * 10^–6 in the winter to 0.026 * 10^–6 in the summer.

A Metro system, also known as a subway/rapid transit system (RTS), is a high-capacity urban transport facility. The present study investigated indoor air quality and passengers’ exposure to PM, TVOC, CO₂, and bacteria. Monitoring was conducted from Mar-Jun 2019. Four underground metro stations were selected. Data were collected for seven successive days in each station and inside trains. PM, TVOC, and bacteria concentrations were 2–5 folds the regulatory limits specified by WHO and EPA. In metro stations, the concentrations of PM₁₀ and PM_2.5 were in the range of 22.55 ± 3.21 to 74.23 ± 8.87 and 16.94 ± 1.89 to 49.39 ± 7.41 µg/m³, respectively. The concentrations of TVOC surpassed the regulatory limit in all stations with the range of 210 ± 41 to 614 ± 37 ppb. The maximum concentration of CO₂ was 567 ± 32 ppm. Further, the concentrations of bacteria were substantially high in all stations in the range of 1487 ± 951 to 2573 ± 691 CFU/m³. Moreover, the personal exposure of passengers to air pollutants was 5–9 folds in underground and 2–3 folds in aboveground stations than in-train exposure. Passenger activities and infiltration were significant contributors to elevated pollutant concentrations. The lower concentrations of CO₂ indicate a good amount of air circulation, while critical concentrations of other air pollutants indicate filthy air.

Healthy indoor environmental quality in the offices is a key factor for good health and productive work output. The ventilation facilities, construction materials and design of the buildings are the key factors to influence the indoor environmental quality, i.e., thermal comfort and pollutant concentrations. The present study attempted to evaluate the indoor environmental quality of a newly renovated office building in Naraina Industrial area using sensor based monitors. The study measured PM_2.5, relative humidity and temperature in different indoor micro-environments of the building including canteen area. The monitoring is carried out in indoor as well as outdoor environment using real time sensors based affordable monitor during one week period in September, 2022. The data analysis includes pollutant concentrations with and without operation of the ventilation system, indoor/outdoor ratio of pollutants, indoor air quality during working and non-working hours etc. The study also emphasized on the emission of pollutants due to cooking practices in the canteen area. The findings of the study highlight the effect of ventilation rate in the office building, office and canteen activities and infiltration of outdoor pollution.

The present study aimed to evaluate the relationship between physicochemical characteristics and toxicological assessment of indoor PM bound chemical and biological constituents. The average concentration of both indoor PM₁₀ and PM_2.5 exceeded the NAAQS standards of India. Metals of geogenic origin (Fe and Mn) are predominant in PM₁₀ samples, while the metals of anthropogenic origin (Ni, Co, Cd, Pb, Cu, Cr, and Zn) were dominant in PM_2.5. Among all analyszd metals, Fe exhibited the maximum concentrations in both sized PM followed by Mn, pb, Cr, Cu and Ni suggesting considerable health risk to the exposed inhabitants due to their ability to generate reactive oxygen species through Fenton’s reaction, mainly responsible for causing PM toxicity. Commonly isolated bacteria and fungi identified in the indoor environment were Bacillus sp., Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus sp. and Penicillium sp., respectively. Amongst them, Pseudomonas aeruginosa and Aspergillus sp. were found to be predominant in both sized PM revealing a significant health risk due to their association with various respiratory tract infections. The cytotoxic profile of indoor PM and their constituents determined by MTT assay on A549 cells exhibited a significant decrease in cell viability indicating the cytotoxic behavior of particles. Oxidative reactivity of indoor PM in terms of DTT assay showed considerable DTT depletion suggesting the oxidative nature of PM. Results of the present study will be effectual to raise awareness and address the better indoor air quality for the residents.

In recent year’s indoor air quality has gained much attention throughout the globe. It was ranked as the top five risks to public health. People spend most of their time indoors, it might be their home, workplace or while commuting. They are exposed to different micro environments without knowing that they are inhaling substantially high concentrations of different indoor air pollutants (IAPs). In developing countries, IAP concentrations are generally found high due to poor ventilation and numerous indoor sources. Poor IAQ can severely damage the mental, physical and social ability of a person, which can affect the working efficiency and result in loss in overall productivity. The present study focused on the determination of air exchange rate (AER), ventilation rate (VR) Q, and indoor air quality index (IAQI) for the community kitchen. The study was conducted for 3 days from 18-10-2022 to 20-10-2022. In this study, different pollutants like PM10, PM2.5, PM1, TVOCS, CO₂, CO, O₃, NO₂ were studied. Comfort parameters temperature and relative humidity were also monitored. The levels of all the pollutants, comfort parameters were shown higher on 20-10-22 when cooking activities like frying potato, frying fish took place have crossed the WHO guidelines 2009. The AER value varied from 0.9915 to 0.9906 h⁻¹. Lowest value was observed on the highly polluted day i.e. 20-10-2022. Similarly, the VR varied from 0.8262 to 0.8254 lit/s/m². This VR has shown that buildings have fallen to category III i.e. high polluting buildings according to ventilation rate for non-residential buildings (European Standard, EN 15,251). The indoor air quality index (IAQI) is calculated based on 5 criteria pollutants PM10, PM2.5, CO, O₃, NO₂ showed that the health condition of the workers falls into the very severe to poor category (NAQI 2014). Further the study suggests the measures to enhance IAQ that can be practiced in the community kitchen which were observed during the study.

Indoor Air Quality (IAQ) is now well recognized as impacting employee work efficiency. Poor indoor air quality can lead to productivity problems and absence from work. To examine IAQ conditions inside offices in an academic institute, IIT Kanpur, real-time monitoring of particulate matter (PM) was conducted during office hours (10 am to 5 pm). Particulate levels inside five offices on different floors of a multi-storeyed building were monitored over three consecutive days. All offices are on the same side of the building and have 3–6 permanent staff each. Office occupants were given a questionnaire survey to obtain feedback on health-related discomfort indoors (sleepiness, headache, and eye irritation). Only one location (Office A on the first floor) marginally met the current WHO guidelines for PM₁₀ (45 μg/m³), and all others far exceeded it. At least one-fifth of the staff in the four offices that do not meet the WHO guidelines complained about health-related discomfort. Mass (due to PM₁₀) retained in the trachea-bronchi (TB) of the lungs of office (these four) occupants (using the Multiple-Path Particle Dosimetry (MPPD) model) was 50% (average) higher than that in the case of staff in office A. The office with the highest number of printing appliances shows the highest concentration of fine-particulate matter (PM₁) and confirms the influence of indoor sources on IAQ. Air purifiers are low-cost interventions that can improve IAQ. Achieving the WHO guidelines inside offices will reduce particle mass retained on the TB up to a staggering 56%. Meeting guidelines may increase the efficiency of workers in these offices by 12–45%.

Ventilation rates significantly impact indoor thermal comfort and air quality. In this study, a week-long field measurement was conducted in a hostel room with natural ventilation on the academic campus of IIT-Kanpur, India. Indoor air temperature (T_a) and CO₂ concentration were monitored continuously in the single-occupant room during wintertime in January 2022. We evaluated the data for dynamic ventilation rates (VRs) and the relationship between air exchange rates (AERs) and thermal comfort inside the room. Considering CO₂ released by occupants as a tracer gas, the tracer gas decay method is applied to measure CO₂ concentrations for daytime and night-time decay episodes. The dynamic VRs vary from 1 to 19 L/s per person (AER—0.14–2.67 h⁻¹). The daytime VRs were approximately 45% higher than night-time. The predicted thermal conditions in the hostel room (using PPV/PMV model) were uncomfortable for approximately 22% of the total time, mainly during the night and early morning hours. A neutral temperature of 22.7 °C and a comfortable temperature range of 20.6–24.6 °C were determined (\({T}_{a}\) = 18.6–24.8 °C). The difference between AER_comfortable (0.14–2.67 h⁻¹) and AER_{uncomfortable} (0.31–2.66 h⁻¹) was not statistically significant (p > 0.05). This suggests that AER is not a prominent factor affecting thermal comfort during winter in the hostel. The high diurnal variation observed in VRs highlights the need for dynamic measurement that reflects the actual dynamic characteristics. Information obtained will help plan interventions and design toward achieving better thermal conditions in the hostel environment.

Daylight plays a crucial role in the educational environment which enables better performance, learning rates and has a significant impact on the visual comfort of the students for which the classroom designs must be carefully considered. In addition to promoting a state of calm contemplation, it also makes large energy savings feasible. Having access to daylight in the buildings is essential but it is critical to control the glare risk it poses. The main objective of this study is to assess the relationship between the daylight conditions in Architecture classrooms and student’s perception about it. This study also analyses the glare and its impact on visual comfort of students while performing various tasks in the design studios of Dr. Bhanuben Nanavati College of Architecture, Pune. Daylight simulation programme “Light Stanza”, Interviews, observations were used to gather the data. According to the survey results, the perception of visual comfort is mostly affected by orientation, distance from windows and varies with various tasks performed at the studios. Given that the intensity and length of light exposure throughout the day affect human health, the presence of glare thus directly correlates with the student's visual discomfort.

In this study, we discuss the benefits of “antimicrobial air filters” over “normal air filters” for protection against airborne pathogens and air pollutants developed in the laboratory of IISc Bangalore and IIT Kanpur. While normal air filters work on a capture mechanism to become a breeding ground for captured germs, antimicrobial air filters are coated with bio-polymers and polycationic polymers that can deactivate the germs. The formation of ROS (reactive oxygen species) i.e. H₂O₂ leads to the deactivation of germs. Polymers being used, in this study are a safe and sustainable alternative to heavy metal (Ag/Cu) doped coating that has proven toxic to humans. The antimicrobial filters are tested to deactivate micro-organisms, such as Escherichia Coli, Staphylococcus Aureus, Influenza, MS2 Bacteriophage, Aspergillus brasiliensis, and SARS-CoV-2 (delta variant). It was also proven that normal filters have a negative reduction which implies the growth of microorganisms. Structural and filtration integrity of anti-microbial air filters were upheld without affecting the filter's porosity and initial pressure drop. There was no statistically significant difference in pressure drop and filtration efficiency observed between coated and uncoated filters. Furthermore, the coated air filters maintained antimicrobial activity throughout the operational lifetime with regenerative ROS formation. Antimicrobial air filters pave the way for better protection against infection spread and air pollutants. It prevents the air filter to become a breeding ground for germs using bio-polymers that are biodegradable and non-toxic.