TVOC Concentrations Research Articles

Monitoring of indoor environmental quality and acoustic comfort in university classrooms

Indoor Environmental Quality (IEQ) in university classrooms affects students' well-being, comfort and learning performance, thus its evaluation is strongly needed. This work presents an in-field study on the acoustic monitoring, along with thermal, visual and air quality domains, in four recently built university classrooms of Politecnico di Torino. The monitoring was performed in the spring/summer and winter periods, through wall mounted multi-sensor devices. While the monitoring was ongoing, students attending lessons were asked to answer an online anonymous questionnaire on comfort perception, which included questions regarding the four domains and additional personal information. Results show that students are more satisfied with the overall conditions in classroom 3P and more dissatisfied with the overall conditions in classroom 4P. The less satisfying domains are the thermal and air quality ones, whereas the more satisfying are the acoustic and visual ones. Furthermore, at the increasing of TVOC and CO2 concentrations the overall satisfaction decreases. The final aim of this project, based on the monitoring results, is the optimization of the building systems management to reduce energy consumptions and ensure occupants' well-being and comfort.

A novel dataset of indoor environmental conditions in work-from-home settings

During the last week of March 2020, millions of workers around the world transitioned to working from home due to the COVID-19 pandemic. While much research has explored the behavioural and psychological aspects of work-from-home (WFH), few studies have provided data-driven evaluations of indoor environmental quality (IEQ). This paper presents findings from a summer 2022 field study of IEQ conditions in WFH settings, involving 95 participants in the North American Pacific Northwest. Sensors installed on participants' work desks continuously measured total volatile organic compounds (tVOC), particulate matter (PM2.5), carbon dioxide (CO2) air temperature, humidity, and sound pressure levels (SPLs). Participants also completed surveys on home and workspace characteristics, as well as their subjective assessments of IEQ, well-being, and productivity. The study found that mean indoor concentrations of tVOC, PM2.5, and CO2 were 262 ppb, 5 µg/m3, and 712 ppm, respectively. Indoor air temperature ranged between 14.7–32.3°C, with a mean of 22.8°C, while relative humidity and SPL averaged at 52.5% and 53.7 dBA. Statistically-significant associations were observed between IEQ variables and factors such as residence type, cooking habits, workspace type, and window availability. A future paper will assess the surveyed behavioural and psychological characteristics in greater detail.

Characteristics, Sources Analysis, and Environmental Impacts of VOCs Based on Photochemical Loss in Summer in Zhengzhou

To clarify the pollution characteristics and sources of atmospheric VOCs in Zhengzhou City in the summer, multi-site offline sampling and laboratory analyses of atmospheric VOCs in Zhengzhou were carried out in August 2022. The observed and initial VOC volume fraction levels, OFP, SOAFP, and sources were compared. During the study period, the average values of three-site observation and initial φ（VOCs） during the study period were （31.83 ±13.51）×10-9 and （35.92 ±15.30）×10-9,respectively. Olefins （52.5 %） and aromatic hydrocarbons （29.7 %） were the components with a higher photochemical loss rate, and the spatial variations of the observed TVOCs concentration at each site were： Zhengzhou University （ZZU） > Gangli Reservoir （GLR） > Jingkaiqu （JKQ）, and the concentrations of alkanes and OVOCs at each site were higher. Olefins and aromatic hydrocarbons were the components that contributed greatly to the formation of O3 and SOA. Motor vehicle sources, solvent-use sources, and industrial sources were the main contributing sources of atmospheric VOCs in Zhengzhou. Compared with the source analysis results based on the initial concentration, the contribution rates of motor vehicle sources, industrial sources, and solvent use sources were relatively high, and the contribution rates of combustion sources, plant sources, and oil and gas volatilization sources were relatively low.

Evaluation of CO2 and TVOC concentration in a school in Palma during the month of June

ABSTRACT In the context of a warmer climate, one of the population sectors most affected are children. Therefore, it is important to consider the study of school buildings since children invest there about 30% of their time. In schools, human activities (CO2) are the main sources of pollution, along with the emissions of construction materials and cleaning products (TVOC). Additionally, reaching good indoor air quality should not be to the detriment of adequate thermal comfort. This work aims to make a comparison between different classrooms of a school in Palma (Mallorca, Spain) by assessing the values of relative humidity, temperature, TVOC and CO2 concentration during the month of June, the warmest month. This study aims to contribute to the field with the achieved outcomes. It is observed that CO2 increases until it exceeds the limit levels, established by current policies, up to 54% of the time during school time. TVOC concentration also exceeds the limit, up to 65% of the time. On the other hand, indoor temperature is above the comfort range between 75 and 100% of the time, being higher than the outdoor temperature. The relative humidity is mainly within comfortable values.

Indoor Microclimatic Conditions and Air Pollutant Concentrations in the Archaeological Museum of Abdera, Greece

Indoor microclimate conditions and air pollutant concentrations (O3, TVOC, CO, CO2, and particulate matter mass concentrations in six size bins) were measured in the Greek Archaeological Museum of Abdera, which houses priceless works of art from the birthplace of the ancient philosopher Democritus. The monitoring campaign took place during the spring and summer months, when there were the greatest number of visitors. In the exhibition rooms, daily variations in relative humidity ranged from 4% to 10%, and daily variations in air temperature ranged from 0.9 °C to 2.6 °C. These uncontrolled changes may endanger the housed antiquities. The microclimate in the storage rooms varied substantially less than in the exhibition halls due to dehumidifiers and the lack of visitors. Concerning air pollution, indoor O3 concentrations were higher than the recommended limit values for the conservation of artwork. Even more worrisome are particulate matter mass concentrations above the air quality guidelines. Despite the fact that the building is well insulated and that only artificial lighting is used in the exhibition halls, it is difficult to achieve adequate conditions for the protection of the works of art.

Enhanced VOC emission with increased temperature contributes to the shift of O3-precursors relationship and optimal control strategy

Assessing the impact of anthropogenic volatile organic compounds (VOCs) on ozone (O3) formation is vital for the management of emission reduction and pollution control. Continuous measurement of O3 and the major precursors was conducted in a typical light industrial city in the YRD region from 1 May to 25 July in 2021. Alkanes were the most abundant VOC group, contributing to 55.0% of TVOCs concentration (56.43 ± 21.10 ppb). OVOCs, aromatics, halides, alkenes, and alkynes contributed 18.7%, 9.6%, 9.3%, 5.2% and 1.9%, respectively. The observational site shifted from a typical VOC control regime to a mixed regime from May to July, which can be explained by the significant increase of ROx production, resulting in the transition of environment from NOx saturation to radical saturation with respect to O3 production. The optimal O3 control strategy should be dynamically changed depending on the transition of control regime. Under NOx saturation condition, minimizing the proportion of NOx in reduction could lead to better achievement of O3 alleviation. Under mixed control regime, the cut percentage gets the top priority for the effectiveness of O3 control. Five VOCs sources were identified: temperature dependent source (28.1%), vehicular exhausts (19.9%), petrochemical industries (7.2%), solvent & gasoline usage (32.3%) and manufacturing industries (12.6%). The increase of temperature and radiation would enhance the evaporation related VOC emissions, resulting in the increase of VOC concentration and the change of ROx circulation. Our results highlight determination of the optimal control strategies for O3 pollution in a typical YRD industrial city.

Characterization and source apportionment of volatile organic compounds in Hong Kong: A 5-year study for three different archetypical sites

Initial success has been achieved in Hong Kong in controlling primary air pollutants, but ambient ozone levels kept increasing during the past three decades. Volatile organic compounds (VOCs) are important for mitigating ozone pollution as its major precursors. This study analyzed VOC characteristics of roadside, suburban, and rural sites in Hong Kong to investigate their compositions, concentrations, and source contributions. Here we show that the TVOC concentrations were 23.05 ± 13.24, 12.68 ± 15.36, and 5.16 ± 5.48 ppbv for roadside, suburban, and rural sites between May 2015 to June 2019, respectively. By using Positive Matrix Factorization (PMF) model, six sources were identified at the roadside site over five years: Liquefied petroleum gas (LPG) usage (33%–46%), gasoline evaporation (8%–31%), aged air mass (11%–28%), gasoline exhaust (5%–16%), diesel exhaust (2%–16%) and fuel filling (75–9%). Similarly, six sources were distinguished at the suburban site, including LPG usage (30%–33%), solvent usage (20%–26%), diesel exhaust (14%–26%), gasoline evaporation (8%–16%), aged air mass (4%–11%), and biogenic emissions (2%–5%). At the rural site, four sources were identified, including aged air mass (33%–51%), solvent usage (25%–30%), vehicular emissions (11%–28%), and biogenic emissions (6%–12%). The analysis further revealed that fuel filling and LPG usage were the primary contributors to OFP and OH reactivity at the roadside site, while solvent usage and biogenic emissions accounted for almost half of OFP and OH reactivity at the suburban and rural sites, respectively. These findings highlight the importance of identifying and characterizing VOC sources at different sites to help policymakers develop targeted measures for pollution mitigation in specific areas.

Using artificial neural networks to predict indoor particulate matter and TVOC concentration in an office building: Model selection and method development

Indoor particulate matter and TVOC pose a significant threat to the health of staff working in office buildings. The accurate prediction of indoor particulate matter and TVOC concentrations is crucial for the automatic operation of ventilation and filtration system to control these indoor pollutants. Artificial neural networks have the advantages of high accuracy, real-time monitoring, and multi-source data integrations. Their performances in predicting particulate matter and TVOC concentrations in office buildings need to be further studied. In this study, on-site sampling was conducted in a typical office building at northern China. A standardized database of indoor parameters for four different offices was created with a total of 6072 datasets for each parameter. Three artificial neural network models were used in this study: the back propagation neural network (BP-ANN), the multi-layer neural network (MLNN), as well as the long-term and short-term memory neural network (LSTM). Among these three models, the performance of the MLNN model was the best in predicting PM2.5 and PM10 concentrations. It achieved a FB ranging from -0.02 to -0.01, an NMSE ranging from 0.46 to 0.49 μg/m3, and an R2 between 0.78 and 0.81. The MLNN model and the random forest (RF) classification method were further used to predict indoor TVOC concentrations. The RF model achieved a relatively better performance with a prediction accuracy of 89.2 %. In addition, the models’ generalization abilities were further evaluated by using some smaller datasets. For the MLNN model, when predicting indoor PM2.5 concentration, as the amount of training data decreased from 80 % to 20 %, its FB decreased from 0.41 to 0.03, its NMSE changed from 1.53 μg/m3 to 0.53 μg/m3, and its R2 decreased from 0.69 to 0.07. The results in this study can contribute to the use of artificial intelligence algorithm in office buildings aiming at indoor pollutants control.

Physio-chemical analysis of pollutants in residential micro-environment through continuous monitoring and settled dust characterization

The concern about indoor air quality in various micro-environments has been on the rise as buildings are vulnerable to an array of contaminants generated from various sources. The study aims to investigate and highlight the pollutant sources and composition in middle-income residential spaces through a case study approach. With large migration from small towns and saturation of megacities, the middle-income population in tier-2 cities in India is on the rise, raising concern about the well-being of the dense urban population. It involves a careful selection of typical MIG housing to identify major pollution sources from outdoor and indoor environments. The focus lies in the findings stemming from continuous air quality monitoring of PM10, PM2.5, SO2, NO2, HCHO, TVOC, CO and C6H6 and an in-depth physio-chemical analysis facilitated by Fourier transform infrared (FTIR), Analytical Scanning Electron Microscope (A-SEM) and energy-dispersive X-ray (EDX) spectroscopy of settled household dust. Analysis unveiled indoor PM2.5 concentrations of 21.93 µg/m3, exceeding WHO standards, whereas, TVOC concentrations were higher indoors than outdoors. Stark disparities between indoor and outdoor dust compositions and sources were also observed. Despite limitations, it provides a portrait of middle-income housing conditions, offering insights for interventions and future research on indoor air quality challenges.

Study on indoor air quality of a newly built student dormitory in a university in Shenyang

During the heating season, a questionnaire survey was conducted among the test-occupancy staff of a newly built dormitory in a university in Shenyang, Liaoning Province, and the indoor air environment parameters of four dormitories were continuously monitored for 24h. The results show that the test residents have low satisfaction with the indoor air environment. The measured results show that the temperature of the four dormitories with high indoor air temperature ranges from 25.8 ℃ to 29.3℃, indoor air humidity meets the standard requirements, indoor CO2 and PM2.5 concentrations exceed the standard seriously, and HCHO and TVOC concentrations exceed the standard for a small amount of time.

Characteristics of air pollution complex in a typical chemical industrial development zone in eastern China

VOCs (volatile organic compounds) have an important impact on the atmospheric environment, climate and human health. In a typical chemical industrial development zone in eastern China, 123 kinds of VOCs were on-line monitored simultaneously at three sites using the GC-FID/MS system for one year. The seasonal and diurnal variations of composition and concentration of VOCs were compared and analyzed systematically. The VOCs features existed significant differences at the three sites, which were greatly affected by the types and emissions of surrounding enterprises. The alkanes appeared as the major pollutants at the site adjacent to petrochemical processing enterprises (site A), while OVOCs were the majority at the other two sites, which were around by the fine chemical enterprises (site B and C). The TVOC concentrations presented seasonal differences at the three sites, which showed higher values in summer (468.6 μg/m3) at site A, in winter (409.2 μg/m3) at site B，and in autumn (298.9 μg/m3) at site C, respectively. The isopentane (16.8%) and ethylene oxide (17.9%) made up the largest proportion of the VOCs at site A and B, respectively. While it was more susceptible to the effects of dichloromethane, 1,2-dichloroethane and chloromethane at site C. Three pollution events of ethylene oxide, isopentane and dichloromethane were analyzed and traced based on the prevailing wind and the change of concentration at the three sites. Further analysis of the impact of VOCs on the formation of secondary pollutants of O3 and PM2.5 found that the contribution of local O3 (28.1 %) in summer was significantly larger in the study area than that in non-industrial area. The multiphase chemical reactions were more likely to occur in autumn, which promoted the formation of secondary PM2.5, showing the correlation coefficient of 0.73 between the secondary organic aerosol formation potential of VOCs and PM2.5.

Characterizing indoor air quality, thermal environment and window opening in natural-ventilated Norwegian bedrooms: An extensive field study

To generalize research on indoor air quality (IAQ) in bedrooms, the objective of this article is to characterize IAQ for the cold climate of Norway. The relationship between ventilation, indoor thermal environment and IAQ is revealed. 58 natural-ventilated bedrooms with different levels of renovation were investigated using detailed measurements during the heating season. Compared to other studies in Nordic climate, a larger fraction of the occupants used extensive window openings. A larger fraction of the bedrooms showed low CO2 concentrations. Only few other studies also measured TVOC concentrations. Its average value was well correlated with CO2. However, TVOC concentration is characterized by more peaks. Low CO2 concentrations were found with extensive window openings. Nonetheless, extensive window openings did not systematically lead to low CO2 concentrations, for instance the influence of curtains is shown. It is confirmed that the door opening can lead to relatively low CO2 concentrations when the window is closed. The highest CO2 concentrations are found with the window and door closed. The study confirms relatively low temperatures in bedrooms. Nevertheless, no clear correlation between the indoor temperature and the fraction of time with the window opened was observed. For instance, the lowest bedroom temperatures were obtained using window opening, but also with the window closed. Finally, the results suggest that it is possible to achieve a high IAQ with window ventilation when this is a deliberate strategy (if no filtering of the fresh air is needed), also in renovated buildings where the envelope airtightness has been improved.

Spatiotemporal distribution, source apportionment and health risk assessment of atmospheric volatile organic compounds using passive air samplers in a typical coastal area, China

To fully understand source characteristics and human health effects of atmospheric volatile organic compounds (VOCs), it is of great importance to implement long-term measurements, precise source apportionment and simulation. In this study, a 12-month measurement of VOCs was conducted in a coastal area in East China by a novel passive air sampler (PAS). A total of 28 VOC species, mainly in groups of aromatics and halohydrocarbons were observed. The monthly average concentrations of TVOC were as follows: industrial sites (154.10–727.19 μg m−3) > business sites (65.83–86.96 μg m−3) > residential sites (59.63–60.05 μg m−3) > background site (57.62 μg m−3). Their seasonal variation characteristics were: winter > spring > autumn > summer, which was more apparent at industrial sites due to human activities. Six VOC sources including industrial processes, organic solvents, dyeing, plastic synthesis, traffic emissions, and pesticides identified by the positive matrix factorization model compared favorably with the local emissions at industrial sites. Bromoform, hexachloro-1,3-butadiene, C1–C3 halogenated alkanes and benzene homologs could be the important indicators of industrial VOC emissions. The halohydrocarbons and aromatics were the major contributors to the ozone formation potential (OFP) and secondary organic aerosol potential (SOAP) in industrial areas, respectively. Both of OFP and SOAP have their maximum values in winter due to high VOC concentrations. Health risk assessment indicated that a high probability of non-carcinogenic risk (HI > 1) was in the region at 10 m height and 50m radius, and minor carcinogenic risk (CR > 10−6) was in the region at 70 m height and 1000 m radius. Among all the compounds, 1,2-Dibromo-3-chloropropane was the largest contributor with the individual HI value (17.99) and carcinogenic risk (5.34 × 10−3) at the peak. In this study, the PAS as a sampling tool was proven to be reliable and efficient for long-term measurements in coastal areas. It is worth to have further studies to promote passive sampling as an alternative to VOCs monitoring methods.

Exposure of Elderly People to Indoor Air Pollutants in Wanxia Nursing Home

The elderly residing in nursing homes are typically more advanced in age, have more health issues, and spend more time indoors than other elderly people. This study explored the indoor air quality in the Wanxia nursing home, the largest private nursing home in Chengdu, China, based on long-term measurement data. Air pollutant sensors measured the level of air pollution in the Wanxia nursing home from March 2021 to February 2022. This study obtained several important results: (1) The indoor air quality index (IAQI) of the Wanxia nursing home was at a low pollution level in spring, summer, and autumn, and at a moderate pollution level in winter. PM concentration played the most important role in determining indoor air quality; (2) During winter, the 24 h mean indoor concentrations of PM2.5 and PM10 were close to or even exceeded the standard limits. During winter and summer nights, indoor CO2 levels were very close to or greater than 1000 ppm. During spring and summer nights, the indoor TVOC concentrations exceeded the limit (0.45 mg/m3); (3) Apart from HCHO concentrations in autumn, the levels of other indoor air pollutants were significantly influenced by their outdoor levels. In addition, the seasonal indoor/outdoor (I/O) ratios of CO2 and TVOCs exceeded 1; and (4) Indoor CO2 levels were closely related to indoor temperature (Ta) and relative humidity (RH) in each season. PM10 concentration correlated with Ta and RH in summer, while PM2.5 concentration did not correlate with Ta and RH in winter. The indoor TVOC level positively correlated with RH. Lastly, the indoor HCHO level was minimally influenced by changes in Ta and RH. Due to the above results, this study proposes targeted strategies for improving indoor air quality in nursing homes.

Influence of indoor volatile organic compounds and its relative respiratory effects among children living in rural biomass cooking households of Tamil Nadu and Andhra Pradesh.

Exposures to volatile organic compounds (VOCs) cause respiratory symptoms among children, a known vulnerable group. Reports on exposures to VOCs and respiratory symptoms among South Indian children living in biomass-using households are not available thus far. A cross-sectional study was conducted among 313 rural children to assess the influence of emitted VOCs on their respiratory health. Standard analytical procedures for VOCs and Pulmonary Function Test (PFT), allied questionnaires, and all ethical considerations were fulfilled in the study. The increase in VOC concentrations was observed proportional to the amount of burnt biomass fuel in two selected sites in Tamil Nadu (TN) and Andhra Pradesh (AP). Houses cooked for more than 60min showed a remarkable increase in VOC concentrations and was observed as statistically significant (p < 0.01) in AP households. Among the younger children, the peak expiratory flow rate (PEFR) values were found significantly higher than comparatively older children in both the sites, TN and AP. However, the trend with respect to FEV1 is statistically significant (p < 0.01) among AP children. This study reports reduced lung function for a considerable proportion of the VOC-exposed selected children. Based on PFT, the children who were interpreted to be normal were found to be exposed to lesser indoor TVOC concentrations in comparison with the children of the households having restrictive or obstructive impairments. Diagnostic ratios with Benzene/Toluene (B/T) and Xylene/Ethyl benzene (X/E) confirmed the presence of VOCs-emissions from adjacent cooking fuels only. The observed results of this study recommends cleaner cooking fuel-use for better respiratory health among the citizens across the country, which in turn, in line with the Pradhan Mantri Ujjwala Yojana (PMUY), Government of India.

Assessment of the impacts of balconies on indoor environmental quality in mild climate conditions, Portugal

ABSTRACT The configuration of balconies can affect the indoor environmental performance of dwellings, but there is not enough knowledge regarding how a balcony simultaneously impacts all the parameters of indoor environmental quality (IEQ). Therefore, this study aims to evaluate, for the first time, the impacts of different balcony configurations on IEQ. A comprehensive in-situ campaign was carried out on ten balconies and their contiguous rooms in a building in Porto. Air temperature, relative humidity, CO2, PM2.5 and TVOCs concentration, illuminance and sound pressure level were simultaneously monitored. The results show that an open balcony has a positive impact on hygrothermal conditions, controlled daylight illuminance, and reduced traffic noise by up to 10 dBa. The presence of a glazed balcony improved hygrothermal conditions in winter and increased the noise reduction by up to 15 dBA, but caused a reduction in the daylight of up to 64%. The rooms, in which the balcony was eliminated presented the worst hygrothermal conditions, lost the benefits of noise reduction and had an increase in daylight illuminance of up to 136%. It was also found that the impacts are interrelated and that a balcony influences the occupants’ behaviour by enhancing window opening.

Factors affecting multiple chemical sensitivity (MCS) in newly constructed apartments of Indonesia

In Indonesia, sick building syndrome (SBS) and related health problems possibly caused by chemicals are suspected among residents in newly constructed urban houses, in which modern building materials are used without sufficient material standards and the minimum ventilation rates. This paper analyzes the causal relationships of factors affecting multiple chemical sensitivity (MCS) in urban houses in Indonesia. The measured IAQ data from three major cities of Indonesia (n = 207) were calibrated, and a structural equation modeling (SEM) was performed to identify the factors affecting MCS from a questionnaire survey in apartments and Kampong (n = 896). The results showed that the respondents living in a higher concentration of either formaldehyde or TVOC tended to have higher MCS risk, especially in the apartments. Overall, the apartments exhibited poor air quality rates, with the average maximum values of 0.172 ppm formaldehyde and 1.64 mg/m3 TVOC, potentially resulting in allergic problems and MCS risk among residents. In Kampongs, the building age was observed to increase the dampness, thereafter possibly causing allergies and MCS among residents. The results of this study implied that higher MCS in the apartments was majorly affected not only by their allergic conditions but also by additional factors concerning building attributes and occupant behavior.

Indoor Volatile Organic Compounds: Concentration Characteristics and Health Risk Analysis on a University Campus.

Volatile organic compounds (VOCs) are major indoor air pollutants that contain several toxic substances. However, there are few studies on health risk assessments of indoor VOCs in China. This study aimed to determine the concentration characteristics of VOCs on college campuses by collecting VOC samples from different locations on campus during different seasons combined with the exposure times of college students in each location obtained from a questionnaire survey to assess the possible health risks. The highest total VOC concentration (254 ± 101 µg/m3) was in the dormitory. The seasonal variation of TVOC concentrations was related to the variation of emission sources in addition to temperature. Health risk assessments of VOCs were evaluated using non-carcinogenic and carcinogenic risk values, represented by hazard quotient (HQ) and lifetime cancer risk (LCR), respectively. The non-carcinogenic risks at all sampling sites were within the safe range (HQ < 1). Dormitories had the highest carcinogenic risk, whereas the carcinogenic risk in the other three places was low (with LCR < 1.0 × 10-6). Moreover, 1,2-dichloroethane was identified as a possible carcinogenic risk substance in the dormitory due to its high LCR (1.95 × 10-6). This study provides basic data on health risks in different locations on campus and a basis for formulating measures to improve people's living environments.

Human personal air pollution clouds in a naturally ventilated office during the COVID-19 pandemic

Personal cloud, termed as the difference in air pollutant concentrations between breathing zone and room sites, represents the bias in approximating personal inhalation exposure that is linked to accuracy of health risk assessment. This study performed a two-week field experiment in a naturally ventilated office during the COVID-19 pandemic to assess occupants’ exposure to common air pollutants and to determine factors contributing to the personal cloud effect. During occupied periods, indoor average concentrations of endotoxin (0.09 EU/m3), TVOC (231 μg/m3), CO2 (630 ppm), and PM10 (14 μg/m3) were below the recommended limits, except for formaldehyde (58 μg/m3). Personal exposure concentrations, however, were significantly different from, and mostly higher than, concentrations measured at room stationary sampling sites. Although three participants shared the same office, their personal air pollution clouds were mutually distinct. The mean personal cloud magnitude ranged within 0–0.05 EU/m3, 35–192 μg/m3, 32–120 ppm, and 4–9 μg/m3 for endotoxin, TVOC, CO2, and PM10, respectively, and was independent from room concentrations. The use of hand sanitizer was strongly associated with an elevated personal cloud of endotoxin and alcohol-based VOCs. Reduced occupancy density in the office resulted in more pronounced personal CO2 clouds. The representativeness of room stationary sampling for capturing dynamic personal exposures was as low as 28% and 5% for CO2 and PM10, respectively. The findings of our study highlight the necessity of considering the personal cloud effect when assessing personal exposure in offices.

Hazard Evaluation of Indoor Air Quality in Bank Offices

IAQ is a crucial factor affecting the health, comfort, and productivity of workers, particularly those working in enclosed spaces like bank offices. This study aimed to evaluate the IAQ of a bank office’s operational area and vault by analyzing concentrations of CO2, TVOC, PM10, and PM2.5, as well as temperature, relative humidity, and air movement. Two different ventilation systems were compared to assess their impact on IAQ. The acquired data were statistically analyzed using mean comparison t-tests and hazard ratio analysis. The results revealed that indoor concentrations of PM2.5 and CO2 significantly contribute to the total hazard ratio, indicating the need to reduce their levels below reference values. The study also found that the ventilation system significantly affects indoor air quality, and concentrations of TVOC, CO2, PM10, and PM2.5 in the air are considerable. Significantly, the study found that bank offices with split unit air-conditioners had the highest mean CO2 levels, indicating poor ventilation. Overall, the study reveals that the building, activities, and ventilation in bank offices have a profound influence on IAQ parameters, primarily PM2.5 and CO2. Further research is required to formulate strategies for enhancing IAQ in these settings.