Indoor Microenvironments Research Articles

Persistent Organic Contaminants in Dust from the International Space Station.

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), "novel" brominated flame retardants (NBFRs), organophosphate esters (OPEs), polycyclic aromatic hydrocarbons (PAH), perfluoroalkyl substances (PFAS), and polychlorinated biphenyls (PCBs) were measured in a composite sample of dust from the International Space Station (ISS). Notwithstanding the unique environment from which the dust originated, while concentrations of all target compound classes frequently exceeded the median values in terrestrial indoor microenvironments in the US and western Europe, ISS dust concentrations were generally within the terrestrial range. The relative abundance of the three HBCDD diastereomers is dominated by γ-HBCDD (96.6% ΣHBCDD). This matches very closely with the commercial mixture added to materials and contrasts with the diastereomer distribution observed in most terrestrial indoor dust samples (in which γ-HBCDD is typically ∼60-70% ΣHBCDD). This suggests conditions inside the ISS do not favor the previously reported photolytically mediated formation in dust of α-HBCDD. Also of note, the concentration of perfluorooctanoic acid (PFOA) in ISS dust (3300 ng/g) exceeds the maximum reported (1960 ng/g) in a 2008 survey of dust from US child daycare centers and homes. This may reflect the widespread use of waterproofing treatments in the ISS to prevent microbial growth. Our findings can inform future material choices for manned spacecraft such as the ISS.

Arbovirus Transmission Predictions Are Affected by Both Temperature Data Source and Modeling Methodologies across Cities in Colombia.

Weather variables has been described as major drivers of vector proliferation and arbovirus transmission. Among them, temperature has consistently been found to be impactful in transmission dynamics, and models that incorporate temperature have been widely used to evaluate and forecast transmission or arboviruses like dengue, zika, or chikungunya virus. Further, there is growing evidence of the importance of micro-environmental temperatures in driving transmission of Aedes aegypti-borne viruses, as these mosquitoes tend to live within domiciles. Yet there is still a considerable gap in our understanding of how accounting for micro-environmental temperatures in models varies from the use of other widely-used, macro-level temperature measures. This effort combines field-collected data of both indoor and outdoor household associated temperatures and weather station temperature data from three Colombian cities to describe the relationship between the measures representing temperature at the micro- and macro-levels. These data indicate that weather station data may not accurately capture the temperature profiles of indoor micro-environments. However, using these data sources, the basic reproductive number for arboviruses was calculated by means of three modeling efforts to investigate whether temperature measure differences translated to differential transmission predictions. Across all three cities, it was determined that the modeling method was more often impactful rather than the temperature data-source, though no consistent pattern was immediately clear. This suggests that temperature data sources and modeling methods are important for precision in arbovirus transmission predictions, and more studies are needed to parse out this complex interaction.

Indoor air quality in day-care centres: a global review.

The online version contains supplementary material available at 10.1007/s11869-023-01320-5.

Presence, source attribution, and human exposure to organophosphate esters in indoor dust from various microenvironments in Nigeria

Very few studies have reported the presence of the organophosphate esters (OPEs) in African indoor microenvironments. We therefore document here, the concentrations, profiles, and human exposure to eight organophosphate esters (OPEs) for the first time in indoor dust from various microenvironments in Nigeria, specifically: cars/buses (n = 10), homes (n = 20), offices (n = 20), and medical centres (n = 14). The concentrations of OPEs in these indoor dust samples were among the lowest reported internationally. Concentrations of ∑8OPEs varied substantially between individual samples and the predominant OPEs were: tris(2-butoxyethyl) phosphate (TBOEP) (detection frequency (DF) = 90–100%), tris(1-chloro-2-propyl) phosphate (TCIPP) (DF = 100%), and 2-ethylhexyl-diphenyl phosphate (EHDPP) (DF = 100%). There were no significant differences (P˃0.05) between ∑8OPEs concentrations in dust samples from cars/buses (average = 295 ng/g), offices (231 ng/g), homes (277 ng/g), and medical centres (127 ng/g). Concentrations of chlorinated OPEs: tris(2-chloroethyl) phosphate (TCEP), TCIPP, and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were significantly correlated with those of triphenyl phosphate (TPhP), EHDPP, and TBOEP. Estimated daily intakes (EDI) of target OPEs via indoor dust ingestion and dermal absorption were lower than the corresponding reference dose (RfD) values, indicating that exposure to the studied OPEs in the indoor environment does not pose a significant health risk for the general population in Nigeria, even under a high-end exposure scenario.

Organophosphate esters in indoor and outdoor air in Birmingham, UK: implications for human exposure

We report concentrations of organophosphate esters (OPEs) in air from living rooms, bedrooms, and offices in Birmingham, UK. To place concentrations in these commonly frequented indoor microenvironments in context, we also measured the same OPEs in air samples collected from an outdoor location on the University of Birmingham campus. Concentrations of tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), and tri-n-butyl phosphate (TnBP) in indoor air significantly exceeded (P > 0.05) those in outdoor air. In contrast, concentrations of tris(1,3-dichloroisopropyl) phosphate (TDCIPP), triphenyl phosphate (TPhP), and 2-ethylhexyl diphenyl phosphate (EHDPP) in indoor and outdoor air were statistically indistinguishable (P < 0.05). Comparison of estimates of human exposure via inhalation derived from our data with previous estimates of exposure via dust ingestion, diet, drinking water, and dermal contact with furniture reveals that inhalation is the most important contributor to aggregate UK adult exposure to TCIPP (85% exposure) and TCEP (67% exposure). While average aggregate exposures of UK adults were well below health-based reference dose values, continued evaluation of human exposure is recommended as high-end exposures of some individuals (e.g., those inhabiting microenvironments containing concentrations of TCIPP at the high end of the range reported here) likely exceed substantially average exposures.

A new insight into the emission source of DDT in indoor environment from rural area of South China and comprehensive human health exposure assessment.

Human exposure to dichlorodiphenyltrichloroethanes (DDTs) and the subsequent risk to human health remain an important concern due to the "new" input of DDTs in the environment, especially since exposure to DDTs in indoor microenvironments is often ignored. In this study, we identified a new source of DDT emission in indoor environments and evaluated the health risk from the exposure to DDTs by investigating DDTs in indoor and outdoor dust, air, and coatings of household items in rural areas of Qingyuan, South China. The concentrations of DDTs in house dust and air were < MQL (method quantification limit)-3450ng/g (median 42.4ng/g) and 22.7-965pg/m3 (median 49.5pg/m3), respectively, which were significantly higher than the outdoor DDT values. Dichlorodiphenyldichloroethylene (DDE) was the main isomer in air samples, while DDT was the dominant isomer in indoor dust. Significant correlations between different DDT isomers were observed in indoor samples but not in outdoor samples. Furniture coating was identified as a source of DDTs in the indoor dust. The total daily exposure dose of DDTs (1.75 × 10-2ng/kg bw/day for adults and 1.28 × 10-1ng/kg bw/day for toddlers) through inhalation, dust ingestion, and dermal contact was found unlikely to pose a health risk. Our findings provide new insights into the emission sources and health risks caused by DDT indoors, highlighting the need to further investigate the toxicity mechanisms of parent DDT compound.

Automated classification of time-activity-location patterns for improved estimation of personal exposure to air pollution.

Air pollution epidemiology has primarily relied on measurements from fixed outdoor air quality monitoring stations to derive population-scale exposure. Characterisation of individual time-activity-location patterns is critical for accurate estimations of personal exposure and dose because pollutant concentrations and inhalation rates vary significantly by location and activity. We developed and evaluated an automated model to classify major exposure-related microenvironments (home, work, other static, in-transit) and separated them into indoor and outdoor locations, sleeping activity and five modes of transport (walking, cycling, car, bus, metro/train) with multidisciplinary methods from the fields of movement ecology and artificial intelligence. As input parameters, we used GPS coordinates, accelerometry, and noise, collected at 1 min intervals with a validated Personal Air quality Monitor (PAM) carried by 35 volunteers for one week each. The model classifications were then evaluated against manual time-activity logs kept by participants. Overall, the model performed reliably in classifying home, work, and other indoor microenvironments (F1-score>0.70) but only moderately well for sleeping and visits to outdoor microenvironments (F1-score=0.57 and 0.3 respectively). Random forest approaches performed very well in classifying modes of transport (F1-score>0.91). We found that the performance of the automated methods significantly surpassed those of manual logs. Automated models for time-activity classification can markedly improve exposure metrics. Such models can be developed in many programming languages, and if well formulated can have general applicability in large-scale health studies, providing a comprehensive picture of environmental health risks during daily life with readily gathered parameters from smartphone technologies.

Phytoremediation potential of indoor plants in reducing air pollutants

Indoor air quality (IAQ), specifically after the COVID-19 pandemic, has become an international issue, as humans spend 80–90% of their time in indoor microenvironments. Poor IAQ has been related to the sick-building syndrome, nasal and ocular irritations, allergies, and respiratory dysfunction, including premature deaths. Phytoremediation is a novel strategy to absorb, adsorb, assimilate or transfer/reduce air pollutants and improve the IAQ using plants. Hence, the current review aims to explore indoor plants' role in improving indoor air quality, including their purification capabilities. There is increasing evidence that various plant species (e.g., Ficus benjamina, Chlorophytum comosum, Draceana) or their parts can reliably reduce the concentration of numerous air pollutants in the indoor microenvironment and promote human wellbeing. However, the indoor air pollutants removal efficiency depends on the species of plant, various plant characteristics such as leaf size, thickness, area, photosynthetic activity, light intensity and part of plant involved, i.e., roots, leaves, wax, cuticle and stomata. Using indoor plants is one of the most cost-effective and reliable methods of making a healthier indoor environment. Better public health can be maintained at a lower cost, with less strain on the health care system, if more emphasis is placed on creating a biophilic atmosphere and increasing the use of indoor plants. However, there are no established criteria for the best indoor plants and the impact of indoor plants on various factors such as interior ventilation, temperature, humidity, etc. Therefore, further experimental research is needed that simulates the interior environment to monitor the impacts of indoor plants on factors such as humidity, temperature, ventilation, etc., in improving the microenvironment of a closed space/room.

Analysis of airborne fungal spore content in different indoor microenvironments in the Cathedral of Jaén (South Spain)

Analysis of airborne fungal spore content in different indoor microenvironments in the Cathedral of Jaén (South Spain)

Application of the low-cost sensing technology for indoor air quality monitoring: A review

In recent years, low-cost air pollution technologies have gained increasing interest and, have been studied widely by the scientific community. Thus, these new sensing technologies must provide reliable data with good precision and accuracy. Accordingly, this review aimed to evaluate and compare the low-cost sensing technology against other instruments used for comparison by various studies from the scientific literature to monitor indoor air quality in different indoor environments. After exclusions, a total of 42 studies divided into two subsections (11 laboratory studies and 31 field studies) were analysed considering their aim, location, study duration, sampling area, pollutant(s) evaluated, sensor/device and instrument used for comparison, performance indexes and main outcomes. The reviewed studies aimed to assess different low-cost sensors/devices to monitor indoor air quality against other instruments used for comparison. The vast majority of the studies took place in USA. The laboratory studies were mainly conducted in a controlled chamber, and field studies were performed in homes, offices, educational buildings, among others. In both cases, particulate matter was the most assessed pollutant, either with commercial devices (e.g.: Speck, Dylos, Foobot) or sensors (e.g. Sharp GP2Y1010AU0F). In general, based on statistical parameters, the air quality low-cost sensors/devices tested presented moderate correlations with the instruments used for comparison, revealing sufficient precision for monitoring air quality in indoor microenvironments, especially for qualitative analysis. Thus, low-cost sensing technology to monitor indoor air quality is encouraged, but not waiving the relevance of high quality instruments (mainly reference instruments). • Indoor air quality sensing technologies should provide reliable and accurate data. • Low-cost sensors/devices showed moderate correlations with comparison instruments. • PM was the most studied pollutant tested by the low-cost devices and sensors. • Low-cost technologies to monitor indoor air quality is cautiously encouraged.

Assessment of the exposure to PM2.5 in different Lebanese microenvironments at different temporal scales.

The weak potential of using the sole outdoor concentrations to represent personal exposure to PM2.5 is confirmed by the literature; therefore, it is important to account for a person’s movements over time when estimating the short-term personal air pollution exposure within different microenvironments (MEs). This study is an example of applying an assessment method of the exposure to PM2.5 in different microenvironments at different temporal scales. A low-cost particle counter (the Dylos 1700) was used; its performance was validated in comparison with equivalent instruments such the SidePak AM520 Personal Aerosol Monitor (R2 = 0.89). This validation also provided a function to convert measured particle number concentrations (PNCs) into calculated particle mass concentrations. The 150 profiles that was collected on a minute-by-minute basis regarding PM2.5 concentration from December 2018 to May 2021 highlight the influence of individual activities and contextual factors on the air quality, so that Lebanon’s annual PM2.5 mean (24.2 µg⁄m3) is 142% higher than the World Health Organization (WHO) annual mean guideline (10 µg⁄m3). Winter is the most polluted period due to the increased application of space heating devices. Additionally, the occurrence of dusty winds during the spring period leads to the elevated levels of dispersed PM2.5. Simultaneously, the rural zones are more polluted than urban ones due to the usage of more traditional heating equipment, in addition to the usage of chemical products like pesticides and fertilizers in agricultural activities in such areas. Furthermore, the (outdoor–indoor–transport) MEs indicate that the transport and indoor MEs have similar levels of suspended fine particulates, while outdoor MEs are less polluted. Studies based on the personal exposure to PM2.5 were generally applied on specific and limited places such as schools, workplaces, or residences. The study aims to shed light on the modern method in an attempt to estimate the personal exposure to PM2.5 and to inspire similar studies to achieve the maximum efficiency.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10661-022-10607-6.

Distribution of flame retardants among indoor dust, airborne particles and vapour phase from Beijing: spatial–temporal variation and human exposure characteristics

The occurrence and distribution of 10 brominated flame retardants (BFRs) and 10 organophosphate flame retardants (OPFRs) were investigated in indoor dust, total suspended particles (TSP), and vapour phase from offices (n = 10), homes (n = 9), and day-care centres (n = 10) in Beijing, China. Three types of samples were collected biweekly from one office and one home over a year to examine temporal trends. BFRs in dust significantly correlated with those in TSP, while OPFRs significantly correlated among all three matrices. In addition, BFRs in dust (ng/g) and TSP (pg/m3) exhibited similar temporal trends with higher levels in the cold season, whereas OPFRs in TSP and vapour phase (pg/m3) showed similar temporal trends with higher levels in the warm season. The geometric mean concentrations of BFRs and OPFRs in the three matrices from the above mentioned three types of indoor microenvironments were used for exposure and health risk estimation, and ∑7OPFRs showed much higher hazard index (HI) values than ∑10BFRs for all subpopulations, and inhalation of OPFRs was a major risk source. With the volatility of flame retardants (FRs) decreasing, the contribution of dust ingestion and dermal absorption showed an increasing trend, and the contribution of inhalation exhibited a gradual decreasing trend, which implied the dominant exposure pathway to FRs is strongly related to the vapour pressure (25 °C, Pa) of these substances. Using a single type of microenvironment or the collection of samples at a single point in time can lead to overestimation or underestimation of overall exposure and risk for people to some extent. The correlations of FRs in dust, TSP, and vapour phase from indoor microenvironments, as well as their temporal trends were first reported in this study, which will provide a basis for more accurate FR exposure assessments in the future.

High contribution from outdoor air to personal exposure and potential inhaled dose of PM2.5 for indoor-active university students

People spend most of their time indoors, isolated from the outdoor environment where serious air pollution usually occurs. To what extent outdoor air pollution contributes to their daily personal exposure and inhaled dose? To fill this knowledge gap, an exposure assessment study was conducted for indoor-active university students during a wintertime period of hazy and non-hazy (clear) days in Beijing. Indoor and outdoor fine particulate matter (PM2.5) samples were collected at six indoor microenvironments, and two outdoor environments representing traffic and ambient exposure in the university, respectively, to estimate the personal exposure of students. The average daily personal exposure and poteantial inhaled dose on hazy days (124.8 ± 72.3 μg m−3 and 2.74 ± 1.53 mg) were much higher than that on clear days (57.5 ± 31.9 μg m−3 and 1.26 ± 0.59 mg), indicating a significant influence from the ambient air quality. The indoor PM2.5 concentrations were significantly and positively correlated with the outdoor ones (r = 0.67–0.96) with an FINF (infiltration factor) range of 0.44–0.81 during sampling periods. The outdoor-origin air contributed 68%–95% to the total indoor PM2.5, the average of which was higher during haze events (87%) than clear periods (73%). Correspondingly, outdoor-origin PM2.5 contributed around 105.4 μg m−3 and 2.41 mg (85% and 89%) to the daily exposure and inhaled dose of college students on hazy days, respectively, compared to just 39.2 μg m−3 and 0.95 mg (68% and 75%) on clear days. Our results highlight the significant contribution of outdoor-origin PM2.5 occurred indoor to both the daily personal exposure and inhaled dose due to air pollution filtration between outdoor and indoor environments. These also suggest a continuous effort not only on ambient air quality improvements, but also on environmental friendly building for public health protection with lower exposure.

Profiling of multiple classes of flame retardants in house dust in China: Pattern analysis and human exposure assessment

Legacy [e.g., brominated- (BFRs)] and alternative [e.g., organophosphate- (OPFRs) and nitrogenous- (NFRs)] flame retardants have a propensity to migrate out of consumer products, and thus are dispersed in indoor microenvironments. In this study, simultaneous presence of 11 BFRs, 18 OPFRs and 11 NFRs were measured in house dust collected from Tianjin, China. OPFRs were found at the highest concentrations, with a median value of 3200 ng/g, followed by NFRs (2600) and BFRs (1600). Tris(2-butoxyethyl) phosphate (median: 1800 ng/g), melamine (1100), and BDE-209 (870) were the top three most abundant chemicals in the respective groups. Location-specific patterns of flame retardant concentrations were found with 30%, 20% and 10% of samples were predominated by OPFRs, NFRs and BFRs, respectively, and the remaining samples contained by two or more of the chemical groups occurring concurrently. Network and cluster analysis results indicated the existence of multiple sources of flame retardants in the indoor microenvironment. Estimated human daily intakes via indoor dust ingestion were approximately several tens of ng/kg bw/day and were below their respective reference dose values. Our results indicate widespread occurrence of multiple flame retardant families in indoor dust and suggest need for continued monitoring and efforts to reduce exposures through dust ingestion.

The influence of formaldehyde removal finishing on fogging characteristics and properties of polyester fabrics

The air quality in the vehicle indoor microenvironment has been of particular public concern because of its harmful effect on the human body. The volatile and semivolatile organic compounds in the vehicle indoor air can condense onto the cooler surface of the windshield, potentially creating a visibility and safety problem for the driver. This paper aimed to prepare multifunctional polyester fabrics with formaldehyde removal properties and low fogging degrees. The formaldehyde removal finishing of polyester fabrics was carried out with different formaldehyde removal agents using the pad-dry-cure method. The influence of formaldehyde removal finishing on the formaldehyde removal efficiency, fogging degree and some related performances of polyester fabrics are studied. The results show that the fogging degree increased (lower than standard values: 2 mg) after finishing with formaldehyde removal agents FK-1, FK-2, FK-3, FK-5, and FK-6. The formaldehyde removal rate of polyester fabrics after finishing was above 75%, and the performances of water repellence, softening behavior, color fastness were maintained. Our approach provides an easy method for use in vehicle indoor air purification systems and the finished fabrics can be applied to various applications such as home, automobile, office, and industry.

Modeling Clothing as a Vector for Transporting Airborne Particles and Pathogens across Indoor Microenvironments.

Evidence suggests that human exposure to airborne particles and associated contaminants, including respiratory pathogens, can persist beyond a single microenvironment. By accumulating such contaminants from air, clothing may function as a transport vector and source of “secondary exposure”. To investigate this function, a novel microenvironmental exposure modeling framework (ABICAM) was developed. This framework was applied to a para-occupational exposure scenario involving the deposition of viable SARS-CoV-2 in respiratory particles (0.5–20 μm) from a primary source onto clothing in a nonhealthcare setting and subsequent resuspension and secondary exposure in a car and home. Variability was assessed through Monte Carlo simulations. The total volume of infectious particles on the occupant’s clothing immediately after work was 4800 μm3 (5th–95th percentiles: 870–32 000 μm3). This value was 61% (5–95%: 17–300%) of the occupant’s primary inhalation exposure in the workplace while unmasked. By arrival at the occupant’s home after a car commute, relatively rapid viral inactivation on cotton clothing had reduced the infectious volume on clothing by 80% (5–95%: 26–99%). Secondary inhalation exposure (after work) was low in the absence of close proximity and physical contact with contaminated clothing. In comparison, the average primary inhalation exposure in the workplace was higher by about 2–3 orders of magnitude. It remains theoretically possible that resuspension and physical contact with contaminated clothing can occasionally transmit SARS-CoV-2 between humans.

Factors Influencing Classroom Exposures to Fine Particles, Black Carbon, and Nitrogen Dioxide in Inner-City Schools and Their Implications for Indoor Air Quality

Background:School classrooms, where students spend the majority of their time during the day, are the second most important indoor microenvironment for children.Objective:We investigated factors influencing classroom exposures to fine particulate matter (), black carbon (BC), and nitrogen dioxide () in urban schools in the northeast United States.Methods:Over the period of 10 y (2008–2013; 2015–2019) measurements were conducted in 309 classrooms of 74 inner-city schools during fall, winter, and spring of the academic period. The data were analyzed using adaptive mixed-effects least absolute shrinkage and selection operator (LASSO) regression models. The LASSO variables included meteorological-, school-, and classroom-based covariates.Results:LASSO identified 10, 10, and 11 significant factors () that were associated with indoor , BC, and exposures, respectively. The overall variability explained by these models was , 0.687, and 0.621 for , BC, and , respectively. Of the model’s explained variability, outdoor air pollution was the most important predictor, accounting for 53.9%, 63.4%, and 34.1% of the indoor , BC, and concentrations. School-based predictors included furnace servicing, presence of a basement, annual income, building type, building year of construction, number of classrooms, number of students, and type of ventilation that, in combination, explained 18.6%, 26.1%, and 34.2% of , BC, and levels, whereas classroom-based predictors included classroom floor level, classroom proximity to cafeteria, number of windows, frequency of cleaning, and windows facing the bus area and jointly explained 24.0%, 4.2%, and 29.3% of , BC, and concentrations, respectively.Discussion:The adaptive LASSO technique identified significant regional-, school-, and classroom-based factors influencing classroom air pollutant levels and provided robust estimates that could potentially inform targeted interventions aiming at improving children’s health and well-being during their early years of development. https://doi.org/10.1289/EHP10007

INVESTIGATION OF NOISE EXPOSURES, PERCEPTION, AND HEALTH EFFECTS IN DIFFERENT MICROENVIRONMENTS IN A UNIVERSITY COMMUNITY

This study aims to assess noise levels in selected outdoor and indoor microenvironments in a University community in Oman. The perception of noise levels within the Sultan Qaboos University campus was investigated through a survey study. Also, the effect of exposed noise levels on annoyance and sleep disturbance were predicted including their potential risk on cardiovascular health. Among all the measured parameters, it was found that outdoor (41.6%-50%) and indoor (38.5%-46.2%) microenvironments have exceeded the critical levels of 55 dB during morning and afternoon periods. The respondents (698 people) identified traffic and indoor building-related activities as the main sources of noise levels but the majority (44%) of them rated their impact as low. However, more than 30% of the respondents considered traffic as the main contributor to University noise levels. The percentage of highly annoyed persons was predicted to be high in outdoor areas especially in the residential (25%) and near the hospital (13%) areas. However, indoor environments including construction materials and structures labs (14%) showed similar annoyance rates. Also, the percentage of high sleep disturbed persons was found higher in residential areas (7.4%) areas compared to hospital areas (5.3%) locations. The study concluded that there might be an association between the exposed noise levels and the risk of developing cardiovascular diseases. This is the first study that has provided a high spatial variability noise exposure levels across a University environment in Oman, this will contribute to designing future sustainable mitigation strategies to improve the health and well-being of the exposed population. The study has provided a baseline knowledge needed for future epidemiological studies.

Bioaccessibility-based monitoring and risk assessment of indoor dust-bound PAHs collected from housing and public buildings: Effect of influencing factors.

Polycyclic aromatic hydrocarbons (PAHs) bounded in indoor dust have significant effects in residents' health. Although various researches has evaluated exposure to PAHs in some indoor areas around the world, no work has been conducted on bioaccessibility of indoor PAHs in the buildings of Bushehr city. Therefore, dust samples were collected from various indoor microenvironments including residential buildings (RB), office buildings (OB), commercial buildings (CB), industrial buildings (IB), school classroom (SC), laboratory (LR), drugstores (DS), beauty salons (BS), smoking cafés (SC) and restaurants (Res) - 10 from each microenvironment. In order to determine the levels of polycyclic aromatic hydrocarbons (PAHs), bioaccessible PAHs, and sink sorption PAHS were analyzed in them. The results showed that the highest level of these contaminants was detected in SC and the lowest in Lab. The median concentration of dust-bound ΣPAHs, bioaccessible ΣPAHs, and sink sorption ΣPAHs in the SC samples were 10,890.00, 1157.92, and 297.28ng/g, and they were 1160.00, 19.69, and 0.75ng/g in Lab samples. The results also indicated that the ΣPAHs concentration had a negative and significant association with the ventilation rate (pvalue <0.05 in most cases), as well as a positive and significant relationship with smoking inside buildings (pvalue <0.05). The estimated daily intake (EDI) values calculated for residential buildings (RB) were higher compared to most of the other studied microenvironments. These observations can be due to the fact that people spend much more time in residential buildings (50% of the entire day) compared to occupational settings (22%). Thus, they intake more dust within a longer time, and are hence exposed to larger amounts of pollutants bound with these particles.

Measurements and Analysis of Personal Exposure to RF-EMF Inside and Outside School Buildings: A Case Study at a Kosovo School

Today, society is facing the challenge of intensive Internet use. In addition to real-life situations, intense social media activity has raised concerns about personal exposure to RF-FEM from wireless communication systems, particularly indoors. We present the results of the measurements of personal exposure to children in school. In this case, it is about a large school in the capital of Kosovo-Pristina. This study aimed to obtain measured values that indicate the level of personal exposure to RF-EMF from wireless communication systems and usage of mobile phones and other wireless devices by students and staff during class hours. We compared the measured values on weekdays with those on weekends seeking changes and valid assessments of real-life situations. The exposure levels from Wi-Fi networks and cell phone systems were below the international reference levels and some EMF limits of precautionary laws in sensitive places. The values recorded for a typical Kosovo school were comparable to those in other countries, especially in indoor microenvironments. However, we noticed intense activity on mobile phones during classes. The average power density doubled on weekdays compared with weekends. The intensive traffic of mobile phones and Wi-Fi devices connected to the Internet outside the school building is also detected.