Indoor Air Samples Research Articles

Microplastics and nanoplastics science: collecting and characterizing airborne microplastics in fine particulate matter

Microplastic (MP) pollution in the environment is increasing, leading to growing concerns about human exposures and the subsequent impact on health. Although marine MP research has received significant attention in recent years, only a few studies have attempted characterization of MP in air and examined the MP uptake and influence via inhalation on human health. Moreover, the methods used for MP characterization in the marine environment require further optimization to be applicable to MP in the air. This paper details method for collecting and characterizing MP < 2.5 μm in air samples for the purposes of toxicological assessment. The first phase of the study evaluated (a) the suitability of various filter types to collect respirable airborne MP <2.5 μm, and; (b) the ability of Raman and enhanced darkfield-hyperspectral spectroscopy methods to identify MP reference standards collected from spiked filters and in cells after exposure to reference MP. In the second phase, these methods were employed to characterize MP <2.5 μm in personal, indoor and outdoor filter air samples and in cells following exposure to filter extracted material. The results showed the presence of a variety of MP in the respirable size fraction (0.1–1 µm aerodynamic diameter). Silver membrane filters were found not suitable for collecting and analyzing MP <2.5 μm. While it was easy to detect reference MP in cells post-exposure, the identity of only two types of air-borne MP was confirmed in cells. The study highlighted possible sources of artifacts and inconsistencies in analyzing airborne MP.

Indoor Air Quality including Respiratory Viruses.

The detection of SARS-CoV-2 in indoor environments is a cause of increasing concern. In this study, three sampling methodologies have been used in order to collect SARS-CoV-2 and 17 other respiratory viruses in indoor air, combined with a new analytical process to analyze respiratory viruses. Different areas of an ophthalmological hospital were investigated for the presence of these airborne viruses. Moreover, indoor air quality (IAQ) parameters (carbon dioxide, CO2; carbon monoxide, CO; nitrogen dioxide, NO2; volatile organic compounds, VOCs; formaldehyde, HCHO; and particulate matter, PM) have been examined to study the relationship between IAQ and airborne viruses. All indoor air and surface samples assessed were found to be negative for SARS-CoV-2. Nevertheless, another airborne respiratory virus (HRV/ENV) was detected, illustrating that the methodology set out here is a suitable one. Regarding the results for the IAQ, chemical parameters studied in the hall and waiting room of the hospital presented acceptable values. However, in the doctor′s consultation room VOCs and HCHO show some instantaneous levels higher than the recommended guide values. The methodological approach described in this paper, integrating conventional IAQ and the assessment of bioaerosols, can be used in research and control programs aimed at promoting a healthy indoor environment.

Characterization of microplastics in indoor and ambient air in northern New Jersey

Airborne microplastics (MPs) could have negative impacts on human health and pollute water, soil, and sediment. This study explored the distributions, compositions, and morphology of airborne microplastics in the indoor and ambient air in New Jersey, United States. Microplastic fibers, films, and fragments of Polystyrene (PS), Polyethylene terephthalate (PET), Polyethyelene (PE), Polyvinyl chloride (PVC) and Polypropylene (PP) were identified in office, hallway, classroom, and single-family house in this study. The deposition rates of synthetic fibers with length from 35 μm to 1000 μm were highest in the single-family house ((1.96 ± 1.09) × 104 fibers/m2/day) and lowest in the classroom ((6.20 ± 0.57) × 103 fibers/m2/day), suggesting that residential houses are a major source of microplastic fibers. However, for film-like plastics with surface areas ranging from 200 μm2 to 5000 μm2, a high deposition rate of (8.13 ± 2.17) × 103 films/m2/day was observed in the classroom, whereas the lowest deposition rate of (4.45 ± 0.27) × 103 films/m2/day was found in the hallway, probably because plastic films such as PE are intensively used in the classroom environments. The deposition rate of microplastics in the ambient air acquired on a building roof was only about 2–8% of the indoor deposition rates. The microplastics with similar textures but different sizes were identified in both total atmospheric deposition and particulate samples (PM2.5 and PM10), suggesting degradation from microplastics to nanoplastics. The main microplastics found in indoor air samples were PE fragments or fibers, different from those in the outdoor ambient air that were dominated by PVC fragments. These results unravel the properties of airborne microplastics in urban environments that are important to understanding their fate, transport, and potential health risks.

Emerging and legacy flame retardants in indoor air and dust samples of Tarragona Province (Catalonia, Spain)

Flame retardants (FRs) are widely used in consumer products including furniture foam and electronic equipment such as computers, monitors and TVs. Over time, FRs can easily migrate into the surrounding environments. Since brominated FRs (BFRs) has been determined of high concern due to their environmental persistence, bioaccumulation and potential toxicity, novel FRs have emerged. The present study was aimed at identifying and quantifying the indoor levels of 41 legacy and novel FRs, which include 20 OPFRs and 21 HFRs (8 PBDEs, 3 HBCDDs, 5 NBFRs and 5 DECs) in Tarragona Province (Catalonia, Spain). The results have confirmed the presence of both legacy and novel FRs in air and dust of homes, schools and offices. To the best of our knowledge, this is the first European study measuring OPFRs at office environments and also confirming the presence of the following OPFRs: TEP, TCIPP, T2IPPP, TPPO, DCP, TMCP and B4IPPPP in indoor air, even some of them at high levels. OPFRs in general and TCIPP in particular showed high concentrations in air (94,599 pg/m3 and 72,281 pg/m3, respectively) and dust (32,084 ng/g and 13,496 ng/g, respectively) samples collected in indoor environments. HBCDDs were found at high levels in dust (32,185 ng/g), whereas the presence of PBDEs and DECs were low in both matrices (<160 pg/m3 in air and <832 ng/g in dust). NBFRs showed higher levels than the two legacy FRs groups, which is supported by the current restrictions of these FRs (640 pg/m3 in air and 1291 ng/g in dust). Samples of schools had significantly lower levels of NBFRs, but significantly higher concentrations of HFRs in air than in home samples, while dust levels of HFRs were significantly lower than those in samples of offices. Regarding human health risks, the current assessment suggests that those derived from exposure to FRs were lower -although close- to assumable risks, evidencing the potential of FRs for non-carcinogenic and carcinogenic risks, mainly due to the exposure to TCIPP, which was the main contributor together with ΣHBCDDs and also EHDPP.

Volatile organic compounds (VOCs) in indoor air and tap water samples in residences of pregnant women living in an area of unconventional natural gas operations: Findings from the EXPERIVA study

BackgroundNortheastern British Columbia (Canada) is an area of unconventional natural gas (UNG) exploitation by hydraulic fracturing, which can release several contaminants, including volatile organic compounds (VOCs). To evaluate gestational exposure to contaminants in this region, we undertook the Exposures in the Peace River Valley (EXPERIVA) study. ObjectivesWe aimed to: 1) measure VOCs in residential indoor air and tap water from EXPERIVA participants; 2) compare concentrations with those in the general population and explore differences related to sociodemographic and housing characteristics; and 3) determine associations between VOC concentrations and density/proximity to UNG wells. MethodsEighty-five pregnant women participated. Passive air samplers were analyzed for 47 VOCs, and tap water samples were analyzed for 44 VOCs. VOC concentrations were compared with those from the Canadian Health Measure Survey (CHMS). We assessed the association between different metrics of well density/proximity and indoor air and tap water VOC concentrations using multiple linear regression. Results40 VOCs were detected in >50% of air samples, whereas only 4 VOCs were detected in >50% of water samples. We observed indoor air concentrations >95th percentile of CHMS in 10–60% of samples for several compounds (acetone, 2-methyl-2-propanol, chloroform, 1,4-dioxane, hexanal, m/p-xylene, o-xylene, styrene, decamethylcyclopentasiloxane, dodecane and decanal). Indoor air levels of chloroform and tap water levels of total trihalomethanes were higher in Indigenous participants compared to non-Indigenous participants. Indoor air levels of chloroform and acetone, and tap water levels of total trihalomethanes were positively associated with UNG wells density/proximity metrics. Indoor air BTEX (benzene, toluene, ethylbenzene, xylenes) levels were positively correlated with some well density/proximity metrics. ConclusionOur results suggest higher exposure to certain VOCs in pregnant women living in an area of intense unconventional natural gas exploitation compared with the general Canadian population, and that well density/proximity is associated with increased exposure to certain VOCs.

Trihalomethanes in exhaled air, indoor air and water: A parallel design trial in chlorine and ozone-chlorine disinfected swimming pools

We measured the concentrations of Trihalomethanes (THMs), Chloroform (TCM), Bromodichloromethane (BDCM), Dibromochloromethane (DBCM) and Bromoform (TBM), in water, indoor air and exhaled air before and after using chlorine and ozone-chlorine disinfected swimming pools from September 2020 to January 2021. Two parallel panels of adult subjects swam for 60 min in a chlorine and an ozone-chlorine indoor swimming pool. The concentration of total THMs (tTHMs) in water samples of chlorine and ozone-chlorine swimming pools were in the ranges of 170.8–192.5 μg/L and 161.3–180.4 μg/L, respectively which exceeded the WHO guideline value. High levels of THMs were found in indoor air at the height of 10 cm compared to 150 cm above water surface. We found a statistically significant correlation between the concentration of THMs in water and indoor air samples. The results showed that the levels of all detected THMs in participant’ exhaled air after 60 min swimming were 11–13 times higher than those of before exposure. A statistically significant linear correlation was observed between THMs levels in the exhaled air and indoor air at the height of 10 cm above the water surface, but not with the levels at the height of 150 cm. We also found that the levels of THMs in exhaled air were associated with the energy expenditure, swimming distance and time, but not correlated with BMI and skin area.

Presence of organophosphate flame retardants (OPEs) in different functional areas in residential homes in Beijing, China

The production and application of organophosphate esters (OPEs) have dramatically increased in recent years due to their use as a replacement for brominated flame retardants. In this study, 13 OPEs (Σ13OPEs) were analyzed in indoor air samples from kitchens and living rooms in 14 residential homes in Beijing, China. The concentrations of Σ13OPEs in kitchen air samples (mean: 13 ng/m3) were significantly (p < 0.05) higher than in living room air samples (5.0 ng/m3). In addition, paired window surface organic film samples were collected and analyzed to investigate film-air partitioning, exhibiting a mean concentration of Σ13OPEs of 4100 ng/m2. The congener profiles showed that tris(2-chloroisopropyl) phosphate (TCPP) was the predominant compound in both window film samples (48%) and the corresponding indoor air sample (56%). The estimated daily intakes (EDI) of OPEs via indoor air inhalation were 2.8 and 1.4 ng/kg/day for infants and adults, respectively, both of which are below the reference dose values (RfDs). Overall, these findings indicate that OPEs in the indoor air environment of residential homes in Beijing are not likely to pose a health risk to the general population.

Characteristics and health risks of benzene series and halocarbons near a typical chemical industrial park

Health risks of typical benzene series and halocarbons (BSHs) in a densely populated area near a large-scale chemical industrial park were investigated. Ambient and indoor air and tap water samples were collected in summer and winter; and the concentration characteristics, sources, and exposure risks of typical BSH species, including five benzene series (benzene, toluene, ethylbenzene, o-xylene, m,p-xylene) and five halocarbons (dichloromethane, trichloromethane, trichloroethylene, tetrachloromethane, and tetrachloroethylene), were analysed. The total mean concentrations of BSHs were 53.32 μg m−3, 36.29 μg m−3, and 26.88 μg L−1 in indoor air, ambient air, and tap water, respectively. Halocarbons dominated the total BSHs with concentrations relatively higher than those in many other industrial areas. Industrial solvent use, industrial processes, and vehicle exhaust emissions were the principal sources of BSHs in ambient air. The use of household products (e.g., detergents and pesticides) was the principal source of indoor BSHs. Inhalation is the primary human exposure route. Ingestion of drinking water was also an important exposure route but had less impact than inhalation. Lifetime non-cancer risks of individual and cumulative BSHs were below the threshold (HQ = 1), indicating no significant lifetime non-cancer risks in the study area. However, tetrachloromethane, benzene, trichloromethane, ethylbenzene, and trichloroethylene showed potential lifetime cancer risk. The cumulative lifetime cancer risks exceeded the tolerable benchmark (1 × 10−4), indicating a lifetime cancer risk of BSHs to residents near the chemical industry park. This study provides valuable information for the management of public health in chemical industrial parks.

Airborne Fungi in Prison Indoor Environments of Nsukka and Enugu Metropolis, Nigeria

Air borne fungi are transmitted through the air which can cause respiratory infections in human leading to allergies, asthma and diseases of the respiratory tract. The study is to determine the prevalence of fungi isolates in Enugu and Nsukka indoor prison environments and the possible effects on the respiratory tracts of the prison inmates. Institutions that accommodate large number of people such as Prisons, schools and hospitals are prone to airborne diseases due to overcrowded and unhygienic environment. The study was carried out using convenience sampling method and health based questionnaires. One hundred and forty (140)samples were analyzed consisting prison offices(48),inmates cells (28),lavatory (16),furniture(8),nasal swabs(20) and hostels(20). AC single impactor with high vacuum pump was used for indoor air sample collection; thermometer was used in measuring the temperature of the room and hygrometer for measuring the humidity. Sterile swab was used in collection of nasal samples, walls, furniture, toilets and bathrooms. Sabouraund dextrose agar (0.05µg Chloramphenicol and 1µg of Streptomycin), Malt extract agar, Chromagar, Brain heart infusion agar, and Nutrient agar were used for culture media for isolation of fungi respectively. The data generated from this research was analyzed using SPSS statistical software version 23.The result obtained showed that the percentage distribution of fungi isolates in prison offices were 60.9%, 57.4% in Nsukka and Enugu respectively while the percentage distribution percentage distribution of fungi isolates in prison cells were 42.6% and 39.1% in Enugu and Nsukka respectively. There was a significant difference in the distribution of fungal isolates at P=0.042.The indoor temperature and humidity of Enugu and Nsukka were the same at P using ANOVA, when compared with the hostels that served as control. Considering the public health effects of these airborne fungi, appropriate measures should be put in place in prison indoor environment to prevent the growth of moulds and yeast and its dissemination.

On the airborne transmission of SARS-CoV-2 and relationship with indoor conditions at a hospital

The limited knowledge about the mechanism of SARS-CoV-2 transmission is a current challenge on a global scale. Among possible transmission routes, air transfer of the virus is thought to be prominent. To investigate this further, measurements were conducted at Razi hospital in Ahvaz, Iran, which was selected to treat COVID-19 severe cases in the Khuzestan province. Passive and active sampling methods were employed and compared with regard to their efficiency for collection of airborne SARS-COV-2 virus particles. Fifty one indoor air samples were collected in two areas, with distances of less than or equal to 1 m (patient room) and more than 3 m away (hallway and nurse station) from patient beds. A simulation method was used to obtain the virus load released by a regularly breathing or coughing individual including a range of microdroplet emissions. Using real-time reverse transcription polymerase chain reaction (RT-PCR), 11.76% (N = 6) of all indoor air samples (N = 51) collected in the COVID-19 ward tested positive for SARS-CoV-2 virus, including 4 cases in patient rooms and 2 cases in the hallway. Also, 5 of the 6 positive cases were confirmed using active sampling methods with only 1 based on passive sampling. The results support airborne transmission of SARS-CoV-2 bioaerosols in indoor air. Multivariate analysis showed that among 15 parameters studied, the highest correlations with PCR results were obtained for temperature, relative humidity, PM levels, and presence of an air cleaner.

An alternative generic subslab soil gas-to-indoor air attenuation factor for application in commercial, industrial, and other nonresidential settings

ABSTRACT The default subslab soil gas (SSSG)-to-indoor air attenuation factor (AF) of 0.03 to assess the vapor intrusion (VI) pathway and generate VI screening levels for SSSG was developed by the United States Environmental Protection Agency (EPA) based on chlorinated volatile organic compound (VOC) indoor air and SSSG data collected in residential buildings and compiled in EPA’s 2012 VI database. In their VI guidance published in 2015, EPA recognized that this default AF may be overly conservative for nonresidential buildings. In 2015, the Department of Defense (DoD) began developing a first-of-its-kind VI database to assess AFs at commercial and industrial buildings at DoD installations and support the development of alternative generic AF values. This database was expanded in 2019 to include 76 buildings at 22 DoD installations across the United States and is comparable in size to EPA’s VI database. The DoD database includes chlorinated VOC data from SSSG and indoor air samples collected from multiple sampling zones within these buildings. Empirical SSSG-to-indoor air AFs were calculated using the same screening methods employed by EPA to filter out potential background source contributions unrelated to VI, including a source strength screen. Analysis of indoor air–SSSG data pairs found that there is substantially more attenuation occurring from SSSG to indoor air in DoD commercial and industrial buildings relative to residential buildings, and that the DoD buildings’ AFs are one to three orders of magnitude lower than EPA’s residential-based default of 0.03. The results support the use of a generic SSSG-to-indoor air AF of 10−3 (0.001) to support VI assessment and develop SSSG screening levels at large commercial and industrial buildings as an alternative to the residential default AF. Implications: The use of subslab soil gas (SSSG)-to-indoor air attenuation factors (AFs) is a key component of vapor intrusion (VI) pathway assessments and VI screening level development for SSSG. Currently, the United States Environmental Protection Agency (EPA) and many state regulatory agencies use a default AF of 0.03 based on chlorinated volatile organic compound (VOC) data collected in residential buildings. VI assessment data collected at Department of Defense (DoD) installations indicate that there is significantly more SSSG-to-indoor air attenuation occurring at DoD commercial and industrial buildings. For that reason, the default AF of 0.03 results in SSSG screening levels that are overestimating VI-related risks in these types of building. The DoD data support the use of a generic SSSG-to-indoor air AF of 10−3 (0.001) for conducting VI assessment and developing SSSG screening levels at large commercial and industrial buildings as an alternative to the residential default AF.

Assessment of bio-contaminants during COVID-19 outbreak from the indoor environment of Hail city, Kingdom of Saudi Arabia.

Biocontaminants are minute particles derived from different biological materials. Indoor biocontaminants are associated with major public health problems. In Gulf countries, it is more precarious due to the harsh climatic conditions, including high ambient temperatures and relative humidity. In addition, due to COVID-19 pandemic, most of the time public is inside their home. Therefore, the aim of the study was to determine the load of biocontaminants in the indoor environment of Hail city. The results showed that most of the bacteria are gram-positive and higher in polymicrobial (87.1%) than monomicrobial (62.7%) association. There was no significant association with sample collection time and types of isolates. The most abundant microbes found in all samples were Staphylococcus aureus followed by Bacillus spp. Among Gram-negative bacterial isolates, E. coli was most common in tested indoor air samples. The study will be useful to find the biocontaminants associated with risk factors and their impact on human health in indoor environment, especially during the COVID-19 pandemic. These results indicate the need to implement health care awareness programs in the region to improve indoor air quality.

Compact Formaldehyde Detector Based on Filter–Sensor System with Validated Performance in Indoor Air

Introduction Formaldehyde is a carcinogenic indoor air pollutant emitted from wood-based furniture, building materials, paints and textiles.[1] Yet, no low-cost sensor exists for on-site monitoring to fulfill stringent current and upcoming (e.g., 8 parts-per-billion by volume, ppb, in France by 2023) exposure guidelines. Here, we present an inexpensive and handheld formaldehyde detector with proven performance in real indoor air. Selectivity is achieved by a compact packed bed column of nanoporous polymer sorbent that separates formaldehyde from interferants present in ambient air. Downstream, a highly sensitive nanoparticle-based chemoresistive Pd-doped SnO2 sensor detects formaldehyde in the relevant concentration range down to 5 ppb within 2 min. Method The handheld formaldehyde detector consists of a separation column and a chemoresistive microsensor [2]. The Separation column consists of a packed bed of Tenax TA powder (500 mg poly(2,6-diphenyl-p-phenylene oxide), 60–80 mesh, ~35 m2 g-1, Sigma-Aldrich) packed inside a Teflon tube (4 mm inner diameters) and secured on both ends with silanized glass wool plugs [3]. The sensor is based on a Pd-doped SnO2 nanoparticle film prepared by flame spray pyrolysis (FSP) and directly deposited onto microsensor substrates [4]. The measurement of emissions from wood products was based on standard testing protocol EN-717-1 to ensure comparable results. Measurements with room air were performed by exposing the detector directly to air from the laboratory. To also test higher concentration, room air was spiked with additional formaldehyde from the gas standard on a dynamic gas mixing setup. Results and Conclusions The concept of the formaldehyde detector is illustrated in Figure 1a–c. Indoor air contains >250 different analytes that are separated by a packed bed separation column of commercial Tenax TA particles. Tenax TA offers a high surface area (25 m2 g-1) due to its macroporous structure (Type II adsorption isotherm, Figure 1d) with a volume-average pore size of 120 nm (inset in Figure 1d). This enables efficient adsorption and retention of analytes, similar to a gas chromatographic column, though much more compact (13 cm length), inexpensive (˂ $20 for the Tenax TA powder) and without the need for column heating. After the column, formaldehyde is detected separately from interferants (e.g., hydrogen, methanol), thus selectively, by a highly sensitive but non-specific chemoresistive microsensor (Figure 1e). It consists of a highly porous film of flame-made and directly deposited Pd-doped SnO2 nanoparticles (Figure 1f) that form fine networks with large surface area (54.5 m2 g-1) for formaldehyde detection down to 5 ppb..We validated this detector on real indoor air samples from our laboratory (Figure 2a). First, it shows a large response from non-retained compounds that might be CH4, CO and H2. These gases are all usually present at hundreds of ppb in indoor air. Thereafter, a smaller peak is detected (SNR >40, see inset) at 107 s corresponding to formaldehyde at 45 ppb according to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS). It is not interfered by methanol and ethanol, which are both eluted later, in line with synthetic gas mixtures. Figure 2b shows the scatter plot of the formaldehyde concentration measured by the detector and PTR-TOF-MS for pristine (squares, measured on two different days) and formaldehyde-spiked indoor air (circles) in the range of 14–475 ppb. Both instruments show excellent agreement with an R2 of 0.996, despite the challenging lab environment with high and varying background concentrations of acetone (up to 1,000 ppb) and ethanol (up to 4,000 ppb). Most importantly, the detector shows a low average error of only 10 ppb and can clearly differentiate safe levels from such above the WHO guideline (dashed line) and when immediate sensory irritation (dotted line) occurs.As a result, based on its compact size and low price, this device is promising for monitoring of formaldehyde in indoor air. When interconnected, such next-generation low-cost detectors could enable distributed chemical recognition (Figure 2c) for air quality in “smart” buildings and “future” cities [5].

Assessment of internal exposure to methylsiloxanes in children and associated non-dietary exposure risk

Methylsiloxanes (MSs) are a significant source of indoor environmental pollution due to their high production level and widespread application, and pose a potential health risk. Given the special vulnerability of children to environmental contaminants, assessment of indoor MSs exposure in children is quite essential. In this study, we assessed internal exposure doses and external exposure levels of MSs in children from industrial and residential areas in southwestern China. Indoor air, indoor dust, and personal care product (PCP) samples were collected to evaluate indoor non-dietary MSs exposure in children through various pathways. The concentrations of MSs in indoor environments of industrial areas were approximately one to four orders of magnitude higher than those of residential areas. Sun protection products contained the highest concentrations of MSs. Relatively high levels of cyclic methylsiloxanes (CMSs) were found in plasma of children from industrial areas, which were one to two orders of magnitude higher than those in children from residential areas. The highest MSs levels in plasma were detected in infants (0–1 year), with values of 1.4 × 102 ng/mL and 1.3 × 102 ng/mL for CMSs (D4–D6) and linear methylsiloxanes (LMSs) (L5–L16), respectively. The internal exposure dose of infants in residential areas is driven by major unknown sources of MSs. The average daily doses via inhalation and dust ingestion in children from industrial areas were one to three orders of magnitude higher than in those from residential areas, indicating that these children should be considered a highly exposed population. Inhalation and dust ingestion were both major exposure pathways to MSs for children of all age groups in industrial areas, whereas dermal absorption from PCPs was the predominant exposure pathway for children of all age groups in residential areas (except for infants). Although the exposure risk to D4 and D5 was at an acceptable level for all children studied, the total daily exposure doses of these two cyclic compounds via inhalation for infants in the industrial areas was near the chronic reference dose. Meanwhile, MSs may accumulate in infant plasma within a short period of time (<6 months). Therefore, infants should be the focus of greater attention in future research. As indoor environments may pose high risks for infants in industrial areas, they should be the focus of future research.

Characterization and health risk assessment of particulate bound polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor atmosphere of Central East India.

The selected 16 high-priority polycyclic aromatic hydrocarbons (PAHs) were characterized in PM2.5 in the indoor and outdoor air samples collected at the urban slum and rural sites in the Central East India. At the urban slum site, the indoor and outdoor concentrations of PAHs were 466.03± 11.94 ng/m3 and 321.71± 34.87 ng/m3, respectively. At the rural location, the indoor and outdoor concentrations were 294.85± 20.53 ng/m3 and 241.74± 29.04 ng/m3, respectively. Three-four and five-ring PAHs were found to be dominant in both urban slum and rural sites. Diagnostic ratio (DR) analysis and principal component analysis (PCA) conclude that diesel exhaust, gasoline, biomass, and coal combustion were the significant sources of 16 PAHs in indoor and outdoor environments, the urban slum and rural sites. Lifetime average daily dose (LADD) and incremental lifetime cancer risk (ILCR) values were calculated for health risk assessment for 6-year-old children and 24-year-old adults. The ELCR values in the urban slum site and the rural location were calculated 43.24 × 10-6 and 28.3 × 10-6. The ELCR values were observed between the acceptable limit 10-6-10-4 given by regulatory agency USEPA United States Environmental Protection Agency (1989).

Modeling aerosol transmission of SARS-CoV-2 from human-exhaled particles in a hospital ward.

The COVID-19 pandemic has plunged the world into uncharted territory, leaving people feeling helpless in the face of an invisible threat of unknown duration that could adversely impact the national economic growths. According to the World Health Organization (WHO), the SARS-CoV-2 spreads primarily through droplets of saliva or discharge from the mouth or nose when an infected person coughs or sneezes. However, the transmission of the SARS-CoV-2 through aerosols remains unclear. In this study, computational fluid dynamic (CFD) is used to complement the investigation of the SARS-CoV-2 transmission through aerosol. The Lagrangian particle tracking method was used to analyze the dispersion of the exhaled particles from a SARS-CoV-2-positive patient under different exhale activities and different flow rates of chilled (cooling) air supply. Air sampling of the SARS-CoV-2 patient ward was conducted for 48-h measurement intervals to collect the indoor air sample for particulate with diameter less than 2.5 μm. Then, the reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was conducted to analyze the collected air sample. The simulation demonstrated that the aerosol transmission of the SARS-CoV-2 virus in an enclosed room (such as a hospital ward) is highly possible.

Molecular detection of SARS-CoV-2 from indoor air samples in environmental monitoring needs adequate temporal coverage and infectivity assessment

The relevance of airborne exposure to SARS-CoV-2 in indoor environments is a matter of research and debate, with special importance for healthcare low-risk settings. Experimental approaches to the bioaerosol sampling are neither standardized nor optimized yet, leading in some cases to limited representativity of the temporal and spatial variability of viral presence in aerosols. Airborne viral viability moreover needs to be assessed. A study has been conducted collecting five 24-h PM10 samples in a COVID-19 geriatric ward in late June 2020, and detecting E and RdRp genes by RT-qPCR with a Ct between 36 and 39. The viral RNA detection at Ct = 36 was related to the maximal numerosity of infected patients hosted in the ward. Lacking a direct infectivity assessment for the collected samples an experimental model has been defined, by seeding twelve nasopharyngeal swab extracts from COVID-19 positive patients on Vero E6 cells; only the four extracts with a viral load above E+10 viral copies (approximately Ct<24) have been able to establish a persistent infection in vitro. Therefore, the cytopathic effect, a key feature of residual infectivity, could be considered unlikely for the environmental PM10 samples showing amplification of viral RNA at Ct = 36 or higher. A standardization of airborne SARS-CoV-2 long-term monitoring and of environmental infectivity assessment is urgently needed.

Simultaneous monitoring of SARS-CoV-2, bacteria, and fungi in indoor air of hospital: a study on Hajar Hospital in Shahrekord, Iran.

The novel SARS-CoV-2 outbreak was declared as pandemic by the World Health Organization (WHO) on March 11, 2020. Understanding the airborne route of SARS-CoV-2 transmission is essential for infection prevention and control. In this study, a total of 107 indoor air samples (45 SARS-CoV-2, 62 bacteria, and fungi) were collected from different wards of the Hajar Hospital in Shahrekord, Iran. Simultaneously, bacterial and fungal samples were also collected from the ambient air of hospital yard. Overall, 6 positive air samples were detected in the infectious 1 and infectious 2 wards, intensive care unit (ICU), computed tomography (CT) scan, respiratory patients’ clinic, and personal protective equipment (PPE) room. Also, airborne bacteria and fungi were simultaneously detected in the various wards of the hospital with concentrations ranging from 14 to 106 CFU m−3 and 18 to 141 CFU m−3, respectively. The highest mean concentrations of bacteria and fungi were observed in respiratory patients’ clinics and ICU wards, respectively. Significant correlation (p < 0.05) was found between airborne bacterial concentration and the presence of SARS-CoV-2, while no significant correlation was found between fungi concentration and the virus presence. This study provided an additional evidence about the presence of SARS-CoV-2 in the indoor air of a hospital that admitted COVID-19 patients. Moreover, it was revealed that the monitoring of microbial quality of indoor air in such hospitals is very important, especially during the COVID-19 pandemic, for controlling the nosocomial infections.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-13628-9.

Exposure to phthalates and correlations with phthalates in dust and air in South China homes

We spend more than half of our daily time in indoor environments, and the contributions of phthalates present in it to total exposure are important. Here, we determined phthalate concentrations in paired indoor settled dust/air and their metabolites in human urine from 100 general families in south China to explore such kind of effect. The total concentrations of phthalates/metabolites were 48.7–2850 μg/g, 279–5080 ng/m3 and 10.7–2840 ng/mL in the indoor dust, air and urine samples, respectively. Among all targets, di-n-butyl phthalate, di-isobutyl phthalate and di-(2-ethylhexyl) phthalate and their metabolites were the predominant compounds. The daily intakes (DIs) of phthalates via dust or air decreased with age, except for infant, and the values of dust ingestion, air inhalation and air dermal uptake were 2720 ± 2460, 1300 ± 973 and 3590 ± 2890 ng/kg/day for toddlers and 236 ± 194, 360 ± 179 and 1120 ± 586 ng/kg/day for adults, respectively. The ratios of DIs from air to dust were greater than 1.0 for people in all age groups, and the ratio was the highest for adults. Furthermore, the contributions of phthalates from indoor dust and air to total DIs from all sources (estimated from urinary phthalate metabolites) were 0.60%–5.23% and 2.65%–12.2% for different ages, respectively. Our results indicated that indoor air was a quite important source for human exposure to phthalates in indoor environment in south China.

Ambient and Indoor PM10 and PM10-bound PAHs around the Vicinity of an Industrial Estate in Rayong, Thailand: Concentration and Source Identification

The ambient and indoor air concentrations of PM10 and PM10-bound PAHs (16 priority PAHs) were investigated in Rayong Province, Thailand. The locations of the selected study areas were Map Ta Phut Industrial Estate and its vicinity comprising six sampling sites (four industrial areas and two vicinity areas). The indoor and ambient air samples of were collected in March 2017. The sampling sites located close to the road were detected the greatest ambient average concentrations of PM10, with an average value of 56.06 µg m-3 (Map Chalut Area or MC). The levels of indoor PM10 were mostly dependent on the resident activities and the highest mean level of PM10 was 31.29 µg m-3 detected at Huai Pong. The Benzo(b)fluoranthene and acenaphthylene were the major PAHs found to have the highest 24-h average concentrations for both indoor and ambient air. The highest mean ambient and indoor air levels of benzo(b)fluoranthene were 49.18 and 30.88 ng m-3, respectively, found at MC. In terms of 16 total PAHs, MC was found to have the greatest level. Analysis of the diagnostic ratios determined that the traffic density was the major source of influence on particle-bound PAH concentrations for both ambient and indoor air samples, which indicated that the greater the traffic volume, the higher the level of PAHs.