Ultrasonic humidifier aerosols: Observed high heavy metal enrichment and a new emission control method.

Ultrasonic humidifiers are commonly used in households to maintain indoor humidity and generate a large number of droplets or spray aerosols. However, there have been various health concerns associated with humidifier use, largely due to aerosols generated during operation. Here, we investigated the size distribution, chemical composition, and charged fraction of aerosol particles emitted from commercial ultrasonic humidifiers. Heavy metals in water used for humidifiers were found to be highly enriched in the ultrasonic humidifier aerosols (UHA), with the enrichment factors ranging from 102 to 107. This enrichment may pose health concerns for the building occupants, as UHA concentrations of up to 106 particles/cm3 or 3 mg/m3 were observed. Furthermore, approximately 90% of UHA were observed to be electrically charged, for the first time according to our knowledge. Based on this discovery, we proposed and tested a new method to remove UHA by using a simple electrical field. The designed electrical field in this work can efficiently remove 81.4% of UHA. Therefore, applying this electrical field could be an effective method to significantly reduce the health risks by UHA.

Hunting for a viral proxy in bioaerosols of swine buildings using molecular detection and metagenomics.

There are limited biosecurity measures directed at preventing airborne transmission of viruses in swine. The effectiveness of dust mitigation strategies such as oil sprinkling, to decrease risk of airborne virus transmission are unknown. Metagenomics and qPCR for common fecal viruses were used to hunt for a ubiquitous virus to serve as a proxy when evaluating the efficiency of mitigation strategies against airborne viral infectious agents. Air particles were collected from swine buildings using high-volume air samplers. Extracted DNA and RNA were used to perform specific RT-qPCR and qPCR and analyzed by high-throughput sequencing. Porcine astroviruses group 2 were common (from 102 to 105 genomic copies per cubic meter of air or gc/m3, 93% positivity) while no norovirus genogroup II was recovered from air samples. Porcine torque teno sus virus were detected by qPCR in low concentrations (from 101 to 102 gc/m3, 47% positivity). Among the identified viral families by metagenomics analysis, Herelleviridae, Microviridae, Myoviridae, Podoviridae, and Siphoviridae were dominant. The phage vB_AviM_AVP of Aerococcus was present in all air samples and a newly designed qPCR revealed between 101 and 105 gc/m3 among the samples taken for the present study (97% positivity) and banked samples from 5- and 15-year old studies (89% positivity). According to the present study, both the porcine astrovirus group 2 and the phage vB_AviM_AVP of Aerococcus could be proxy for airborne viruses of swine buildings.

Emission characteristics and probabilistic health risk of volatile organic compounds from leather sofa.

Furniture is identified as a vital volatile organic compound (VOC) emission source in the indoor environment. Leather has become the most common raw and auxiliary fabric material for upholstered furniture, particularly with extensive consumption in sofas, due to its abundant resources and efficient functions. Despite being widely traded across the world, little research has been conducted on the VOCs released by leather materials and their health risk assessment in the indoor environment. Accordingly, this study investigated the VOC emissions of leather with different grades and the health risk of the inhalation exposure. Based on the ultra-fast gas phase electronic nose (EN) and GC-FID/Qtof, the substantial emissions of aliphatic aldehyde ketones (Aks), particularly hexanal, appear to be the cause of off-flavor in medium and low grade (MG and LG) sofa leathers. The health risk assessment indicated that leather materials barely pose non-carcinogenic and carcinogenic effects to residents. Given the abundance of VOC sources and the accumulation of health risks in the indoor environment, more stringent specifications concerning qualitative and quantitative content should be extended to provide VOC treatment basic for the manufacturing industry and obtain better indoor air quality.

Health at Home: Investigating Low-Income Housing Quality on Colfax Avenue.

Addressing housing insecurity contributes to health care programs as stable housing has positive health benefits. Home environmental hazards may reduce these potential health benefits and could increase morbidity for conditions such as asthma. This study examined housing and indoor air quality among urban low-income households in Colorado to inform housing-insecurity interventions. We conducted a community-engaged study among residents of motels, mobile homes, apartments, and single-family homes that included a survey on the home environment, health, and sociodemographic factors, spirometry, and indoor air quality measurement. We enrolled 60 households: 50% single-family homes, 37% apartments, and 13% residential motels. Perceived stress and depression were higher among motel residents compared with other housing types. We did not find differences in lung function by housing type. Indoor fine particulate matter (PM2.5) and black carbon concentrations were higher in motels than in other housing types. The differential health impacts of housing type support housing programs that jointly address security and quality.

Determination of personal exposure to volatile organic compounds and their health risks after the use of mosquito repellents in residential environments using passive sampling.

The ubiquitous use of mosquito repellents in homes across Asia, Africa, and South America is related with human exposure to indoor volatile organic compounds (VOCs). There are three primary types of mosquito repellents: those in the form of coils, mats, and liquids. The repellent mechanisms of these products are distinct, resulting in the generation of varying types of VOCs during the repellent process. In this study, the emission characteristics of commercial coil-, mat-, and liquid-type mosquito repellents were observed in a laboratory chamber using real-time measurement. A previously developed personal passive sampler, ePTFE PS, was used to quantify personal exposure to indoor VOCs while 86 volunteers habitually used those three representative types for 3 h in their residence. Notable increase of indoor benzene was observed for coil- and mat-type mosquito repellents, while α-pinene concentration increased significantly following the use of liquid-type mosquito repellent. The average incremental cancer risks for benzene were 10-6 to 10-4 for adults following the use of coil- and mat-type mosquito repellents. The average non-cancer risks for all chemicals were <1 after the use of three types of mosquito repellents. Considering the potential human health risks associated with byproducts (e.g., particulate matter or carbon monoxide from incomplete combustion) emitted after mosquito coil use, further research on this topic is warranted.

Quantitative and qualitative assessment of airborne microorganisms during gross anatomical class and the bacterial and fungal load on formalin-embalmed corpses.

Mold growth on body donations remains an underreported yet serious issue in anatomical teaching. Bacterial and fungal growth pose health risks to lecturers and students, alongside with ethical and aesthetic concerns. However, limited information exists on the presence of bacteria and fungi on body donations and their underlying causes. To investigate the potential impact of airborne germs on body donation contamination, we conducted indoor air measurements before, during, and after our anatomical dissection course, with outdoor measurements serving as a control. Tissue samples from the dissected body donations were collected to assess the germ load, with qualitative and quantitative microbiological analyses. Air samples from the dissection hall contained no fungi, but various fungal species were identified in the adjacent stairways and outdoors which implies that fungal occurrence in the dissection hall air was independent of lecturers' and students' presence. Moreover, our results indicate that adequate ventilation filters can effectively reduce indoor fungal germs during courses, while the bacterial load in room air appears to increase, likely due to the presence of lecturers and students. Additionally, the tissue samples revealed no bacterial or fungal germs which implies that our ethanol-formalin-based embalming solution demonstrates an effective long-term antimicrobial preservation of corpses.

Intermittent low-dose far-UVC irradiation inhibits growth of common mold below threshold limit value.

Mold infestations in buildings pose significant challenges to human health, affecting both private residences and hospitals. While molds commonly trigger asthma and allergies in the immunocompetent, they can cause life-threatening diseases in the immunocompromised. Currently, there is an unmet need for new strategies to reduce or prevent mold infestations. Far-UVC technology can inactivate microorganisms while remaining safe for humans. This study investigates the inhibitory efficacy of far-UVC light at 222 nm on the growth of common mold-producing fungi, specifically Penicillium candidum, when delivered in low-dose on-off duty cycles, a configuration consistent with its use in real-world settings. The inhibitory effect of the low-dose duty cycles was assessed on growth induced by i) an adjacent spore-producing P. candidum donor and ii) P. candidum spores seeded directly onto agar plates. In both setups, the far-UVC light significantly inhibited both vertical and horizontal growth of P. candidum, even when the UV doses were below the Threshold Value Limit of 23 mJ/cm2. These results suggest that far-UVC light holds the potential to improve indoor air quality by reducing or preventing mold growth, also when people are present.

[Analysis of allergen distribution and indoor factors in allergic rhinitis in Chaoshan area].

Objective:To investigate the distribution of common allergens and indoor factors influencing the severity of allergic rhinitis in patients from the Chaoshan region. Methods:Patients diagnosed with allergic rhinitis from Shantou, Jieyang, and Chaozhou were selected for serum allergen-specific IgE testing. A questionnaire survey was conducted to analyze the distribution of allergens and indoor factors affecting the severity of the disease. Results:A total of 1 800 questionnaires were collected, with 1 646 valid responses, resulting in an effective response rate of 91.4%. Among the 1 646 included patients with allergic rhinitis, there were 1 285 children（≤14 years） ，361 adolescents and adults（>14 years）；of which 999 were males and 647 were females. The top three allergens with the highest positive rates were house dust mites（n=1 457, 88.5%）, milk（n=569, 34.6%）, and crab（n=360, 21.9%）. The proportions of allergen sensitization to house dust mites, house dust, dog dander, egg white, milk, fish, crab, shrimp, and beef showed statistically significant differences between children and adolescents and adults（P<0.01）. There were also statistically significant differences in crab and shrimp sensitization between males and females（P<0.01）. Multivariate analysis revealed that active/passive smoking, religious rituals, air conditioning usage, pet ownership, air purifier usage, and bedding drying were indoor factors influencing the severity of allergic rhinitis. Among them, active/passive smoking, religious rituals, air conditioning usage, and pet ownership were risk factors for exacerbating the disease, while air purifier usage and bedding drying were protective factors. Conclusion:House dust mites are the most common allergen in patients with allergic rhinitis in the Chaoshan region. Active/passive smoking, religious rituals, air conditioning usage, and pet ownership can worsen the condition, while air purifier usage and bedding drying can help control the disease. The results of this study can provide clinical reference.

Surveillance of respiratory viruses by aerosol screening in indoor air as an early warning system for epidemics.

The development of effective methods for the surveillance of seasonal respiratory viruses is required for the timely management of outbreaks. We aimed to survey Influenza-A, Influenza-B, RSV-A, Rhinovirus and SARS-CoV-2 surveillance in a tertiary hospital and a campus over 5 months. The effectiveness of air screening as an early warning system for respiratory viruses was evaluated in correlation with respiratory tract panel test results. The overall viral positivity was higher on the campus than in the hospital (55.0% vs. 38.0%). Influenza A was the most prevalent pathogen in both locations. There were two influenza peaks (42nd and 49th weeks) in the hospital air, and a delayed peak was detected on campus in the 1st-week of January. Panel tests indicated a high rate of Influenza A in late December. RSV-A-positivity was higher on the campus than the hospital (21.6% vs. 7.4%). Moreover, we detected two RSV-A peaks in the campus air (48th and 51st weeks) but only one peak in the hospital and panel tests (week 49). Although rhinovirus was the most common pathogen in panel tests, rhinovirus positivity was low in air samples. The air screening for Influenza-B and SARS-Cov-2 revealed comparable positivity rates with panel tests. Air screening can be integrated into surveillance programs to support infection control programs for potential epidemics of respiratory virus infections except for rhinoviruses.

Health and environmental risk assessment of mercury in outdoor and indoor dust in artisanal and small-scale gold mining area in Amansie-west district in the Ashanti Region of Ghana.

Mercury (Hg) pollution around artisanal and small-scale gold mining (ASGM) areas has been of much concern. Many studies have reported elevated Hg concentrations in environmental media, but studies on dust relating to inhalation exposure of Hg around ASGM area are limited. In this study, we investigated Hg in indoor and outdoor dust to reveal environmental and human health risk around ASGM in Amansie West district, Ghana. Indoor and outdoor dust samples were collected from Manso Abore and Manso Nkwanta in Ashanti Region. Concentration of Hg in the samples were analyzed using a direct Hg analyzer. The mean and median value of Hg concentration in the indoor dust (n = 31) were 2.2 ± 3.6 mg/kg and 0.72 mg/kg respectively while that of the outdoor dust (n = 60) were 0.19 ± 0.48 mg/kg and 0.042 mg/kg, respectively. The mean and median Hg concentration in indoor dust were about 11 and 17 times higher respectively than that in the outdoor dust. The Hg concentration in the indoor dust was statistically significantly higher than that of the non-miner in Manso Abore (p < 0.05) but was not significant in Manso Nkwanta, probably due to higher mining activity. The geo-accumulation index of the outdoor dust ranged from unpolluted to extremely polluted while that of the indoor dust ranged from moderately polluted to extremely polluted. Health risk assessments suggested that there was no potential non-carcinogenic health effect for Hg exposure relating to the dust to residents living in rooms of miners and non-miners.

Concentrations, Profiles, and Potential Sources of Liquid Crystal Monomers in Residential Indoor Dust from the United States.

Liquid crystal monomers (LCMs) are biphenyl- or cyclohexane-based organic chemicals used in electronic digital displays, and several of them possess bioaccumulative and toxic properties. Little is known about their occurrence in indoor dust from the United States. We analyzed 60 LCMs in 104 residential indoor dust samples collected from 16 states across the United States. Forty-seven of 60 LCMs were detected in dust samples at a median ∑LCM concentration of 402 ng/g (range: not detected to 4300 ng/g). Trans-4-propylcyclohexyl trans,trans-4'-propylbicyclohexyl-4-carboxylate (MPVBC) and (trans,trans)-4-fluorophenyl 4'-pentyl-[1,1'-bi(cyclohexane)]-4-carboxylate (FPeBC) were frequently detected in dust samples. We investigated potential sources of LCMs in dust by determining concentrations and profiles of these chemicals in smartphone screens, desktop and laptop computer monitors, and displays of other electronic devices and found that profiles in smartphones matched closely with those found in dust. The calculated median daily intake of ∑LCM through dust ingestion was 1.19 ng/kg bw/d for children, whereas that through dermal absorption was 0.18 ng/kg bw/d for adults in the United States.

Assessment of indoor radon concentration in the dwellings of the industrial areas of Kannur District, Kerala.

All organisms on the earth-crest are exposed to natural background radiation since the evolution of the earth, as many environmental matrices such as soil, air, water bodies, vegetation, etc., act as the sources of natural radioactivity. The present study deals with the evaluation of indoor concentration of 222Rn (radon) in different dwellings with various construction materials used for the roof and floor in the industrial sites of Kannur district, Kerala. A pinhole-based dosemeter coupled with LR-115 Solid State Nuclear Track Detector and Direct Radon Progeny Sensor (DRPS) were respectively used for the measurement of indoor radon concentration and equilibrium equivalent concentration of radon. The indoor radon concentrations were found to vary from 102.30 Bqm-3 to 184.75 Bqm-3 and the values were within the recommended limits provided by International Commission on Radiological Protection (ICRP). The annual effective doses and excess lifetime cancer risks were observed in the range of 2.58-4.66 mSvy-1 and 7.68 × 10-3-15.60 × 10-3, respectively, and both exceed the world average values recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000. The study shows that, the houses with marble floors and concrete roofs have comparatively higher values of radon concentration, which indicates the significant contribution of construction materials to the enhanced radiation levels inside the dwellings.

Measurement of indoor radioactivity and dose derived from 222Rn, 220Rn and EECs by using SSNTD based technique.

Alpha flux radiated from 222Rn, 220Rn and progeny is the primary contributor of natural radioactivity to the inhabitants in the ambient atmosphere. The annual indoor 222Rn and 220Rn concentrations were found to be 85 ± 43 and 84 ± 36 Bq m-3, respectively. The estimated annual indoor 222Rn and 220Rn concentration is below to reference value of 100 Bq m-3 suggested by WHO. The calculated annual inhalation dose due to exposure to the alpha flux of 222Rn, 220Rn and their progeny is well below the recommended reference level given by UNSCEAR and ICRP. The data were further checked for normalisation and found that 222Rn and Effective Equilibrium Radon Concentration (EERC) data are not normally distributed.

Study on seasonal variation of radon, thoron, and their progeny levels in indoor environments and their radiological effects on human health.

Indoor radon (222Rn), thoron (220Rn) and their progeny concentrations have been measured in different types of buildings at different locations in different dwellings in different seasons in Hassan city, Karnataka, using time-integrated passive radon dosemeters containing LR-115 Type II solid-state nuclear track detectors. The annual effective dose due to radon and thoron has been estimated. The activity concentrations were observed to be highest in winter and lowest in summer, and the data also shows that bathrooms and kitchens have significantly higher radon-thoron concentrations and annual effective doses.

Ambient gamma radiation level around Kaveri river basin, Karnataka state, India.

Studies on ambient gamma radiation in indoor and outdoor environment and their effect on human health have created interest among the researchers across the world. The present study represents the results of indoor and outdoor ambient gamma dose rates around the Kaveri river basin from Talakaveri (Madikeri district) to Mekedatu (Ramanagara district) by using portable Environmental Radiation Dosemeter. The annual effective dose in the present study area varies between 0.14 mSv.y-1 and 0.58 mSv.y-1 with an average value of 0.30 mSv.y-1 for indoor radiation. The outdoor annual effective dose ranged between 0.01 mSv.y-1 and 0.14 mSv.y-1 with an average value of 0.06 mSv.y-1. The total annual effective dose varies from 0.17 to 0.72 mSv.y-1 with an average value of 0.36 mSv.y-1. The calculated values of indoor and outdoor annual effective dose in the study area (are found to be lower than the world average values (1 mSv.y-1 and 0.48 mSv.y-1).

A study of 222Rn/220Rn exhalation rate and indoor 222Rn/220Rn levels in higher Himalayan terrain.

The noble radioactive gas radon and its isotope thoron dominate terrestrial radiation in the indoor environment. These gases eventually disintegrate generating radioactive ions that readily adhere to aerosol particles. This study was conducted in a tectonically active location with significant radon concentrations. The obtained average values of radon mass exhalation and thoron surface exhalation rate from this study are higher than the global average values of 56 mBq kg-1 h-1 and 1000 mBq m-2 s-1, respectively. As the exhalation rates are higher, naturally the average radon and thoron concentrations are also greater than the worldwide average values of 40 and 10 Bq m-3, respectively. No significant correlation was observed between 222Rn and 220Rn exhalation rate and indoor 222Rn/220Rn concentration. The exposure dose due to 222Rn, 220Rn and their progenies shows no significant health risk.

Impact of secondhand smoke on air quality in partially enclosed outdoor hospitality venues: a review.

BACKGROUND: Smoking is a leading cause of premature mortality and morbidity globally. The pollutants generated from smoke are not only harmful to smokers, but also to those exposed to secondhand smoke. As a result of increasingly restrictive indoor smoke-free policies in many countries, there is a tendency for tobacco smoking to move outdoors into partially enclosed settings in hospitality venues. The aim of this systematic review was to evaluate the impact of secondhand smoke on air quality in outdoor hospitality venues. METHODS: Two electronic databases PubMed and Scopus were searched from 1 January 2010 to 30 June 2022 for studies of air quality impacts from tobacco smoking in outdoor hospitality venues. A total of 625 studies were screened and 13 studies were included in this review. RESULTS: The majority (9 studies) of reviewed studies monitored PM2.5 concentration as an indicator of secondhand smoke. PM2.5 was reported from 10.9 µg/m3 to 91.0 µg/m3 in outdoor smoking areas, compared to 4.0 µg/m3 to 20.4 µg/m3 in outdoor control sites unaffected by smoking. Secondhand smoke can also drift into adjacent outdoor areas or infiltrate into indoor environments thus affecting air quality in spaces where smoking is not permitted. CONCLUSIONS: The reviewed studies indicated that air quality within outdoor hospitality venues where smoking is permitted is unlikely to meet current World Health Organization (WHO) ambient air quality guidelines for PM2.5. Customers and staff in outdoor hospitality venues with active smoking, and in adjacent outdoor and indoor non-smoking areas, are potentially exposed to secondhand smoke at levels exceeding WHO guidelines. Stronger smoking control policies are recommended for outdoor hospitality venues to protect the health of customers and staff from harmful secondhand smoke exposure. PROSPERO REGISTRATION: CRD42022342417.

Polybrominated diphenyl ethers in indoor dust from Brazil: assessing demographic differences and human health exposure.

Indoor house dust is considered an important human exposure route to polybrominated diphenyl ethers (PBDEs), which has raised concern about their environmental persistence and toxicity properties. In this study, eight PBDEs (BDE-28, -47, -99, -100, -153, -154, -183, and -209) were determined in house dust from two cities with different socio-demographic characteristics from Brazil, examining possible relationships with factors that potentially influence contamination (population density, economic activities, presence of electronic equipment, and so on) and also estimating the risk of human exposure through oral ingestion and dermal contact. The Σ8PBDE concentration in Sorocaba city ranged between 380 and 4269 ng/g dw, while in Itapetininga city ranged from 106 to 1000 ng/g dw. In both regions, BDE-209 was the most abundantly found congener, followed by BDE-99. House dust from Sorocaba presented significantly greater concentrations of BDE-183 and BDE-209 than Itapetininga. Regarding risk exposure assessment, the estimated daily intake (EDI) of PBDEs was much lower than their respective reference doses (RfDs) in all pathways estimated (non-dietary ingestion and dermal contact). This study provided valuable data to improve the knowledge about the presence and exposure to PBDEs in Brazilian house dust in comparison to other developing countries and the need to control environmental pollution and protect human health.

Simultaneous indoor radon/thoron and in situ outdoor gamma dose measurements and estimation of annual effective dose in a tin mining area of Jos Plateau, Nigeria.

Radon, a radioactive gas can increase the risk of lung cancer when breathe in. Indoor Rn-222 and Rn-220 concentrations were determined using passive radon monitor in some dwellings in a Sn mining area of Jos Plateau. Outdoor gamma radiation was also measured with a hand-held survey meter. The range of Rn-222 and Rn-220 concentrations was from 7-53 Bq m-3 to 41-267 Bq m-3 with averages of 27 ± 17 and 92 ± 65 Bq m-3, respectively. The mean total effective dose due to Rn-222 + Rn-220 was estimated as 2.84 ± 1.57 mSv y-1. Rn-220 contributed between 50 and 95% to the total annual effective dose. There was no correlation between indoor Rn-220 and Rn-222 concentrations in the dwellings. Outdoor gamma radiation measured was between 0.31 ± 0.06 and 0.62 ± 0.08 µSv h-1, and mean annual effective dose calculated was 1.14 ± 0.21 mSv y-1. It is concluded from this study that thoron should not be neglected in dose assessment.

Concentrations of potentially endocrine disrupting chemicals in car cabin air and dust - Effect of temperature and ventilation.

Materials in car cabins contain performance-enhancing semi-volatile organic compounds (SVOCs). As these SVOCs are not chemically bound to the materials, they can emit from the materials at slow rates to the surrounding, causing human exposure. This study aimed at increasing the understanding on abundance of SVOCs in car cabins by studying 18 potential endocrine disrupting chemicals in car cabin air (gas phase and airborne particles) and dust. We also studied how levels of these chemicals varied by temperature inside the car cabin along with ventilation settings, relevant to human exposure. A positive correlation was observed between temperature and SVOC concentration in both the gas and the particle phase, where average gas phase levels at 80 °C were a factor of 18-16,000 higher than average levels at 25 °C, while average particle phase levels were a factor of 4.6-40,000 higher for the studied substances. This study also showed that levels were below the limit of detection for several SVOCs during realistic driving conditions, i.e., with the ventilation activated. To limit human exposure to SVOCs in car cabins, it is recommended to ventilate a warm car before entering and have the ventilation on during driving, as both temperature and ventilation have a significant impact on SVOC levels.