Indoor Health Risks Research Articles

Predictive Geogenic Radon Potential (P-GRP): A novel approach for comprehensive hazard assessment and risk modeling in subsurface environment

Geogenic radon potential (GRP) is traditionally used for mapping radon-prone areas. However, this has challenges in the accurate assessment of radon risk because of limitations such as oversimplified soil measurements and lack of geological profiles. This study presents predictive geogenic radon potential (P-GRP), integrating geological characterization and advanced modeling for the emanation and transport of radon in the subsurface environment. Seoul, South Korea, was selected as the research area for the evaluation of hazards using P-GRP, while subway station A was selected for the assessment of indoor health risks. The geology was characterized by the layers of bedrock and soil using uranium contents and porosity. The emanation of radon was modeled considering the radioactive decay chain of uranium and the pore structures. The vertical transport of radon was modeled considering the porosity variation within geological media, which was used for the calculation of P-GRP. Without loss of continuity, the P-GRP map was constructed by calculating P-GRP at a specific depth over the Seoul area. The calculation of P-GRP in the case of subway station A demonstrates that the radon concentration in the bedrock at the platform depth was expected to be 382 million Bqm−3. The indoor radon risk was calculated using the P-GRP by coupling the vapor intrusion process. This presented a high cancer risk for the employees as well as commuters. The P-GRP map of Seoul demonstrated higher hazards in granite zones compared to banded gneiss zones. These results have demonstrated that the P-GRP could be a novel and promising approach for assessing hazard and risk by geogenic radon during subsurface development.

Domestic cats as environmental lead sentinels in low-income populations: a One Health pilot study sampling the fur of animals presented to a high-volume spay/neuter clinic.

Non-human animals serve as sentinels for numerous issues affecting humans, including exposure to toxic heavy metals like lead. Lead plays a role in perpetuating cycles of poverty in low-income communities due to the inequitable distributions of indoor health risks from lower-quality housing and outdoor health risks from industry and polluters, compounded by inequitable distributions of heath care and education. In this pilot study, we explore the potential for studying lead in low-income populations by partnering with nonprofit veterinary outreach programs. We investigate the lead concentration in fur samples of 85 domestic cats (Felis catus) presented to a high-volume spay/neuter clinic and report a mean of 0.723 μg of lead per gram of fur. This study reveals new information about lead exposure in cats in the USA, including that females had greater lead exposure than males, lead exposure increased with increasing amount of access to the outdoors, and lead exposure increased in cats with decreased body condition. We propose that pet, feral, and free-roaming cats presented to high-volume spay/neuter clinics could serve as a source of data about lead exposure in disadvantaged communities where these clinics already operate. Such a non-invasive surveillance system using inert, unobtrusively obtained samples could be deployed to detect highly exposed cats, prompting to follow up contact to a cat's caretakers to recommend seeking lead testing for themselves, their families, and their neighbors.

Transport and trajectory of cough-induced bimodal aerosol in an air-conditioned space

Aerosol generated from a human cough can be a potential major indoor health risk due to the possible transmission of infectious respiratory diseases to surrounding individuals within the same room and even could spread out via air-ventilation/conditioning systems. This study aims to investigate the transport characteristics and trajectory of coughed aerosols under the influence of conditioned air ventilation as well as near-by human breathing zone using computational fluid dynamics (CFD). An experimental system consisting of air-conditioned space with multiple inlets and outlets, a cough simulator and a receiver was built to validate the CFD predictions. The comparison is in good agreement. The CFD model was established as a transient three-dimensional multiphase multicomponent Eulerian–Lagrangian model and numerically solved using commercial software ANSYS Fluent. Both gas and liquid phases were modelled as multicomponent mixtures. With this CFD model, the indoor transport and trajectory of coughed aerosols can be accounted for the distributions of portions inhaled by each manikin, deposited on surfaces of manikins and chamber walls, as well as recirculated back into the ventilation system. Results reveal that the aerosol source location and the ambient air movement can be crucial factors of aerosol trajectory in terms of direct and indirect influence.

Field study on indoor health risk factors in households with schoolchildren in south-central China

A field study on indoor thermal environment and pollutants was conducted in 10 households with 10–12 years old children in Changsha, a south-central city in China. The aim is to identify and examine the main indoor pollutants which affect schoolchildren's health. The households were divided into two groups: 1) Group A, households with apparently unhealthy children, 2) Group B, households with healthy children. The findings for autumn and winter indicated that the differences in temperature and relative humidity (RH) between Groups A and B were not significant. The average concentrations of CO2, HCHO and acetaldehyde of Group A were lower than those of Group B. However, the average concentrations of PM2.5 and TVOCs of Group A were higher than those of Group B. In addition, the indoor PM2.5 concentrations in ten households, exceeded the upper limit of the Chinese national standard (75 μg/m3) and the TVOCs concentration in two households exceeded the upper limit (600 μg/m3) in winter. The average concentrations of Di(2-ethylhexyl) Phthalate (DEHP) and Dibutyl Phthalate (DBP) which could harm children's health were significantly higher in the Group A household than those in that of Group B. Cladosporium, Aspergillus and Penicillium in indoor air and house dust which could have lead to children's allergy and respiratory diseases correlated with the seasonal climate variation. It was found that high-level indoor PM2.5, TVOCs, DEHP and DBP in house dust were possibly the main risk factors for children's health, with Cladosporium, Aspergillus and Penicillium possibly providing associated health risks.

Ecofreindly, candle precursor (Paraffin wax) production by Iranian indigenous bacterium to reduce the indoor health risks

The potential indoor air impacts of burning candles have drawn increased attention in recent years. Burning paraffin waxes itself, regardless to wick and the essence, produce some allergens and even carcinogenic compounds. Further biorefining of petroleum paraffin wax with proper bacteria is one of the proposed resolutions to decrease the health threat. Therefore in this study Iranian heavy crude oil sample were screened for the best isolate to reach the target. Manual culture and plate count method and screening were done in MSM medium supplemented with paraffin wax as the sole source of carbon and energy in 40°C and 150rpm. The growth curve of the best isolate was depicted through spectrophotometry during 24 hours. Then the isolate was characterized by biochemical test and molecular identification using 16srRNA. The spore forming, biosurfactant producing bacterium was identified as Bacillus cereus. Gas chromatogaraphs revealed the efficient degradation of long chain paraffin wax with the selected Bacillus cereus into 15 to 25 carbon length n- alkanes. The high physicochemical endurance of this bacterium including salinity tolerance from 0.5to 15 percent, pH from 4 to 10 and temperature growth range from 40 to 65°C, makes it a decent choice for industrial and environmental approaches.

Optimal Trajectory Finding of IDP Ventilation Control with Outdoor Air Information and Indoor Health Risk Index

Optimal Trajectory Finding of IDP Ventilation Control with Outdoor Air Information and Indoor Health Risk Index

Human health risks of petroleum-contaminated groundwater

The volatile organic compounds Benzene, Toluene, Ethylbenzene and Xylene (BTEX) are commonly found in petroleum derivatives and, at relatively high levels, can be associated with human health risks. Due to industrial activities, accidental petroleum spills are the main route of soil and groundwater contamination. The aim of the present study was to evaluate the indoor health risks due to tap water consumption contaminated by BTEX. BTEX indoor exposure can occur through three principal pathways: inhalation, ingestion and dermal absorption. A multiphase and multicomponent model was used to simulate BTEX transport in groundwater. For evaluation of human risks due to the use of contaminated tap water, a mathematical model was elaborated. BTEX concentrations in a drinking well were obtained as a function over time. These concentrations were used to obtain the exposure due to the use of water from the contaminated drinking well. In addition to showing the highest concentration in water, benzene was the compound that remained for a longer period before being completely degraded. For all the evaluated BTEX, oral ingestion was also the main pathway of exposure for adults, whereas the contribution of inhalation and oral exposition in children were seen to be of the same magnitude. The sensitivity analysis of BTEX total dose for adults showed that direct ingestion was the most significant factor, followed by shower time, volume of the shower room, inhalation rate, and shower flow rate. For children, the most significant variable was also direct ingestion, followed by shower time, volume of the shower room, and body weight. In the current design situation, there would not be any health risks by the use of BTEX-contaminated water to the general population living in the neighborhood of the petroleum spill. Therefore, no remediation measures in the area of the spill would be necessary. The present results indicate that the design of a good scenario can perform an accuracy risk assessment. This model can serve as a useful tool for predicting indoor exposure to substances for which no direct data are available, reducing monitoring efforts and observing how different processes affect outcomes. These preliminary data allow the establishment of a basis for further investigations focusing on efficiently recovering petroleum from contaminated sites.

A Comparison Study of Urban and Rural Residents' Indoor Environmental Consciousness during Decoration in Northern China

China still remains a predominantly rural society with 58% of the population currently living in rural areas. Indoor air pollution problems produced during indoor decoration (ID) have been chosen as examples to illustrate new types of pollution problems due to house building and construction in the cadre of New Rural Construction in China. Indoor environmental consciousness is chosen to evaluate the indoor health risk to northern rural Chinese. The awareness of the impact of indoor pollution has been assessed by a comparison between urban and rural residents regarding aspects like attitude, knowledge, and abatement behavior of indoor environmental pollution due to ID. The consumers of decoration materials in Beijing city and Qing County are investigated by questionnaires handed out at random and special interviews in some typical cases. Based on the analysis, the main health risks during ID have been explored, some factors influencing rural people's awareness of indoor pollution are discussed, and some policy suggestions are brought forward.

Survey of Pest Infestation, Asthma, and Allergy in Low-income Housing

Low-income housing often has multiple indoor health risks. Among them, pest infestation, pesticide use, and pest allergens are recognized as common risks which affect residents' health. Cockroach and rodent allergens are associated with morbidity and mortality of asthmatics. To characterize the levels of pest infestation, residents' attitudes toward pest control, and the relationships among cockroaches, mice, cockroach allergen level, asthma and allergy rate in public housing, we interviewed residents from 358 randomly selected apartments in Gary, Indiana and assessed the environmental conditions. Dust samples were collected from 101 apartment kitchen floors to analyze for cockroach allergen (Bla g 1 and Bla g 2) levels. Eighty one percent of the apartments were found infested by cockroaches, mice, ants, spiders, or flies. In the 101 apartments evaluated, 98% of the kitchen dust samples had detectable levels of Bla g 1 allergen (>or=0.4 U/g), 52% had >or=2 U/g, and 33% had >or=8 U/g of Bla g 1. Among the 1,173 residents, 13% and 9% had physician-diagnosed asthma and allergy, respectively. Existence of diagnosed asthmatic was positively correlated with mouse infestations.