Indoor Pollution Research Articles

Indoor air quality analysis and sustainable practices

A constant supply of fresh air is vital for eliminating harmful bacteria and supporting the body's immune system against viruses and infections. Poor indoor air quality poses significant health risks, affecting human well-being and productivity. To address this issue, indoor air quality analysis is essential for enclosed spaces like homes, offices, and schools. According to the United States Environmental Protection Agency, indoor air can be up to 1000 times more polluted than outdoor air, with modern lifestyles leading to people spending 80-90% of their time indoors. Air pollution, as reported by the World Health Organization, causes 7 million deaths annually, primarily affecting the lungs and increasing the risk of cardiovascular diseases. Monitoring indoor air quality parameters such as CO2 and humidity levels is crucial for a healthy lifestyle. By utilizing sensors like MQ135 and DHT11, we can measure indoor pollutants and evaluate ventilation systems' effectiveness. Automation, such as using servo motors for ventilation, helps maintain safe indoor air quality levels. This approach can be implemented across various sectors, including schools, malls, and offices, to create healthier environments. Ultimately, indoor air quality analysis plays a vital role in enhancing indoor air quality and promoting occupant well-being.

Improving indoor air quality and thermal comfort using a total heat exchanger ventilation system for an office building

Indoor air quality (IAQ) and thermal comfort affect occupant comfort and productivity. Thermal comfort supports productivity, while IAQ maintains occupant health. However, occupants are the main source of carbon dioxide, which is the main index for indoor pollutants in educational buildings due to many occupants gathering in one room. This study investigates the performance of applying a total heat exchanger (THX) for diluting carbon dioxide (CO2). Besides, the thermal comfort of the occupants has been evaluated extensively as the THX also reduces the fresh air temperature. An office area with 14 graduate students seated in a meeting was investigated. Questionnaires and field measurements were conducted simultaneously. Time-varying IAQ (carbon dioxide concentration) was assessed using computational fluid dynamics. The numerical simulation program also contained User Defined Function (UDF) based predicted mean vote (PMV) algorithms to determine occupant thermal comfort. The results indicated that without using THX, the CO2 concentration gradually rises until it reaches a maximum of 1400 ppm inside the room. This condition occurs because there is no air change between indoor and fresh air, mainly due to the lack of fresh air supply and reliance on split AC for circulation. With THX, the concentration could lower to below 1000 ppm. In addition, it also could make room temperature slightly lower, with the overall temperature average in this study being 24.5?C without THX and 24.1?C when THX is operated.

Implications of Exposure to Air Pollution on Male Reproduction: The Role of Oxidative Stress.

Air pollution, either from indoor (household) or outdoor (ambient) sources, occurs when there is presence of respirable particles in the form of chemical, physical, or biological agents that modify the natural features of the atmosphere or environment. Today, almost 2.4 billion people are exposed to hazardous levels of indoor pollution, while 99% of the global population breathes air pollutants that exceed the World Health Organization guideline limits. It is not surprising that air pollution is the world's leading environmental cause of diseases and contributes greatly to the global burden of diseases. Upon entry, air pollutants can cause an increase in reactive oxygen species (ROS) production by undergoing oxidation to generate quinones, which further act as oxidizing agents to yield more ROS. Excessive production of ROS can cause oxidative stress, induce lipid peroxidation, enhance the binding of polycyclic aromatic hydrocarbons (PAHs) to their receptors, or bind to PAH to cause DNA strand breaks. The continuous and prolonged exposure to air pollutants is associated with the development or exacerbation of pathologies such as acute or chronic respiratory and cardiovascular diseases, neurodegenerative and skin diseases, and even reduced fertility potential. Males and females contribute to infertility equally, and exposure to air pollutants can negatively affect reproduction. In this review, emphasis will be placed on the implications of exposure to air pollutants on male fertility potential, bringing to light its effects on semen parameters (basic and advanced) and male sexual health. This study will also touch on the clinical implications of air pollution on male reproduction while highlighting the role of oxidative stress.

Volatile organic compounds and respiratory diseases

Our home is a place of refuge and protection, where we spend an average of 80 % of our time. Indoor air quality is an essential element that directly influences the health and well-being of individuals. The main sources of indoor pollution are human activity, which releases not only fine particles and carbon monoxide, but also volatile organic compounds (VOCs). A growing number of studies show a relationship between respiratory pathologies such as chronic obstructive pulmonary disease, asthma or Sick Building Syndrome, and exposure to VOCs. The aim of this article is to explore the relationship between VOCs and respiratory diseases, as well as the strategies to prevent their effect on health.

Quantification and visual inspection of adipic dihydrazide in textile using a xanthylium-based ratiometric fluorescent probe.

Residual adipic dihydrazide (ADH) in textiles may react with formaldehyde to form hydrazone, which is a source of the formaldehyde pollutant indoors. In this paper, a xanthylium-based ratiometric fluorescent probe SH-Py was developed for ADH detection. The emission of SH-Py at 680 nm decreased, whereas that at 463 nm increased upon the addition of ADH in pure DMSO. The LOD was as low as 24.5 nM, and the possible sensing mechanism is presented. Good recoveries were observed in the standard recovery experiments of SH-Py for ADH detection in textiles. Moreover, the visualization of ADH in textiles was successfully achieved by spraying the probe solution and then inspecting it under a UV lamp. Additionally, SH-Py has the potential to quantify other aliphatic hydrazides in various samples.

Techno-economic analysis of a hydrogen fuel cell hybrid system and corresponding optimum matching design for hydrogen fuel cell forklifts

Conventional forklifts face serious issues, with internal combustion engine models causing indoor pollution, and lead-acid battery variants having slow charging and reduced power output as the charge diminishes. To address these drawbacks, this paper introduces a 2.5-tonne fuel cell forklift designed for Hong Kong's bustling logistics, warehousing, and transportation needs. It presents the development of dynamic simulation and cycle condition models, incorporating life cycle cost and average efficiency functions. Simulations reveal that selecting a 50-cell stack (rated at 11.8 kW) is the most cost-effective option, reducing hydrogen consumption by 2.3% using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) optimisation. Cycle conditions do not alter the stack's optimal working voltage. However, the stack's voltage is influenced by stack and hydrogen prices, requiring an optimal design based on Hong Kong's actual costs. This study provides a theoretical foundation for future fuel cell forklift design through techno-economic analysis.

A novel method for assessing indoor di 2-ethylhexyl phthalate (DEHP) contamination and exposure based on dust-phase concentration

Phthalates (PAEs) are a group of typical semivolatile organic compounds that are widely present in indoor environments with multiple phases. Indoor air, airborne particle and settled dust are considered to be typical indicators of PAE contamination as well as media of human exposure, and the interactions between them are complex. Among various phthalate compounds, di 2-ethylhexyl phthalate (DEHP) was identified as the predominant individual phthalate in settled dust. The existing DEHP contamination assessment requires multiphase sampling or solving the dynamic mass transfer models with multiple partial differential equations, which are both complicated and time-consuming. This study investigated the influence of the indoor source loading rate, surface type, particle size and cleaning frequency on the partitioning between the settled dust-phase, airborne particle-phase and gas-phase. The concentration correlations of DEHP between multiphases were consequently derived, which balance accuracy and complexity well. By comparison with field sampling data in the literatures, the rationality and accuracy of the concentration correlations were validated. Based on the concentration correlations, a new method of directly using dust-phase concentration to estimate the non-dietary exposure to DEHP was proposed. The results indicated that ingestion of settled dust contributes the most to non-dietary exposure. Special attention should be given to infants and toddlers, who suffer the highest daily exposure to DEHP among all age groups. This study provides a new and efficient solution for estimating indoor DEHP pollution loads conveniently and rapidly, offering valuable insights for future research in this field.

Study on indoor pollutants emission in Akure, Ondo State, Nigeria

PurposeThis study aimed to characterize the concentrations of indoor pollutants (such as carbon dioxide (CO2), ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2), as well as particulate matter (PM) (PM1, PM2.5 and PM10) in Akure, Nigeria, as well as the relationship between the parameters’ concentrations.Design/methodology/approachThe evaluation, which lasted four months, used a low-cost air sensor that was positioned two meters above the ground. All sensor procedures were correctly carried out.FindingsCO2 (430.34 ppm), NO2 (93.31 ppb), O3 (19.94 ppb), SO2 (40.87 ppb), PM1 (29.31 µg/m3), PM2.5 (43.56 µg/m3), PM10 (50.70 µg/m3), temperature (32.4°C) and relative humidity (50.53%) were the average values obtained. The Pearson correlation depicted the relationships between the pollutants and weather factors. With the exception of April, which had significant SO2 (18%) and low PM10 (49%) contributions, NO2 and PM10 were the most common pollutants in all of the months. The mean air quality index (AQI) for NO2 indicated that the AQI was “moderate” (51–100). In contrast to SO2, whose AQI ranged from “moderate” to “very unhealthy,” O3's AQI ranged from “good” (50) to “unhealthy” (151–200). Since PM1, PM2.5 and PM10 made up the majority of PC1’s contribution, both PM2.5 and PM10 were deemed “hazardous.”Practical implicationsThe practical implication of indoor air pollution is long-term health effects, including heart disease, lung cancer and respiratory diseases such as emphysema. Indoor air pollution can also cause long-term damage to people’s nerves, brain, kidneys, liver and other organs.Originality/valueLack of literature in terms of indoor air quality (IAQ) in Akure, Ondo State. With this work, the information obtained will assist all stakeholders in policy formulation and implementation. Again, the low-cost sensor used is new to this part of the world.

The occurrence, sources, and health risks of substituted polycyclic aromatic hydrocarbons (SPAHs) cannot be ignored

Similar to parent polycyclic aromatic hydrocarbons (PPAHs), substituted PAHs (SPAHs) are prevalent in the environment and harmful to humans. However, they have not received much attention. This study investigated the occurrence, distribution, and sources of 10 PPAHs and 15 SPAHs in soil, water, and indoor and outdoor PM2.5 and dust in high-exposure areas (EAH) near industrial parks and low-exposure areas (EAL) far from industrial parks. PAH pollution in all media was more severe in the EAH than in the EAL. All SPAHs were detected in this study, with alkylated and oxygenated PAHs being predominant. Additionally, 3-OH-BaP and 1-OH-Pyr were detected in all dust samples in this study, and 6-N-Chr, a compound with carcinogenicity 10 times higher than that of BaP, was detected at high levels in all tap water samples. According to the indoor-outdoor ratio, PAHs in indoor PM2.5 in the EAH mainly originated from indoor pollution sources; however, those in the EAL were simultaneously affected by indoor-outdoor air exchange and indoor sources. Most target PAHs tended to deposit from air to dust, and this tendency was significantly negatively associated with the octanol-air partitioning coefficient of PAHs. SPAHs in the environment are primarily derived from the petroleum industry and the mixed combustion of gasoline, biomass, and coal. The toxicity equivalence factors of SPAHs were predicted using QSAR models to assess their lifetime carcinogenic risk (ILCR). The ILCRtotal from PAHs for adults in the EAH was >10−4. Though the levels of 6-N-Chr and 1-Me-Pyr in the environment were markedly lower than those of PPAHs, their ILCRs from PM2.5 inhalation and dermal contact with water exceeded 10−6. This study is significant for recognizing and controlling the health risks associated with SPAHs in humans.

Preconceptional, pregnant, and postnatal exposure to outdoor air pollution and indoor environmental factors: Effects on childhood parasitic infections

BackgroundParasitic infections (PIs) are common and pose substantial health hazards in children globally, but the fundamental environmental variables exposure during crucial time window(s) are unclear. ObjectivesTo identify key indoor and outdoor environmental factors leading to childhood PIs throughout critical time window(s). MethodsA combined cross-sectional and retrospective cohort study was performed on 8689 children residing in Changsha, China. Data was acquired pertaining to the health status and environmental exposure of the children in their homes. Personal exposure to outdoor air pollutants at the residential address during the preconceptional, perinatal, and postnatal periods was computed using data from ten air quality monitoring stations. An analysis of the relationships between childhood PIs and both indoor and outdoor factors was conducted using a multiple logistic regression model. ResultsChildhood PIs were associated with outdoor CO and ozone (O3) exposure during the 10th–12th months prior to pregnancy, with ORs (95 % CI) of 1.68 (1.24–2.27) and 1.60 (1.15–2.22), respectively; childhood PIs were also associated with CO exposure during one year prior to pregnancy and the first trimester in utero [ORs = 1.57 (1.14–2.15) and 1.52 (1.17–1.97)]. Childhood PIs were found to be associated with PM2.5 exposure during pregnancy and the first year, with odds ratios of 1.51 (1.14–2.00) and 1.95 (1.22–3.12) per IQR increase in pollutant exposure, respectively. Exposures to smoke, renovation-related indoor air pollution (IAP), dampness and plant-related indoor allergens in the early life and past year were all associated with childhood PI, with odds ratios (95 % CI) ranging from 1.40 (1.01–1.95) for environmental tobacco smoke (ETS) during pregnancy to 1.63 (1.12–2.37) for mold/damp stains in the past year. In terms of PI risk, the early life and present periods were critical time windows for outdoor and indoor exposures, respectively. Certain individuals were more vulnerable to the PI risk associated with both indoor and outdoor exposures. Antibiotic use during child's lifetime and early years increased and decreased the PI risk of exposure to outdoor and indoor environments, respectively. ConclusionsExposure to outdoor air pollution in early life and indoor environments in the past year were found to be associated with childhood PI.

Modulation of gene expression and influence of gene polymorphisms related to genotoxicity and redox status on occupational exposure to inhaled anesthetics

The extensive use of inhalational anesthetics contributes to both indoor and outdoor (environmental) pollution. The influence of genetic susceptibility on DNA damage and oxidative stress and the possible modulation of gene expression have not yet been investigated upon occupational exposure to waste anesthetic gases (WAGs). This study assessed 8-oxoguanine DNA glycosylase 1 (OGG1) and superoxide dismutase 2 (SOD2) gene expression, which are related to oxidized DNA repair and antioxidant capacity, respectively, and the influence of their polymorphisms (OGG1 rs1052133 and SOD2 rs4880) in 100 professionals highly exposed to WAGs and 93 unexposed volunteers (control group). Additionally, X-ray repair cross complementing 1 (XRCC1 rs25487 and rs1799782) and ataxia telangiectasia mutated (ATM rs600931) gene polymorphisms as well as genetic instability (micronucleus-MN and nuclear bud-NBUD) and oxidative stress (malondialdehyde-MDA and ferric reducing antioxidant power-FRAP) biomarkers were assessed in the groups (control and exposed) and in the subgroups of the exposed group according to job occupation (anesthesiologists versus surgeons/technicians). Except for the ATM TT controls (associated with increased FRAP), there were no influences of OGG1, XRCC1, ATM, and SOD2 polymorphisms on MN, NBUD, MDA, and FRAP values in exposed or control subjects. No significant difference in the expression of either gene evaluated (OGG1 and SOD2) was found between the exposed and control groups. Increased OGG1 expression was observed among OGG1 -/Cys individuals only in the control group. Among the exposed group, anesthesiologists had a greater duration of WAG exposure (both h/week and years) than surgeons/technicians, which was associated with increased MDA and decreased antioxidant capacity (FRAP) and SOD2 expression (redox status). Higher expression of OGG1 was found in -/Cys surgeons/technicians than in anesthesiologists with the same genotype. Increased antioxidant capacity was noted in the surgeons/technicians carrying the ATM T allele and in those carrying XRCC1 -/Gln. Increased MN was influenced by OGG1 -/Cys in surgeons/technicians. Anesthesiologists with ATM CC exhibited increased MN, and those carrying the C allele (CC/CT genotype) exhibited increased NBUD. SOD2 polymorphism did not seem to be relevant for WAG exposure. These findings contribute to advancing the knowledge on genetic susceptibility/gene expression/genetic instability/oxidative stress, including differences in job occupation considering the workload, in response to occupational exposure to WAGs.

Indoor particulate matter concentrations and air cleaner intervention association with biomarkers in former smokers with COPD

BackgroundIndoor pollutants have been associated with worse clinical outcomes in chronic obstructive pulmonary disease (COPD). Elevated biomarkers are associated with ambient pollution exposure, however the association with indoor pollution remains unclear. MethodsFormer smokers with spirometry-confirmed COPD were randomized to portable air cleaner or placebo. Indoor particulate matter (PM2.5, PM10, and ultrafine particles [UFP; PM<0.1]) and biomarkers were measured longitudinally at pre-specified intervals and course PM fraction (PM10-2.5) was calculated. Biomarkers were categorized based on associations with biologic mechanisms: inflammation (white blood cell count, interleukin [IL]-6, IL-8, IL-1β, tumor necrosis factor-α, interferon-γ, serum amyloid A), platelet activation (P-selectin, CD40 ligand [CD40L], 11-dehdydro-thromboxane-B2 [11dTxB2]), endothelial dysfunction (Vascular Cell Adhesion Molecule [VCAM]-1, Intercellular Adhesion Molecule [ICAM]-1), and oxidative stress (thiobarbituric acid reactive substances [TBARS], 8-hydroxydeoxyguanosine, 8-isoprostane). Associations between PM concentrations and each biomarker were analyzed using multivariable linear mixed models. An intention-to-treat analysis was performed to evaluate the air cleaner intervention on the biomarker levels longitudinally. ResultsFifty-eight participants were randomized to each group. Finer PM was more strongly associated with higher IL-8 (mean difference per doubling: UFP 13.9% [p = 0.02], PM2.5 6.8% [p = 0.002], PM10-2.5 5.0% [p = 0.02]) while interferon-γ was associated with UFP and IL-1β with PM10-2.5. UFP and PM2.5 were associated with elevated levels of the oxidative stress biomarkers TBARS and 8-isoprostane respectively. For platelet activation markers, UFP was associated with higher 11dTxB2 while PM2.5 was associated with higher P-selectin and CD40L. Pollutants were not associated with biomarkers of endothelial dysfunction. In intention-to-treat analysis there was no association of the air cleaner intervention with any of the biomarkers. DiscussionAmong former smokers with COPD, elevated levels of indoor air pollutants, particularly ultrafine particles (PM<0.1), were associated with elevated biomarkers of inflammation, platelet activation, and oxidative stress. However, an air cleaner intervention that reduced PM did not significantly reduce biomarker levels.

Estimation of Radon/Thoron and their progeny concentration in some dwellings and exhalation rates from soils of Samana city, Patiala

The study of indoor pollutants and radioactive nuclides imposes importance on human health as we spend most of our time indoors. Out of all the natural radioactive elements, Radon-222 and Radon220 are present in large abundance indoors. Both are radioactive and decay to various short-lived progenies by emitting high-energy alpha particles, so inhalation of such gases can harm the human body in various ways. In the present report, the concentration of Rn-222 and Rn-220 and its progenies are estimated from some dwellings of Samana city of Patiala district, Punjab. Pin-hole dosimeters with DRPS and DTPS were employed in 15 houses in the study area to measure indoor Rn-222 and Rn-220 concentrations. The concentration of Rn-222 ranges between 401.96 Bq/m3 and 27.36 Bq/m3 with mean value of 138.82 Bq/m3, and the concentration of Rn-220 varies from 222.2 Bq/ m3 to 50 Bq/m3 with the mean weight of 131.12 Bq/m3. The average inhalation dose was also calculated from the results and was found to have an average value of 2.19 mSv per year. The average weight of radon concentration was below the ICRP recommendation of 200-300 Bq/m3 but the value is above these limits at some locations. Radon and thoron emission rates from soil samples near to the dwellings was also calculated.

General Public Knowledge, Attitude, and Practice Regarding the Impact of Air Pollution and Cardiopulmonary Diseases in Jeddah, Saudi Arabia.

Introduction Air pollution is a critical public health issue associated with various respiratory and cardiovascular diseases. The lungs and heart are the organs most affected by air pollution, and damage to these organs is strongly associated with inhaled particulate matter produced by burning fossil fuels. Household and ambient air pollution have been closely linked to lower respiratory infections, with ambient air pollution alone estimated to be responsible for millions of deaths globally each year.Therefore, this study aimed to assess the general public knowledge attitude and practice regarding air pollution and cardiopulmonary morbidity in Jeddah, Saudi Arabia. Methods The study was conducted in Saudi Arabia using a self-administered questionnaire distributed through popular social media apps. A snowball sampling technique was used, including only Saudi citizens aged 18 or older. The questionnaire consisted of 30 questions derived from a comprehensive literature review on the subject matter. Questions were validated through face validity, pilot testing, and Cronbach's alpha reliability measurement. The questionnaire included questions on demographic data, knowledge of air pollution, the relationship between air pollution and cardiopulmonary diseases, and attitudes and practices toward lowering exposure to air pollution. Results The study included 649 participants, with a mean age of 32.11 ± 13.47 years, and over half were females (54.7%). Most participants were aware of outdoor and indoor air pollution, but only a tiny percentage recognized cooking as a primary indoor source of pollution. However, the majority believed that indoor pollution could contribute to outdoor pollution. Participants associated air pollution with cardiopulmonary diseases, mainly secondhand tobacco smoke and outdoor air pollution caused by factories and industrial facilities. Knowledge and practice levels varied, with older individuals, females, and those in non-health-related occupations having higher levels of knowledge. Positive attitudes, particularly believing that moving to a less polluted area improves health, were associated with better knowledge. Females exhibited better air pollution-related practices, and there was a positive correlation between knowledge and practice scores. Conclusion The study highlighted the need for targeted public health campaigns to improve awareness and promote healthier practices, particularly among young adults, to mitigate the potential health impacts of air pollution, especially cardiopulmonary health.

Effects of Indoor Plants on Organic Chemicals Released from Furniture and Decoration Element

Plants have been used for centuries to decorate homes and add a touch of nature to interiors. Beyond their aesthetic appeal, plants have numerous benefits for indoor environments. Research has shown that plants can purify the air, improve indoor air quality and have psychological and physiological benefits. In this research, it aims to figure out the extent of knowing the effects of indoor plants on organic chemicals emitted from furniture and decoration elements. For this purpose, 225 randomly selected people participated in the prepared research questionnaire. According to the results of the survey, it was determined that the 18-25 age group participants and the participants with postgraduate education had a higher level of knowledge about the effects of plants on indoor pollutants compared to the participants in the other age and education groups. On the other hand, no significant difference was found between the evaluations of male and female participants regarding the effects of plants on indoor pollutants. When these results are examined in general, it is seen that the participants do not have enough information about the effects of indoor plants on the organic chemicals emitted from the furniture and decoration elements. As a result, it has been revealed that users should be informed about the effects of indoor plants on organic chemicals and awareness should be raised on this issue. And it has been reported that increasing the level of knowledge on this subject can provide significant contributions to human health.

Study on revision of standard limits for benzene in"Standards for indoor air quality（GB/T 18883-2022）"in China

Benzene, as a major indoor pollutant, has received widespread attention. In order to better control indoor benzene pollution and protect people's health, the limit value of benzene in the"Standards for indoor air quality (GB/T 18883-2022)'' was reduced from 0.11 mg/m3 to 0.03 mg/m3. This study reviewed and discussed the relevant technical contents of the determination of benzene limit value, including the exposure status of benzene, health effects, and derivation of the limit value. It also proposed prospects for the future direction of formulating indoor air benzene standards.

ZnO quantum dots sensitized ZnSnO3 for highly formaldehyde sensing at a low temperature

Developing gas sensors for formaldehyde vapor detection is necessary. Metal oxide semiconductor (MOS) exhibited good formaldehyde sensing properties but with high working temperature and unsatisfactory selectivity. Herein, ZnSnO3 was sensitized by ZnO QDs modification for high-performance formaldehyde sensing at low working temperatures via simple immersion method. Meanwhile, SnO2 QDs instead of ZnO QDs was also modified on ZnSnO3 nanocubes. The result indicated both ZnO QDs and SnO2 QDs modification greatly improved gas sensing response and lower the working temperature of ZnSnO3 to formaldehyde. Whereas, the obtained ZnSnO3/ZnO QDs composite (ZSO/ZQD) containing 5 wt% ZnO QDs (ZSO/ZQD-0.05) showed a highest response value of 613.3–100 ppm formaldehyde at 70℃ with good reversibility and stability, which was nearly 20 times of bare ZnSnO3 and 6 times of SnO2 QDs modified ZnSnO3. The detection limit reached 100 ppb formaldehyde. The formaldehyde sensing performance of ZSO/ZQD-0.05 composite was checked in presence of simulated indoor pollutants. Its improved sensor performance was mainly attributed to ZnO QDs, which played roles in forming rich heterojunctions with ZnSnO3, increasing the surface area, and providing oxygen deficiency for formaldehyde sensing reaction. This provided an alternative way to improving the sensing properties of MOS by QDs modification.

Indoor thermal comfort comparison between passive solar house with active solar heating and without active solar heating in Tibetan

Passive solar house technology has been spread for many farmers and herdsmen to improve the indoor thermal environment in Tibetan. However, due to lackage of fuels and arid cold in winter, dry cow dung and coal are popularly fired in stove in passive solar houses, which leads to indoor air pollution and poor indoor comfort. For improving indoor thermal comfort of Tibetan, an active solar heating system which consists of 7 sets of tandem solar water heaters with 30 glass evacuated solar tubes, low temperature floor heating and circulation controller was developed and tested for a common house without insulation in Gan-nan Tibetan area. Its indoor environment was compared and evaluated by PMV-PPD and LPD method to that of the same passive solar house heated by coal stove. On sunny, cloudy and snow days, the active solar heating system provided 113.1, 46.4 and 26.3 kWh of heat to room. The indoor humidity and wind speed of the experimental building were better. The indoor temperatures were 17.2-20.7, 14.9-20.5 and 11.0-14.8°C, while the compared building were 8.9-14.8, 10.1-12.1 and 7.2-10.5°C. The maximum temperature difference between head and ankle were 1.7, 1.6 and 0.9℃, and the compared building were 4, 4 and 4.7℃. The PMV-PPD on sunny day were class I and II; on cloudy day were class I, II and III; on snow day was class III. On sunny and cloudy days, the LPD were class I, on snow day was class I, II and III. The PMV-PPD and LPD for typical days of the compared building were class III. During the 179 days, the mean indoor temperature exceeded 14 ℃ for 81 days, the solar active heating system provided 12471 kWh of heat to room. The CO2 emission reduction was 12905 kg. The system's dynamic payback period were 2.57 years.

Protective role of Ibuprofen-Curcumin co-load nanomicelles against oxidative stress and inflammasome activation mediated by indoor pollution exposure in A549 cells

Protective role of Ibuprofen-Curcumin co-load nanomicelles against oxidative stress and inflammasome activation mediated by indoor pollution exposure in A549 cells

Impact of NO2 emissions from household heating systems with wall-mounted gas stoves on indoor and ambient air quality in Chinese urban areas

Nitrogen dioxide (NO2) has been discussed as a typical indoor pollutant for decades. As an increasingly popular heating method, household heating system (HHS) with wall-mounted natural gas stoves has led to a continuous increase in the emission of NO2. The absence of legal regulations and strict limits for NO2 emissions from wall-mounted gas stoves has led to a significant exceedance of indoor NO2 concentrations beyond the permissible value. However, this issue is rarely taken into consideration. In this study, we present the first report on NO2 emissions from wall-mounted gas stoves for household heating and their impact on indoor and ambient air quality in Chinese urban areas based on in-situ measurements and numerical simulations. On heating days, the observed indoor NO2 concentration is within 80-200 μg/m3, much higher than the outdoor atmospheric concentration. With a low emission grade of the wall-mounted gas stoves, it is estimated that >10 % of residents in a typical residential building area are exposed to a high NO2 concentration of >200 μg/m3, and >50 % of residents are exposed to a concentration of >80 μg/m3. In addition, the indoor NO2 concentration shows an obvious non-uniform distribution with the floor in residential buildings. The NO2 emission from residential natural gas heating also shows an obvious impact on the microenvironment around buildings, which is primarily determined by the emission grade of the stoves. The findings highlight that HHS has become a non-negligible source of indoor NO2 pollution in China. It is urgently necessary to formulate NO2 emission limit standards for wall-mounted gas stoves in Chinese urban areas and upgrade traditional natural gas heaters with efficient emission reduction technologies.