Indoor air pollution: a global health concern

Exposure to volatile organic compounds in offices and in residential and educational buildings in the European Union between 2010 and 2023: A systematic review and health risk assessment

Chronic exposure to indoor volatile organic compounds (VOCs) can result in several adverse effects including cancers. We review reports of levels of VOCs in offices and in residential and educational buildings in the member states of the European Union (EU) published between 2010 and 2023. We use these data to assess the risk to population health by estimating lifetime exposure to indoor VOCs and resulting non-cancer and cancer risks and, from that, the burden of cancer attributable to VOC exposure and associated economic losses. Our systematic review identified 1783 articles, of which 184 were examined in detail, with 58 yielding relevant data. After combining data on VOC concentrations separately for EU countries and building types, non-cancer and cancer risks were assessed in terms of hazard quotient and lifetime excess cancer risk (LECR) using probabilistic Monte Carlo Simulations. The LECR was used to estimate disability adjusted life years (DALYs) from VOC-related cancers and associated costs. We find that the LECR associated with formaldehyde exposure was above the acceptable risk level (ARL) in France and Germany and that of from exposure to benzene was also above the ARL in Spanish females. The sum of DALYs and related costs/1,000,000 population/year from exposure to acetaldehyde, benzene, formaldehyde, tetrachloroethylene, and trichloroethylene were 4.02 and €41,010, respectively, in France, those from exposure to acetaldehyde, benzene, carbon tetrachloride, formaldehyde, and trichloroethylene were 3.91 and €39,590 in Germany, and those from exposure to benzene were 0.1 and €1030 in Spain. Taken as a whole, these findings show that indoor exposure to VOCs remains a public health concern in the EU. Although the EU has set limits for certain VOCs, further measures are needed to restrict the use of these chemicals in consumer products.

Atomically thin-layered WS2based resistive sensors for detection of CO and NO2at room temperature

The number of layers present in a two-dimensional (2D) nanomaterial plays a critical role in applications that involve surface interaction, for example, gas sensing. This paper reports the synthesis of 2D WS2nanoflakes using the facile liquid exfoliation technique. The nanoflakes were exfoliated using bath sonication (BS-WS2) and probe sonication (PS-WS2). The thickness of the BS-WS2was found to range between 70 and 200 nm, and that of PS-WS2varied from 0.6 to 80 nm, indicating the presence of single to few layers of WS2when characterized using atomic force microscope. All the WS2samples were thoroughly characterized using electron microscopes, x-ray diffractometer, Raman spectroscopy, UV-Visible spectroscopy, Fourier transform infrared spectroscope, and thermogravimetric analyser. Both the nanostructured samples were exposed to 2 ppm of NO2at room temperature. Interestingly, BS-WS2which comprises of a greater number of WS2layers exhibited -14.2% response as against -3.4% response of PS-WS2, the atomically thin sample. The BS-WS2sample was found to be highly selective towards NO2but was slower (with incomplete recovery) as compared to PS-WS2. The PS-WS2sample was observed to exhibit -11.9% to -27.4% response to 2-10 ppm of CO and -3.4%-35.2% response to 2-10 ppm of NO2at room temperature, thereby exhibiting the potential to detect two gases simultaneously. These gases could be accurately predicted and quantified if the response times of the PS-WS2sample were considered. The atomically thin WS2-based sensor exhibited a limit of detection of 131 and 81 ppb for CO and NO2, respectively.

Low-Cost Hourly Ambient Black Carbon Measurements at Multiple Cities in Africa

There is a notable lack of continuous monitoring of air pollutants in the Global South, especially for measuring chemical composition, due to the high cost of regulatory monitors. Using our previously developed low-cost method to quantify black carbon (BC) in fine particulate matter (PM2.5) by analyzing reflected red light from ambient particle deposits on glass fiber filters, we estimated hourly ambient BC concentrations with filter tapes from beta attenuation monitors (BAMs). BC measurements obtained through this method were validated against a reference aethalometer between August 2 and 23, 2023 in Addis Ababa, Ethiopia, demonstrating a very strong agreement (R2 = 0.95 and slope = 0.97). We present hourly BC for three cities in sub-Saharan Africa (SSA) and one in North America: Abidjan (Côte d'Ivoire), Accra (Ghana), Addis Ababa (Ethiopia), and Pittsburgh (USA). The average BC concentrations for the measurement period at the Abidjan, Accra, Addis Ababa Central summer, Addis Ababa Central winter, Addis Ababa Jacros winter, and Pittsburgh sites were 3.85 μg/m3, 5.33 μg/m3, 5.63 μg/m3, 3.89 μg/m3, 9.14 μg/m3, and 0.52 μg/m3, respectively. BC made up 14-20% of PM2.5 mass in the SSA cities compared to only 5.6% in Pittsburgh. The hourly BC data at all sites (SSA and North America) show a pronounced diurnal pattern with prominent peaks during the morning and evening rush hours on workdays. A comparison between our measurements and the Goddard Earth Observing System Composition Forecast (GEOS-CF) estimates shows that the model performs well in predicting PM2.5 for most sites but struggles to predict BC at an hourly resolution. Adding more ground measurements could help evaluate and improve the performance of chemical transport models. Our method can potentially use existing BAM networks, such as BAMs at U.S. Embassies around the globe, to measure hourly BC concentrations. The PM2.5 composition data, thus acquired, can be crucial in identifying emission sources and help in effective policymaking in SSA.

Effects of air pollution on global health: evidence from the global burden of disease study in the BRICS countries

PURPOSE

Considering the dynamic influence of environmental, social, economic, and political factors in the emergence and growth of the BRICS countries (Brazil, Russia, India, China, and South Africa) over the years and pre-existing differences, the adverse effects of air pollution on the health and well-being of the people have remained major areas of academic inquiry and policy interventions. The present study examines the global trend of deaths and Disability Adjusted Life Years (DALYs) attributable to air pollution with particular reference to the BRICS countries for the period 1990 to 2019.

METHODS

This study has used the global burden of disease estimates by using different rounds of the Global Burden of Disease (GBD) study report published by the Institute of Health Metrics Evaluation. This study has calculated the cause of death and DALYs due to environmental risk factors (i.e. Air pollution). Data analysis has been done by using the standard formula for the calculation of death (mortality) rate and DALYs rate. Similarly, we calculated the age and gender-wise death and DALYs rate by using the appropriate numerator and denominator.

RESULTS

The study discovered a significant shift in disease patterns over this period, as communicable diseases like respiratory infections and tuberculosis were replaced by non-communicable diseases such as ischemic heart disease (17.2 million), chronic obstructive pulmonary disease (14.59 million), and stroke (17.02 million) as the primary causes of air pollution-related deaths in 2019 at the global level. Additionally, the study identified a worrying increase in deaths linked to neonatal disorders and respiratory infections caused by ambient particulate matter pollution in South Africa, India, and Brazil. The impact of air pollution on public health is evident across different age groups and genders, with people aged 50-69 years, those aged 70 and above, and children under 5 years being more vulnerable. Furthermore, the male population is disproportionately affected by communicable and noncommunicable diseases caused by air pollution.

CONCLUSION

The study highlights the need for policymakers to implement evidence-based interventions to tackle this global health problem. The interventions should aim to reduce the emerging crisis of non-communicable diseases related to air pollution, particularly among vulnerable age groups and the male population, ultimately improving public health outcomes.

Association between exposure to smoke from cooking fuels and anaemia among women of reproductive age in Ghana

In low- and middle-income countries, indoor air pollution (IAP) is a serious public health concern, especially for women and children who cook with solid fuels. IAP exposure has been linked to a number of medical conditions, including pneumonia, ischemic heart disease, stroke, chronic obstructive pulmonary disease (COPD), lung cancer, and anaemia. Around 500 million women of reproductive age (WRA) suffer from anaemia globally, with an estimated 190 million cases in sub-Saharan Africa (SSA). This study, which is based on prior research, investigates the relationship between IAP exposure and anaemia among WRA in Ghana. A diverse sample of 2,406 WRA living in Ghana were interviewed, of which 58.06% were anaemic and used high-pollutant fuels for cooking. Age, place of residence, region, education level, religion, ethnicity, wealth index, type of drinking water, type of toilet facility, and type of cooking fuels were all found to be significantly linked with anaemic state by bivariate analysis. Type of cooking fuels utilized, age, region of residence, and the type of residence were shown to be significant predictors of anaemia status using sequential binary logit regression models. The results emphasise the critical need for efforts to promote the usage of clean cooking fuel in an attempt to lower anaemia prevalence in Ghana. To reduce dependency on solid fuels for cooking, initiatives should promote the use of cleaner cooking fuels and enhance the socioeconomic status of households. These interventions could have significant public health effects by reducing the burden of anaemia and improving maternal and child health outcomes due to the prevalence of anaemia among WRA. Overall, this study sheds light on the relationship between IAP exposure and anaemia in Ghana and highlights the demand for focused public health initiatives to address this serious health problem.

Household indoor air quality in northeast China: On-site inspection and measurement in 399 Tianjin area residences

There has been an increased concern on indoor air quality (IAQ) in residences since the majority of individuals' time is mainly spent indoors. We inspected and measured indoor environmental parameters in 399 homes in northeast China in order to study IAQ. We systematically measured multilevel environmental parameters (physical, chemical, and biological) in children's bedrooms during all seasons. The results indicated that the median values for indoor temperature, relative humidity, total volatile organic compounds (TVOC), and formaldehyde concentrations throughout the year were within the Chinese national standards. However, the median carbon dioxide concentrations exceeded 1000 ppm during spring, autumn, and winter. In the same seasons, the air change rate (ACR) was below the minimum required level of 0.5 h-1. Di-2-ethylhexyl phthalate (DEHP), di-n-butyl phthalate (DnBP), and di-isobutyl phthalate (DiBP) were predominantly detected in settled dust, displaying median concentrations of 126.9, 41.5, and 16.3 μg/g, respectively. Notably, phthalate concentrations were significantly higher in urban houses as compared to rural houses. Furthermore, median concentrations of Dermatophagoides farinae (Der f) and endotoxin were 689.4 ng/g and 3689.1 EU/g, respectively, trending higher in winter than summer. There was a negative correlation between ACR and chemical pollutants (TVOC, formaldehyde, and DiBP). In conclusion, northeast Chinese homes had poor indoor air quality with ubiquitous exposure to modern chemical compounds and insufficient ventilation.

Association between air pollution and skin cutaneous melanoma: A Mendelian randomization study

There has been a consistent and notable increase in the global prevalence of skin cutaneous melanoma (SKCM). Although genetic factors are closely associated with the occurrence and development of melanoma, the potential influence of environmental factors cannot be overlooked. The existing literature lacks a definitive consensus on the correlation between air pollution and the incidence rate of SKCM. This study seeks to investigate the causal relationship between air pollution, specifically focusing on particulate matter (PM) 2.5, PM2.5-10, PM10, and nitrogen oxides, and the risk of SKCM. A 2-sample Mendelian randomization (MR) method was applied, utilizing extensive publicly accessible genome-wide association studies summary datasets within European populations. The primary analytical method employed was the inverse variance weighted method. Supplementary methods, including the weighted median model, MR-Egger, simple model, and weighted model, were chosen to ensure robust analysis. Heterogeneity assessment was conducted using Cochran's Q test. To identify potential pleiotropy, both MR-Egger regression and the MR-PRESSO global test were employed. Additionally, a sensitivity analysis was performed using the leave-one-out method. The analysis revealed no statistically significant association between air pollution and SKCM risk, with specific findings as follows: PM2.5 (P = .485), PM2.5-10 (P = .535), PM10 (P = .136), and nitrogen oxides (P = .745). While some results exhibited heterogeneity, all findings demonstrated an absence of pleiotropy. This study did not find substantive evidence supporting a causal relationship between air pollution and the risk of SKCM within European populations. The comprehensive MR analysis, encompassing various pollutants, suggests that environmental factors such as air pollution may not be significant contributors to the development of SKCM.

Gas-Phase and Surface-Initiated Reactions of Household Bleach and Terpene-Containing Cleaning Products Yield Chlorination and Oxidation Products Adsorbed onto Indoor Relevant Surfaces

The use of household bleach cleaning products results in emissions of highly oxidative gaseous species, such as hypochlorous acid (HOCl) and chlorine (Cl2). These species readily react with volatile organic compounds (VOCs), such as limonene, one of the most abundant compounds found in indoor enviroments. In this study, reactions of HOCl/Cl2 with limonene in the gas phase and on indoor relevant surfaces were investigated. Using an environmental Teflon chamber, we show that silica (SiO2), a proxy for window glass, and rutile (TiO2), a component of paint and self-cleaning surfaces, act as a reservoir for adsorption of gas-phase products formed between HOCl/Cl2 and limonene. Furthermore, high-resolution mass spectrometry (HRMS) shows that the gas-phase reaction products of HOCl/Cl2 and limonene readily adsorb on both SiO2 and TiO2. Surface-mediated reactions can also occur, leading to the formation of new chlorine- and oxygen-containing products. Transmission Fourier-transform infrared (FTIR) spectroscopy of adsorption and desorption of bleach and terpene oxidation products indicates that these chlorine- and oxygen-containing products strongly adsorb on both SiO2 and TiO2 surfaces for days, providing potential sources of human exposure and sinks for additional heterogeneous reactions.

Measuring semi-volatile organic compound exposures during pregnancy using silicone wristbands

Silicone wristbands were utilized as personal passive samplers in a sub-cohort of 92 women, who participated in New York University Children's Health and Environment Study, to assess exposure to semi-volatile organic compounds (SVOCs). Wristbands were analyzed for 77 SVOCs, including halogenated and non-halogenated organophosphate esters (OPEs), polychlorinated biphenyls (PCBs), pesticides, phthalates, and brominated flame retardants (BFRs) (e.g. polybrominated diphenyl ethers (PBDEs)). This study aimed to look for patterns in chemical exposure utilizing participant demographics gathered from a questionnaire, and chemical exposure data across multiple timepoints during pregnancy. Analysis focused on 27 compounds detected in at least 80% of the wristbands examined. The chemicals detected most frequently included two pesticides, eight phthalates, one phthalate alternative, seven BFRs, and nine OPEs, including isopropylated and tert-butylated triarylphosphate esters (ITPs and TBPPs). Co-exposure to different SVOCs was most prominent in compounds that were within the same chemical class or were used in similar consumer applications such as phthalates and OPEs, which are often used as plasticizers. Pre-pregnancy BMI was positively associated with multiple compounds, and there were both positive and negative associations between women's parity and SVOC exposure. Outdoor temperature was not correlated with the wristband concentrations over a five-day sampling period. Lastly, significant and moderately high Intraclass Correlation Coefficient (ICC) (0.66-0.84) values for phthalate measurementsacross pregnancy indicate chronic exposure and suggest that using wristbands during one sampling period may reliably predict exposure. However, multiple sampling periods may be necessary to accurately determine indoor exposure to other SVOCs including OPEs and BFRs.

A comparative study of life-years lost attributable to air particulate matter in Asia-Pacific and European countries

Air particulate matter (PM) and its harmful effects on human health are of great concern globally due to all-cause and cause-specific mortality impacts across different population groups. While Europe has made significant progress in reducing particulate air pollution-related mortality through innovative technologies and policies, many countries in Asia-Pacific region still rely on high-polluting technologies and have yet to implement effective policies to address this issue, resulting in higher levels of mortality due to air pollution in the region. This study has three aims related to quantifying life-years lost (LYL) attributable to PM, and further separated into ambient PM and household air pollution (HAP): (1) to investigate LYL by causes of death; (2) to compare LYL between Asia-Pacific (APAC) and Europe; and (3) to assess LYL across different socio-demographic index (SDI) countries. The data used come from the Institute for Health Metrics and Evaluation (IHME) and Health Effects Institute (HEI). Our results show that average LYL due to PM in APAC was greater than in Europe, with some Pacific island countries particularly affected by the exposure to HAP. Three quarters of LYL came from premature deaths by ischemic heart disease and stroke, in both continents. There were significant differences between SDI groups for causes of death due to ambient PM and HAP. Our findings call for urgent improvement of clean air to reduce indoor and outdoor air pollution-related mortality in the APAC region.

Indoor air pollutants and respiratory symptoms among residents of an informal urban settlement in Uganda: A cross-sectional study

BACKGROUND

Indoor air pollutants (IAP) and household conditions such as dampness, crowding and chemical exposures have been associated with acute and chronic respiratory infections. In Uganda, literature on the effects of IAP on respiratory outcomes in informal settlements is limited.

METHODS

We describe the baseline household characteristics of 284 adults and their children in an informal settlement in Uganda from April to May 2022. We monitored same-day indoor concentrations of particulate matter PM2.5, PM10, Carbon monoxide (CO), relative humidity %, and temperature from 9 am to 2 pm and interviewed caregivers/mothers about their respiratory symptoms and those of their children in the previous 30 days. We employed robust Poisson regressions to evaluate the associations between indoor air indicators and respiratory health symptoms.

RESULTS

Approximately 94.7% of households primarily used biomass fuels and 32.7% cooked from inside their dwelling rooms. The median PM2.5, PM10 and CO levels were 49.5 (Interquartile range (IQR) = 31.1,86.2) μg/m3, 73.6 (IQR = 47.3,130.5) μg/m3 and 7.70 (IQR = 4.1,12.5) ppm respectively. Among adults, a 10 unit increase in PM2.5 was associated with cough (Prevalence Ratio (PR) = 3.75, 95%CI 1.15-1.55). Dwelling unit dampness was associated with phlegm (PR = 2.53, 95%CI = 1.39-4.61) and shortness of breath (PR = 1.78, 95% CI 1.23-2.54) while cooking from outside the house was protective against shortness of breath (PR = 0.62, 95% CI = 0.44-0.87). In children, dampness was associated with phlegm (PR = 13.87, 95% CI 3.16-60.91) and cough (PR = 1.62, 95% CI 1.12-2.34) while indoor residual spraying was associated with phlegm (PR = 3.36, 95%CI 1.71-6.61).

CONCLUSION

Poor indoor air conditions were associated with respiratory symptoms in adults and children. Efforts to address indoor air pollution should be made to protect adults and children from adverse health effects.

Method Development for Detecting Low Level Volatile Organic Compounds (VOCs) among Workers and Residents from a Carpentry Work Shop in a Palestinian Village

Volatile organic compounds (VOCs) are considered a major public health concern in industrial location areas. The presence of exposure to (VOCs) has raised concern regarding the health effects caused by chronic human exposure as this will increase cancer diseases in the village. An analytical method has been developed and modified to help us detect 38 VOCs in the blood of 38 volunteers who are related to a carpentry shop at the parts-per-trillion level. To measure and evaluate the potential risk, several devices, such as portable passive monitors and air-collected samples, in addition to blood concentration, were used to study three different occupational groups. Ten of the volunteers are employees at the shop, 10 volunteers live very close to the shop, and 10 of them are students in an elementary school very close to the shop. In this study, we developed an automated analytical method using headspace (HS) together with solid-phase microextraction (SPME) connected to capillary gas chromatography (GC) equipped with quadrupole mass spectrometry (MS). The detection limits for the method used were measured in the range from 0.001 to 0.15 ng/L, using linear calibration curves that have three orders of magnitude. The detected concentrations ranged from 3 ng L^-1 for trichloroethene to 91 ng L^-1 for toluene and 270 ng L^-1 for 2,4-diisocyanate, which was derived from the paint solvents used for the wood in the carpentry shop and the paints on the walls. More than half of all assessed species (80%) had mean concentration values less than 50 ng L^-1, which is the maximum allowed for most VOCs. The major chemical types among the compounds quantified will be those we found in our previous study in the surrounding air of a carpentry workshop in Deir Ballout in Palestine, which were toluene diisocyanate and butyl cyanate. Some were found to be highly present air. Most of the measurements were below the guidelines of the World Health Organization (WHO). Despite the fact that this study only involved a small number of smokers, smoking was found to be connected with several blood and breath components. This group includes unsaturated hydrocarbons (1,3-butadiene, 1,3-pentadiene, 2-butene), furans (2,5-dimethylfuran), and acetonitrile. The proposed classification of measured species into systemic (blood-borne) and exogenous volatiles is strictly hypothetical, as some species may have several origins.

Status and frontier analysis of indoor PM2.5-related health effects: a bibliometric analysis

Epidemiological data indicate atmospheric particulate matter, especially fine particulate matter (PM_2.5), has many negative effects on human health. Of note, people spend about 90% of their time indoors. More importantly, according to the World Health Organization (WHO) statistics, indoor air pollution causes nearly 1.6 million deaths each year, and it is considered as one of the major health risk factors. In order to obtain a deeper understanding of the harmful effects of indoor PM_2.5 on human health, we used bibliometric software to summarize articles in this field. In conclusion, since 2000, the annual publication volume has increased year by year. America topped the list for the number of articles, and Professor Petros Koutrakis and Harvard University were the author and institution with the most published in this research area, respectively. Over the past decade, scholars gradually paid attention to molecular mechanisms, therefore, the toxicity can be better explored. Particularly, apart from timely intervention and treatment for adverse consequences, it is necessary to effectively reduce indoor PM_2.5 through technologies. In addition, the trend and keywords analysis are favorable ways to find out future research hotspots. Hopefully, various countries and regions strengthen academic cooperation and integration of multi-disciplinary.

Can individual protective measures safeguard cardiopulmonary health from air pollution? A systematic review and meta-analysis

Evidence supporting the effect of individual protective measures (IPMs) on air pollution is relatively scarce. In this study, we performed a systematic review and meta-analysis to investigate the effects of air purifiers, air-purifying respirators, and cookstove changes on cardiopulmonary health outcomes. We searched PubMed, Scopus, and Web of Science until December 31, 2022, 90 articles and 39,760 participants were included. Two authors independently searched and selected the studies, extracted information, and assessed each study's quality and risk of bias. We performed meta-analyses when three or more studies were available for each IPMs, with comparable intervention and health outcome. Systematic review showed that IPMs were beneficial in children and elderly with asthma along with healthy individuals. Meta-analysis results showed a reduction in cardiopulmonary inflammation using air purifiers than in control groups (with sham/no filter) with a decrease in interleukin 6 by -0.247 μg/mL (95% confidence intervals [CI] = -0.413, -0.082). A sub-group analysis for air purifier as an IPMs in developing counties reduced fractional exhaled nitric oxide by -0.208 ppb (95% confidence intervals [CI] = -0.394, -0.022). However, evidence describing the effects of air purifying respirator and cook stove changes on cardiopulmonary outcomes remained insufficient. Therefore, air purifiers can serve as efficient IPMs against air pollution. The beneficial effect of air purifiers is likely to have a greater effect in developing countries than in developed countries.

CO2 in indoor environments: From environmental and health risk to potential renewable carbon source

In the developed world, individuals spend most of their time indoors. Poor Indoor Air Quality (IAQ) has a wide range of effects on human health. The burden of disease associated with indoor air accounts for millions of premature deaths related to exposure to Indoor Air Pollutants (IAPs). Among them, CO₂ is the most common one, and is commonly used as a metric of IAQ. Indoor CO₂ concentrations can be significantly higher than outdoors due to human metabolism and activities. Even in presence of ventilation, controlling the CO₂ concentration below the Indoor Air Guideline Values (IAGVs) is a challenge, and many indoor environments including schools, offices and transportation exceed the recommended value of 1000 ppm_v. This is often accompanied by high concentration of other pollutants, including bio-effluents such as viruses, and the importance of mitigating the transmission of airborne diseases has been highlighted by the COVID-19 pandemic. On the other hand, the relatively high CO₂ concentration of indoor environments presents a thermodynamic advantage for direct air capture (DAC) in comparison to atmospheric CO₂ concentration. This review aims to describe the issues associated with poor IAQ, and to demonstrate the potential of indoor CO₂ DAC to purify indoor air while generating a renewable carbon stream that can replace conventional carbon sources as a building block for chemical production, contributing to the circular economy.

In silico analysis of single nucleotide polymorphism (rs34377097) of TBXA2R gene and pollen induced bronchial asthma susceptibility in West Bengal population, India

Introduction

Prevalence of asthma is increasing steadily among general population in developing countries over past two decades. One of the causative agents of broncho-constriction in asthma is thromboxane A2 receptor (TBXA2R). However few studies of TBXA2R polymorphism were performed so far. The present study aimed to assess potential association of TBXA2R rs34377097 polymorphism causing missense substitution of Arginine to Leucine (R60L) among 482 patients diagnosed with pollen-induced asthma and 122 control participants from West Bengal, India. Also we performed in-silico analysis of mutated TBXA2R protein (R60L) using homology modeling.

Methods

Clinical parameters like Forced expiratory volume in 1 second (FEV₁), FEV₁/Forced vital capacity (FVC) and Peak expiratory flow rate (PEFR) were assessed using spirometry. Patients' sensitivity was measured by skin prick test (SPT) against 16 pollen allergens. Polymerase chain reaction-based Restriction fragment length polymorphism was done for genotyping. Structural model of wild type and homology model of polymorphic TBXA2R was generated using AlphaFold2 and MODELLER respectively. Electrostatic surface potential was calculated using APBS plugin in PyMol.

Results

Genotype frequencies differed significantly between the study groups (P=0.03). There was no significant deviation from Hardy-Weinberg equilibrium in control population (χ2=1.56). Asthmatic patients have significantly higher frequency of rs34377097TT genotype than control subjects (P=0.03). SPT of patients showed maximum sensitivity in A. indica (87.68%) followed by C. nusifera (83.29%) and C. pulcherima (74.94%). Significant difference existed for pollen sensitivity in adolescent and young adult (P=0.01) and between young and old adult (P=0.0003). Significant negative correlation was found between FEV1/FVC ratio and intensity of SPT reactions (P<0.0001). Significant association of FEV₁, FEV₁/FVC and PEFR was observed with pollen-induced asthma. Furthermore, risk allele T was found to be clinically correlated with lower FEV₁/FVC ratio (P=0.015) in patients. Our data showed R60L polymorphism, which was conserved across mammals, significantly reduced positive electrostatic charge of polymorphic protein in cytoplasmic domain thus altered downstream pathway and induced asthma response.

Discussion

The present in-silico study is the first one to report association of TBXA2R rs34377097 polymorphism in an Indian population. It may be used as prognostic marker of clinical response to asthma in West Bengal and possible target of therapeutics in future.

Effects of early life exposure to home environmental factors on childhood allergic rhinitis: Modifications by outdoor air pollution and temperature

BACKGROUND

There is growing evidence that allergic rhinitis (AR) is associated with indoor environmental factors, but their role in childhood AR during early life remains unclear.

OBJECTIVE

To investigate the association of preconceptional, prenatal, early postnatal, and current exposure to home environmental factors with childhood AR, and to further explore whether this association can be interacted by outdoor air pollution and temperature.

METHODS

A retrospective cohort study of 8689 preschool children was conducted during 2019-2020 in Changsha, China. A standard questionnaire was used to collect data on each family's health outcomes and home environments. We considered home environmental exposures during one year before conception, pregnancy, first year of life, and past year. Associations of indoor air pollution and allergens with AR were assessed by multiple logistic regression models.

RESULTS

Pre-birth exposure to indoor air pollution emitted by new furniture or redecoration and dampness related allergen derived from mold/damp stains and mold/damp clothes or bedding during 1 year before conception and pregnancy was significantly associated with increased AR, with adjusted ORs (95% CI) ranging from 1.35 (1.05-1.75) to 1.87 (1.55-2.27). Childhood AR was also significantly related with post-birth exposure to dampness related indoor allergen including mold/damp stains and mold/damp clothes or bedding in first year and past year and pollen allergen including total and nonflowing plants in past year, with a range of ORs (95% CI) from 1.20 (1.01-1.42) to 1.79 (1.42-2.27). We identified that pre-birth, particularly in utero exposure to both indoor air pollution from renovation and dampness related allergens, played a key role in AR development compared to post-birth exposures, and accumulative effect was observed with the highest risk of AR. High exposure to traffic-related air pollution (TRAP) including outdoor PM_2.5, NO₂, CO, and O₃, as well as living near traffic road not only significantly increased adverse effect of home environmental factors but also decreased protective effect of household dogs on childhood AR. Early life exposure to low temperature in pregnancy and high temperature in first year significantly increased AR risk of home environmental exposure. Sensitivity analysis indicated that some sub-groups were more susceptible to AR risk of home environmental exposure.

CONCLUSION

Our study suggests that pre-birth exposure to home environmental factors played an important role in AR development and this effect can be interacted by TRAP and temperature, which supports a hypothesis of "(pre)fetal origin of childhood AR".

Development and application of the Ames test using a direct-exposure module: The assessment of mutagenicity of incense and sidestream cigarette smoke

We had previously developed an improved Ames module to directly determine the mutagenicity of gaseous formaldehyde (HCHO) and toluene without liquid extraction. This study further evaluated the suitability and sensitivity of this module on whole and real polluted air samples. For this, two common brands of stick incense (A and B) and cigarettes (A and B) were harvested, and various types of incense smoke (IS) and sidestream cigarette smoke (SCS) samples were generated by lighting 3, 6, 12, 24, 30, or 36 incense sticks, and by lighting 1, 2, or 3 cigarettes, respectively, in an acrylic box. CO₂ , CO, total volatile organic compound (TVOC), PM_1.0, and HCHO concentrations in the air samples were determined, and all air samples did not partially fit the requirements of the air quality standards. The smoke samples were then directly exposed to TA100 for 10, 20, 30, or 60 min in our exposure module. Exposure to IS (brand A) for 30 to 60 min and exposure to IS (brand B) for 60 min led to statistically (p < 0.05) weak (below the twofold rule) but dose-dependent mutagenic activities either with or without metabolic activation. Furthermore, a short-term exposure (10-60 min) to SCS (brands A and B) displayed statistically significant (p < 0.05) direct-acting, indirect-acting, time- and dose-dependent mutagenic activities. Furthermore, our data also support that the liver S9 enzyme could enhance the mutagenic activities in most IS and SCS samples. This study confirmed that the modified Ames module can be applied to directly detect the mutagenic activities of real polluted air samples.

Polyurethane Foam Face Masks as a Dosimeter for Quantifying Personal Exposure to Airborne Volatile and Semi-Volatile Organic Compounds

Airborne volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) are commonly quantitated by collecting the analytes on solid sorbent tubes or passive air samplers, followed by solvent extraction and instrumental analysis, or by grab bag/canister measurements. We report herein a user-friendly sampling method by breathing through polyurethane foam (PUF) face masks to collect airborne VOCs and SVOCs for chemical analysis. Specifically, dibasic esters, phthalate esters, polycyclic aromatic hydrocarbons, linalool, and nicotine trapped on PUF masks were quantitated by gas chromatography-mass spectrometry analysis as model VOCs and SVOCs. Results showed that the amount of these model VOCs and SVOCs trapped on PUF masks is proportional to the exposure duration. After cross-validation by parallel sampling using XAD-2 packed sorbent tubes, the method was used to quantitate VOCs and SVOCs in a variety of indoor and outdoor environments with varying air concentrations of analytes, temperature, humidity, and wind speed. Because air pollution is considered a major cause of many human diseases and premature deaths and the developed PUF mask sampling method showed high trapping efficiencies for both VOCs and SVOCs, it is believed that the developed sampling method will find wide application in assessing air pollution-associated disease risks with possible extension to more classes of VOCs and SVOCs when coupled with suitable instrumental detection methods.

Investigation of indoor and outdoor air quality in a university campus during COVID-19 lock down period

The pandemic of COVID-19 currently shadows the world; the whole earth has been on an unprecedented lockdown. Social distancing among people interrupted domestic and international air traffic, suspended industrial productions and economic activities, and had various far-reaching and undetermined implications on air quality. Improvement in air quality has been reported in many cities during the lockdown. On March 22, 2020, the Turkish government enforced strict lockdown measures to reduce coronavirus disease transmission. This lockdown had a significant impact on the movement of people within the country, which resulted in a major drop in worldwide commercial activities. During this period, university campuses were emptied due to the transition to distance education. In this study, various air pollutants sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), fine particulate matter (PM_2.5), total bacteria, and total fungi were measured in different indoor environments at Eskişehir Technical University Campus in Eskişehir, Turkey during COVID-19 lock down period. Also, to calculate the indoor and outdoor ratios (I/O) of the pollutants, simultaneous outdoor measurements were also carried out. The average indoor SO_2, NO_2, O_3, and PM_2.5 concentrations in different indoor environments ranged between 2.10 and 54.58, 1.36-30.89, 12.01-39.05, and 21-94 μg/m³, respectively. The total number of bacteria and fungi ranged between 21.83-514.15 and 13.10-83.36 CFU/m³, respectively. Our study intends to give a glimpse to quantify the impact of a pandemic on air quality in different indoor environments in a university campus in Eskişehir, Turkey and calls for follow-up studies. Indoor concentrations were evaluated together with outdoor concentrations. In general, it can be said that the calculated I/O ratios for SO₂, NO₂, O₃, bacteria, and fungi were less than 1 in most indoor environments.

Association between visual emphysema and lung nodules on low-dose CT scan in a Chinese Lung Cancer Screening Program (Nelcin-B3)

OBJECTIVES

This study aimed to evaluate the association between visual emphysema and the presence of lung nodules, and Lung-RADS category with low-dose CT (LDCT).

METHODS

Baseline LDCT scans of 1162 participants from a lung cancer screening study (Nelcin-B3) performed in a Chinese general population were included. The presence, subtypes, and severity of emphysema (at least trace) were visually assessed by one radiologist. The presence, size, and classification of non-calcified lung nodules (≥ 30 mm³) and Lung-RADS category were independently assessed by another two radiologists. Multivariable logistic regression and stratified analyses were performed to estimate the association between emphysema and lung nodules, Lung-RADS category, after adjusting for age, sex, BMI, smoking status, pack-years, and passive smoking.

RESULTS

Emphysema and lung nodules were observed in 674 (58.0%) and 424 (36.5%) participants, respectively. Participants with emphysema had a 71% increased risk of having lung nodules (adjusted odds ratios, aOR: 1.71, 95% CI: 1.26-2.31) and 70% increased risk of positive Lung-RADS category (aOR: 1.70, 95% CI: 1.09-2.66) than those without emphysema. Participants with paraseptal emphysema (n = 47, 4.0%) were at a higher risk for lung nodules than those with centrilobular emphysema (CLE) (aOR: 2.43, 95% CI: 1.32-4.50 and aOR: 1.60, 95% CI: 1.23-2.09, respectively). Only CLE was associated with positive Lung-RADS category (p = 0.02). CLE severity was related to a higher risk of lung nodules (ranges aOR: 1.44-2.61, overall p < 0.01).

CONCLUSION

In a Chinese general population, visual emphysema based on LDCT is independently related to the presence of lung nodules (≥ 30 mm³) and specifically CLE subtype is related to positive Lung-RADS category. The risk of lung nodules increases with CLE severity.

KEY POINTS

• Participants with emphysema had an increased risk of having lung nodules, especially smokers. • Participants with PSE were at a higher risk for lung nodules than those with CLE, but nodules in participants with CLE had a higher risk of positive Lung-RADS category. • The risk of lung nodules increases with CLE severity.

Psychological Antecedents of the Intention to Open the Windows at Home and Exposure to a Ventilation Recommendation

Objective

The psychological antecedents of the intention to open the windows at home were explored through the Theory of Planned Behavior (TPB), supplemented with Habits regarding the behavior and contextual factors.

Design

A four-treatment design compared the effect of an exposure to a recommendation about home ventilation and the effect of one's own awareness odors (negative vs. positive) as a manipulated variable. Two quasi-experimental online surveys were conducted. A student sample (Study 1; N = 159) was replicated with a general population sample (Study 2; N = 338).

Results

Multiple hierarchical regression models were conducted (3 for Study 1; 3 for Study 2). The extended TPB model provided stable predictors explaining around sixty percent of variance. Attitude and Habits were the main predictors of window openings, Perceived Behavioral control as a secondary predictor. Perceived Behavioral Control contributed significatively with a negative interaction with Attitudes. Odor awareness decreased Intention to manually ventilate. No effect of recommendation was observed.

Discussion

The results filled a gap in the literature about the willingness to manually ventilate at home and efficacy of a recommendation. Practical implications argue that beyond a generic recommendation, effective messages need to be tailored regarding the determinants of willingness to open the windows.

Evaluation of indoor and outdoor air quality in university academic buildings and associated health risk

Air pollution is associated with several detrimental health conditions. This study assessed comfort parameters, priority air pollutants, hydrogen sulphide (H₂S), non-methane hydrocarbons (NMHCs), and volatile organic compounds (VOCs) in natural science departments in a university to understand their role in air pollutant concentrations in university environments and associated health risks. Levels of air pollutants in the departments varied. High CO₂ concentrations existed in all departments with highest levels of NMHC and VOC observed in the biochemistry, microbiology and biotechnology (BMBT) department. Highest Air quality index value of 111.3 was recorded for NO₂ in the BMBT department. Health risk associated with exposure to these pollutants was highest for occupants in the physiology, followed by the biodiversity, and finally BMBT department. Natural science departments seem to contribute significant amounts of H₂S, NO₂, NMHCs and TVOCs in university campuses. Additional ventilation and frequent monitoring of air quality in these departments are recommended.

Determination of the key parameters of VOCs emitted from multi-layer leather furniture using a region traversal approach

Volatile organic compounds (VOCs) emitted from indoor materials and products are one of the main factors affecting air quality and human health. Compared with building materials and wooden furniture, leather furniture has a more complex internal structure and uneven emission surfaces. The market share of leather furniture is relatively high, while investigation on this kind of furniture is relatively rare. In this study, we develop a region traversal method to measure the three key parameters of VOC emissions from typical two-layer leather furniture, i.e., the initial emittable concentration, the diffusion coefficient, and the partition coefficient. A series of experiments examining VOC emissions from a leather sofa under different conditions, were carried out in a 1 m³ chamber. This method locks the upper and lower limits of an optimal solution through loop calculation in parameter intervals, and demonstrates high accuracy, efficiency and robustness. The good agreement (R² > 0.95) between model predictions and experimental data confirms the reliability of this method. In addition, the influence of temperature and air exchange rate on the key parameters is explored. Results indicate that, increasing the temperature leads to an increase in D_m and a decrease in K, and that air exchange rate does not affect the key parameters, which is consistent with physical principles. The region traversal method is further applied to analyze the emission scenarios for other furniture, which is very helpful for indoor air quality pre-evaluation.

Investigation of Some Gaseous and Trace Metal Emissions With Their Emission Factors From Various Brands of Mosquito Coils Used in Nigeria

Mosquito coils of various brands are frequently burnt in indoor environments to drive away mosquitoes-the vector for malaria parasite in regions where the disease is endemic. Emissions from the coils could be a source of indoor air pollution. In this study, various brands of mosquito coils obtained from retail shops in Lagos, Nigeria were burnt in an environmental test box with a view to characterizing carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO₂) in the gaseous emissions as well as elemental concentrations of the ash. Emission characterization achieved with the RAS1700 bio-gas analyzer while AAS was adopted for elemental analysis of the mosquito coil ashes. The emission factor of CO, NO and NO₂ from the coil samples ranged between 0.00138 to 0.26277 μg/m³, 0.0002 to 0.00454 μg/m³, and 0.000074 to 0.00714 μg/m³, respectively. These values were found to be lower than permissible indoor levels recommended by NIOSH. The range of concentrations of Pb, Zn, Cd, Cr, Cu, As, Hg, Fe in the coil ashes from all the brands were 0.02 to 0.04 mg/g, 0.011 to 0.02 mg/g, 0.001 to 0.003 mg/g, 0.004 to 0.008 mg/g, 0.004 to 0.006 mg/g, 0.0001 to 0.0004 mg/g, 0.001 to 0.003 mg/g, and 0.124 to 0.14 mg/g, respectively. Although, the concentrations of the pollutants obtained in this study are within the recommended limits, prolong exposure could trigger chronic disease conditions. Adequate ventilation of indoor environments or utilization of mosquito nets in place of coils could be considered.

In-kitchen aerosol exposure in twelve cities across the globe

Poor ventilation and polluting cooking fuels in low-income homes cause high exposure, yet relevant global studies are limited. We assessed exposure to in-kitchen particulate matter (PM_2.5 and PM₁₀) employing similar instrumentation in 60 low-income homes across 12 cities: Dhaka (Bangladesh); Chennai (India); Nanjing (China); Medellín (Colombia); São Paulo (Brazil); Cairo (Egypt); Sulaymaniyah (Iraq); Addis Ababa (Ethiopia); Akure (Nigeria); Blantyre (Malawi); Dar-es-Salaam (Tanzania) and Nairobi (Kenya). Exposure profiles of kitchen occupants showed that fuel, kitchen volume, cooking type and ventilation were the most prominent factors affecting in-kitchen exposure. Different cuisines resulted in varying cooking durations and disproportional exposures. Occupants in Dhaka, Nanjing, Dar-es-Salaam and Nairobi spent > 40% of their cooking time frying (the highest particle emitting cooking activity) compared with ∼ 68% of time spent boiling/stewing in Cairo, Sulaymaniyah and Akure. The highest average PM_2.5 (PM₁₀) concentrations were in Dhaka 185 ± 48 (220 ± 58) μg m^-3 owing to small kitchen volume, extensive frying and prolonged cooking compared with the lowest in Medellín 10 ± 3 (14 ± 2) μg m^-3. Dual ventilation (mechanical and natural) in Chennai, Cairo and Sulaymaniyah reduced average in-kitchen PM_2.5 and PM₁₀ by 2.3- and 1.8-times compared with natural ventilation (open doors) in Addis Ababa, Dar-es-Salam and Nairobi. Using charcoal during cooking (Addis Ababa, Blantyre and Nairobi) increased PM_2.5 levels by 1.3- and 3.1-times compared with using natural gas (Nanjing, Medellin and Cairo) and LPG (Chennai, Sao Paulo and Sulaymaniyah), respectively. Smaller-volume kitchens (<15 m³; Dhaka and Nanjing) increased cooking exposure compared with their larger-volume counterparts (Medellin, Cairo and Sulaymaniyah). Potential exposure doses were highest for Asian, followed by African, Middle-eastern and South American homes. We recommend increased cooking exhaust extraction, cleaner fuels, awareness on improved cooking practices and minimising passive occupancy in kitchens to mitigate harmful cooking emissions.

Using Real Time Measurements to Derive the Indoor and Outdoor Contributions of Submicron Particulate Species and Trace Gases

The indoor environment is usually more polluted than outdoors due to emissions of gas and particle-phase pollutants from multiple sources, leading to their accumulation on top of the infiltration of outdoor pollution. While it is widely recognized that negative health effects arise from the exposure to outdoor air pollution, exposure to indoor pollutants also needs to be well assessed since we spend most of our time (~90%) breathing indoors. Indoor concentrations of pollutants are driven by physicochemical processes and chemical transformations taking place indoors, acting as sources and/or sinks. While these basic concepts are understood, assessing the contribution of each process is still challenging. In this study, we deployed online instrumentation in an unoccupied room to test a methodology for the apportionment of indoor and outdoor pollutant sources. This method was successfully applied to the apportionment of PM₁ and VOCs, however, there are limitations for reactive gases such as O₃. The results showed that this unoccupied indoor environment acts as a source of VOCs and contributes 87% on OVOCs and 6% on C_xH_y, while it acts as a sink for particles, likely due to losses through volatilization up to 60%.

The Adverse Effects of Air Pollution on the Eye: A Review

Air pollution is inevitably the result of human civilization, industrialization, and globalization. It is composed of a mixture of gases and particles at harmful levels. Particulate matter (PM), nitrogen oxides (NOx), and carbon dioxides (CO₂) are mainly generated from vehicle emissions and fuel consumption and are the main materials causing outdoor air pollution. Exposure to polluted outdoor air has been proven to be harmful to human eyes. On the other hand, indoor air pollution from environmental tobacco smoking, heating, cooking, or poor indoor ventilation is also related to several eye diseases, including conjunctivitis, glaucoma, cataracts, and age-related macular degeneration (AMD). In the past 30 years, no updated review has provided an overview of the impact of air pollution on the eye. We reviewed reports on air pollution and eye diseases in the last three decades in the PubMed database, Medline databases, and Google Scholar and discussed the effect of various outdoor and indoor pollutants on human eyes.

Rationally Designed TiO2 Nanostructures of Continuous Pore Network for Fast-Responding and Highly Sensitive Acetone Sensor

For the last several years, indoor air quality monitoring has been a significant issue due to the increasing time portion of indoor human activities. Especially, the early detection of volatile organic compounds potentially harmful to the human body by the prolonged exposure is the primary concern for public human health, and such technology is imperatively desired. In this study, highly porous and periodic 3D TiO₂ nanostructures are designed and studied for this concern. Specifically, extremely high gas molecule accessibility throughout the whole nanostructures and precisely controlled internecks of 3D TiO₂ nanostructures can achieve an unprecedented gas response of 299 to 50 ppm CH₃ COCH₃ with an extremely fast response time of less than 1s. The systematic approach to utilize the whole inner and outer surfaces of the gas sensing materials and periodically formed internecks to localize the current paths in this study can provide highly promising perspectives to advance the development of chemoresistive gas sensors using metal oxide nanostructures for the Internet of Everything application.

Removal of chemical hazardous compounds using CATACOAT, a nano-platinum thermal catalyst system

The performance of CATACOAT, a nano-platinum thermal catalyst system, was evaluated for the removal of chemical hazardous compounds from air. Xylene, benzene, styrene, and toluene were selected as standard volatile organic compounds (VOCs) in this study. In addition, formaldehyde was tested as a chemical hazardous compound. Each VOC, or formaldehyde, was evaporated in a 4,000 L chamber under controlled environments. At the maximum concentration point, CATACOAT was turned on and the concentrations of the chemical hazardous compounds were recorded for 5 h. The air purifier based on H-13-grade high-efficiency particulate air (HEPA) filter was tested in the same way to compare the effects of CATACOAT. Compared with the HEPA filter system, every VOC concentration was significantly decreased with the CATACOAT system only 0.025 h after turning on the air purifier (P values for xylene, benzene, styrene, and toluene are 0.00488, 0.01508, 0.00014, and 0.04690, respectively). After running the air cleaners for 5 h, every VOC and formaldehyde demonstrated significantly decreased concentrations with the CATACOAT system, compared with HEPA filter system (P values for xylene, benzene, styrene, toluene, and formaldehyde are 0.00034, 0.00009, 0.00008, 0.00001, and 0.00571, respectively). In conclusion, the CATACOAT may be a viable solution to control indoor air pollution.

Understanding "Atmosome", the Personal Atmospheric Exposome: Comprehensive Approach

BACKGROUND

Modern environmental health research extensively focuses on outdoor air pollutants and their effects on public health. However, research on monitoring and enhancing individual indoor air quality is lacking. The field of exposomics encompasses the totality of human environmental exposures and its effects on health. A subset of this exposome deals with atmospheric exposure, termed the "atmosome." The atmosome plays a pivotal role in health and has significant effects on DNA, metabolism, skin integrity, and lung health.

OBJECTIVE

The aim of this work is to develop a low-cost, comprehensive measurement system for collecting and analyzing atmosomic factors. The research explores the significance of the atmosome in personalized and preventive care for public health.

METHODS

An internet of things microcontroller-based system is introduced and demonstrated. The system collects real-time indoor air quality data and posts it to the cloud for immediate access.

RESULTS

The experimental results yield air quality measurements with an accuracy of 90% when compared with precalibrated commercial devices and demonstrate a direct correlation between lifestyle and air quality.

CONCLUSIONS

Quantifying the individual atmosome is a monumental step in advancing personalized health, medical research, and epidemiological research. The 2 main goals in this work are to present the atmosome as a measurable concept and to demonstrate how to implement it using low-cost electronics. By enabling atmosome measurements at a communal scale, this work also opens up potential new directions for public health research. Researchers will now have the data to model the impact of indoor air pollutants on the health of individuals, communities, and specific demographics, leading to novel approaches for predicting and preventing diseases.

Assessment of the mutagenicity of two common indoor air pollutants, formaldehyde and toluene

Traditionally, direct-reading instruments have been used to directly determine the concentrations of indoor air pollutants that may exceed the regulation limits. However, these instruments cannot directly assess the potential health hazards of these pollutants to humans. In this study, we developed and improved a bacterial reverse mutation assay (Ames test) by using a direct gas exposure module to directly determine the mutagenicity of indoor air quality using five tester bacterial strains (TA98, TA100, TA102, TA1535, and TA1537). Thereafter, the module was used to evaluate the effects of exposure time, different concentrations of HCHO or toluene, and mutagenic activities. We found that TA100 was the most sensitive strain and was reverted by relatively lower concentrations of 0.035 ppm HCHO. Furthermore, 50 ppm of toluene exposures caused a significant increase in the number of revertant colonies of TA100 without S9 activation at the 1.5-8-h exposure time intervals. Our findings provide new evidence that gaseous HCHO exposure could display weak but direct, time-dependent, and dose-dependent mutagenic activities. The weak, direct-acting, indirect-acting, and time-dependent mutagen of 50 ppm toluene was also confirmed. Moreover, our improved Ames module and the exposure conditions provided in this study can be further applied to evaluate the mutagenicity of indoor air quality.

Cytotoxicity analysis of biomass combustion particles in human pulmonary alveolar epithelial cells on an air-liquid interface/dynamic culture platform

BACKGROUND

Exposure to indoor air pollution from solid fuel combustion is associated with lung diseases and cancer. This study investigated the cytotoxicity and molecular mechanisms of biomass combustion-derived particles in human pulmonary alveolar epithelial cells (HPAEpiC) using a platform that combines air-liquid interface (ALI) and dynamic culture (DC) systems.

METHODS

HPAEpiC were cultured on the surface of polycarbonate (PC) membranes on the ALI-DC platform. The cells were sprayed with an aerosolized solution of biomass combustion soluble constituents (BCSCs) and simultaneously nourished with culture medium flowing beneath the permeable PC membranes. The ALI-DC method was compared with the traditional submerged culture approach. BCSC particle morphology and dosages deposited on the chip were determined for particle characterization. Flow cytometry, scanning electron microscopy, and transmission electron microscopy were used to investigate the apoptosis rate of HPAEpiC and changes in the cell ultrastructure induced by BCSCs. Additionally, the underlying apoptotic pathway was examined by determining the protein expression levels by western blotting.

RESULTS

Scanning electron microscope images demonstrated that the sample processing and delivering approach of the ALI-DC platform were suitable for pollutant exposure. Compared with the submerged culture method, a significant decline in cell viability and increase in apoptosis rate was observed after BCSC exposure on the ALI-DC platform, indicating that the ALI-DC platform is a more sensitive system for investigating cytotoxicity of indoor air pollutants in lung cells. The morphology and ultrastructure of the cells were damaged after exposure to BCSCs, and the p53 pathway was activated. The Bcl-2/Bax ratio was reduced, upregulating caspase-9 and caspase-3 expression and subsequently inducing apoptosis of HPAEpiC. The addition of N-acetyl cysteine antioxidant significantly alleviated the cytotoxicity induced by BCSCs.

CONCLUSION

A novel ALI-DC platform was developed to study the cytotoxicity of air pollutants on lung cells. Using the platform, we demonstrated that BCSCs could damage the mitochondria, produce reactive oxygen species, and activate p53 in HPAEpiC, ultimately inducing apoptosis.

Health impacts of indoor air pollution from household solid fuel on children and women

The inefficient and incomplete combustion of solid fuel (SF) is associated with high levels of indoor air pollutants leading to 3.55 million deaths annually. The risk is higher in women and children, due to their higher exposure duration and unique physical properties. The current article aims to provide a critical overview regarding the use of solid fuel, its associated pollutants, their toxicity mechanisms and, most importantly the associated health impacts, especially in women and children. Pollutants associated with SF mostly include polycyclic aromatic hydrocarbons, particulate matter, nitrous oxide, carbon monoxide and sulfur dioxide, and their concentrations are two- to threefold higher in indoor environments. These pollutants can lead to a variety of health risks by inducing different toxicity mechanisms, such as oxidative stress, DNA methylation, and gene activation. Exposed children have an increased prevalence of low birth weight, acute lower respiratory tract infections, anemia and premature mortality. On the other hand, lung cancer, chronic obstructive pulmonary disease and cardiovascular diseases are the major causes of disability and premature death in women. Indoor air pollution resulting from SF combustion is a major public health threat globally. To reduce the risks, it is important to identify future research gaps and implement effective interventions and policies.

Effects of a Household Air Pollution Intervention with Liquefied Petroleum Gas on Cardiopulmonary Outcomes in Peru. A Randomized Controlled Trial

Rationale: Approximately 40% of people worldwide are exposed to household air pollution (HAP) from the burning of biomass fuels. Previous efforts to document health benefits of HAP mitigation have been stymied by an inability to lower emissions to target levels. Objectives: We sought to determine if a household air pollution intervention with liquefied petroleum gas (LPG) improved cardiopulmonary health outcomes in adult women living in a resource-poor setting in Peru. Methods: We conducted a randomized controlled field trial in 180 women aged 25-64 years living in rural Puno, Peru. Intervention women received an LPG stove, continuous fuel delivery for 1 year, education, and behavioral messaging, whereas control women were asked to continue their usual cooking practices. We assessed for stove use adherence using temperature loggers installed in both LPG and biomass stoves of intervention households. Measurements and Main Results: We measured blood pressure, peak expiratory flow (PEF), and respiratory symptoms using the St. George's Respiratory Questionnaire at baseline and at 3-4 visits after randomization. Intervention women used their LPG stove exclusively for 98% of days. We did not find differences in average postrandomization systolic blood pressure (intervention - control 0.7 mm Hg; 95% confidence interval, -2.1 to 3.4), diastolic blood pressure (0.3 mm Hg; -1.5 to 2.0), prebronchodilator peak expiratory flow/height² (0.14 L/s/m²; -0.02 to 0.29), postbronchodilator peak expiratory flow/height² (0.11 L/s/m²; -0.05 to 0.27), or St. George's Respiratory Questionnaire total score (-1.4; -3.9 to 1.2) over 1 year in intention-to-treat analysis. There were no reported harms related to the intervention. Conclusions: We did not find evidence of a difference in blood pressure, lung function, or respiratory symptoms during the year-long intervention with LPG. Clinical trial registered with www.clinicaltrials.gov (NCT02994680).

Relation between occupants' health problems, demographic and indoor environment subjective evaluations: A cross-sectional questionnaire survey study in Java Island, Indonesia

This study aimed to evaluate the link between health problems, demographic factors, and the indoor environment quality of residents in Indonesia. We conducted a cross-sectional design study through a questionnaire survey with 443 respondents aged between 12 and 81 years. The questionnaire was concerned with previous health problem occurrences associated with thermal discomfort experiences, indoor environments, economic conditions, and basic anthropometric factors. Logistic regression with the odds ratio (OR) was applied to evaluate the tendency of different respondent groups to suffer from certain health problems, when compared to reference groups. Furthermore, structural equation modelling (SEM) was used to incorporate certain factors (economic conditions, thermal discomfort experiences, and perceived indoor environments) into a single model to understand their direct and indirect effects on health conditions. The results indicate that economic conditions are the most significantly associated with health problems. Furthermore, we found that the low-income group was the most vulnerable to health problems, including coughing, puking, diarrhoea, odynophagia, headaches, fatigue, rheumatism, fidgeting, skin rashes, muscle cramps, and insomnia (OR: 1.94-6.04, p <0.05). Additionally, the SEM suggested that the respondents' economic conditions and thermal discomfort experiences had significant direct effects on their health problems with standardized estimates of -0.29 and 0.55, respectively. Additionally, perceived indoor environment quality, which is possible to cause thermal discomfort experience, indirectly affect health problems. These findings contribute an insightful and intuitive knowledge base which can aid health assessments associated with demographic and physical environments in developing sustainable and healthy environment strategies for the future.

Volatile Organic Compounds (VOCs) Emitted from Coated Furniture Units

Volatile organic compounds (VOCs) are the main source influencing the overall air quality of an environment. It is a well-known fact that coated furniture units, in the form of paints and varnishes, emit VOCs, reducing the air quality and resulting in significant health problems. Exposure time to such compounds is also an important parameter regarding their possible health effects. Such issues also have a greater influence when the exposure period is extended. The main objective of this study was to review some of the important factors for the emission of VOCs from coated furniture, from the perspective of material characteristics, as well as health concerns. Some methods for controlling VOC emissions to improve indoor air quality, from the point of view recent regulations and suggestions, are also presented in this work.

Liquid crystal display screens as a source for indoor volatile organic compounds

Liquid crystal displays (LCDs) have profoundly shaped the lifestyle of humans. However, despite extensive use, their impacts on indoor air quality are unknown. Here, we perform flow cell experiments on three different LCDs, including a new computer monitor, a used laptop, and a new television, to investigate whether their screens can emit air constituents. We found that more than 30 volatile organic compounds (VOCs) were emitted from LCD screens, with a total screen area-normalized emission rate of up to (8.25 ± 0.90) × 10⁹ molecules ⋅ s^-1 ⋅ cm^-2 In addition to VOCs, 10 liquid crystal monomers (LCMs), a commercial chemical widely used in LCDs, were also observed to be released from those LCD screens. The structural identification of VOCs is based on a "building block" hypothesis (i.e., the screen-emitted VOCs originate from the "building block chemicals" used in the manufacturing of liquid crystals), which are the key components of LCD screens. The identification of LCMs is based upon the detailed information of 362 currently produced LCMs. The emission rates of VOCs and LCMs increased by up to a factor of 9, with an increase of indoor air humidity from 23 to 58% due to water-organic interactions likely facilitating the diffusion rates of organics. These findings indicate that LCD screens are a potentially important source for indoor VOCs that has not been considered previously.

Using Crowd-Sourced Data to Assess the Temporal and Spatial Relationship between Indoor and Outdoor Particulate Matter

Using hourly measures across a full year of crowd-sourced data from over 1000 indoor and outdoor pollution monitors in the state of California, we explore the temporal and spatial relationship between outdoor and indoor particulate matter (PM) concentrations for different particle sizes. The scale of this study offers new insight into both average penetration rates and drivers of heterogeneity in the outdoor-indoor relationship. We find that an increase in the daily outdoor PM concentration of 10% leads to an average increase of 4.2-6.1% in indoor concentrations. The penetration of outdoor particles to the indoor environment occurs rapidly and almost entirely within 5 h. We also provide evidence showing that penetration rates are associated with building age and climatic conditions in the vicinity of the monitor. Since people spend a substantial amount of each day indoors, our findings fill a critical knowledge gap and have significant implications for government policies to improve public health through reductions in exposure to ambient air pollution.

The impact of air pollution on skin and related disorders: A comprehensive review

As the largest organ in the body, human skin is constantly exposed to harmful compounds existing in the surrounding environment as the first-line barrier. Studies have indicated that exposure to high concentrations of many environmental factors, such as ultraviolet (UV) radiation, outdoor air pollutants, including polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), particulate matter (PM), heavy metals, gaseous pollutants, such as carbon monoxide (CO), nitric oxides (NO_x ), sulfur oxide (SO₂ ), ozone (O₃ ), and indoor air pollutants (solid fuels consumption), might interrupt the skin's normal barrier function. Besides, the intensity of the pollutants and the length of exposure might be a contributing factor. Air pollutants are believed to induce or exacerbate a range of skin conditions, such as aging, inflammatory diseases (atopic dermatitis, cellulitis, and psoriasis), acne, hair loss, and even skin cancers (mainly melanoma and Squamous Cell Carcinoma) through various mechanisms. The interaction between pollutants and the skin might differ based on each agent's particular characteristics. Also, damaging the skin barrier seems to be closely related to the increased production of reactive oxygen species (ROS), induction of oxidative stress, activation of aryl hydrocarbon receptor (AhR), and inflammatory cytokines. This article reviews recent studies on the correlation between air pollutants and skin diseases, along with related mechanisms.

Sub-multiplicative interaction between polygenic risk score and household coal use in relation to lung adenocarcinoma among never-smoking women in Asia

We previously identified 10 lung adenocarcinoma susceptibility loci in a genome-wide association study (GWAS) conducted in the Female Lung Cancer Consortium in Asia (FLCCA), the largest genomic study of lung cancer among never-smoking women to date. Furthermore, household coal use for cooking and heating has been linked to lung cancer in Asia, especially in Xuanwei, China. We investigated the potential interaction between genetic susceptibility and coal use in FLCCA. We analyzed GWAS-data from Taiwan, Shanghai, and Shenyang (1472 cases; 1497 controls), as well as a separate study conducted in Xuanwei (152 cases; 522 controls) for additional analyses. We summarized genetic susceptibility using a polygenic risk score (PRS), which was the weighted sum of the risk-alleles from the 10 previously identified loci. We estimated associations between a PRS, coal use (ever/never), and lung adenocarcinoma with multivariable logistic regression models, and evaluated potential gene-environment interactions using likelihood ratio tests. There was a strong association between continuous PRS and lung adenocarcinoma among never coal users (Odds Ratio (OR) = 1.69 (95% Confidence Interval (CI) = 1.53, 1.87), p=1 × 10-26). This effect was attenuated among ever coal users (OR = 1.24 (95% CI: 1.03, 1.50), p = 0.02, p-interaction = 6 × 10-3). We observed similar attenuation among coal users from Xuanwei. Our study provides evidence that genetic susceptibility to lung adenocarcinoma among never-smoking Asian women is weaker among coal users. These results suggest that lung cancer pathogenesis may differ, at least partially, depending on exposure to coal combustion products. Notably, these novel findings are among the few instances of sub-multiplicative gene-environment interactions in the cancer literature.

Mitigation of indoor air pollutants using Areca palm potted plants in real-life settings

Deterioration of indoor air quality (IAQ) has become a serious concern as people spend lots of time indoors and prolonged pollution exposure can result in adverse health outcomes. Indoor plants can phytoremediate a wide variety of indoor contaminants. Nonetheless, few experiments have demonstrated their efficacy in real-time environments. Therefore, the present study aims to experimentally assess the efficiency of Areca palm potted plants in phytoremediation of primary indoor air pollutant viz. total volatile organic compounds (TVOCs), carbon dioxide (CO₂), and carbon monoxide (CO) levels from real-world indoor spaces, for the first time. Four discrete naturally ventilated experimental sites (I-IV) situated at the Council of Scientific and Industrial Research- Institute of Himalayan Bioresource Technology (CSIR-IHBT) were used. For over a period of 4 months, the sites were monitored using zero plants as a control (1-4 week), three plants (5-8 week), six plants (9-12 week), and nine plants (13-16 week), respectively. Present results indicate that Areca palm potted plants can effectively reduce the TVOCs, CO₂, and CO levels by 88.16% in site IV, 52.33% and 95.70% in site III, respectively. The current study concluded that Areca palm potted plants offer an efficient, cost-effective, self-regulating, sustainable solution for improving indoor air quality and thereby human well-being and productivity in closed and confined spaces.

How Is Indoor Air Quality during Sleep? A Review of Field Studies

This review aimed to provide an overview of the characterisation of indoor air quality (IAQ) during the sleeping period, based only on real life conditions’ studies where, at least, one air pollutant was considered. Despite the consensual complexity of indoor air, when focusing on sleeping environments, the available scientific literature is still scarce and falls to provide a multipollutants’ characterisation of the air breathed during sleep. This review, following PRISMA’s approach, identified a total of 22 studies that provided insights of how IAQ is during the sleeping period in real life conditions. Most of studies focused on carbon dioxide (77%), followed by particles (PM2.5, PM10 and ultrafines) and only 18% of the studies focused on pollutants such as carbon monoxide, volatile organic compounds and formaldehyde. Despite the high heterogeneity between studies (regarding the geographical area, type of surrounding environments, season of the year, type of dwelling, bedrooms’ ventilation, number of occupants), several air pollutants showed exceedances of the limit values established by guidelines or legislation, indicating that an effort should be made in order to minimise human exposure to air pollutants. For instance, when considering the air quality guideline of World Health Organisation of 10 µg·m−3 for PM2.5, 86% of studies that focused this pollutant registered levels above this threshold. Considering that people spend one third of their day sleeping, exposure during this period may have a significant impact on the daily integrated human exposure, due to the higher amount of exposure time, even if this environment is characterised by lower pollutants’ levels. Improving the current knowledge of air pollutants levels during sleep in different settings, as well as in different countries, will allow to improve the accuracy of exposure assessments and will also allow to understand their main drivers and how to tackle them.

Evaluation of particulate matter concentrations according to cooking activity in a residential environment

This study aimed to determine the ventilation conditions required for suitable indoor air quality management during cooking in a typical South Korean residential home. We measured the concentrations of particulate matter (PM₁₀) and fine particulate matter (PM_2.5) under different ventilation conditions during the cooking of different food materials in the kitchen of a multi-family house, which is the representative residential space in South Korea. Pork belly and mackerel, which are the staple meat and fish products of Korean people, were prepared (200 g of each) and cooked via roasting. The PM₁₀ and PM_2.5 concentrations were measured three times for 1 h at 1 min intervals under twelve ventilation conditions. To investigate the PM₁₀ and PM_2.5 concentration distribution characteristics and the reduction effect according to ventilation condition, the ratio of the concentration during cooking to the initial concentration was calculated for each condition. Factors causing the emission of PM₁₀ and PM_2.5 for each food material and under each ventilation condition were analyzed using principal component analysis and verified using one-way analysis of variance and post hoc analysis. The PM₁₀ and PM_2.5 concentrations generated during the cooking of pork belly and mackerel reached their maximum values when no ventilation was used. Under this condition, PM₁₀ concentrations were 246.27 and 1227.71 μg/m³ while the PM_2.5 concentrations were 161.93 and 760.82 μg/m³ for pork belly and mackerel cooking, respectively. The PM₁₀ and PM_2.5 concentrations were also found to be high when a range hood and air cleaner were used, indicating that it is necessary to improve the performance of ventilation devices and to use appropriate ventilation methods. The use of natural ventilation exhibited a high PM₁₀ and PM_2.5 reduction effect compared with the ventilation conditions that used ventilation devices. Using natural ventilation together with ventilation devices was found to be the most effective method of reducing the PM₁₀ and PM_2.5 generated during cooking. In conclusion, PM₁₀ and PM_2.5 concentrations generated during the cooking of pork belly and mackerel varied depending on the ventilation condition, but they were high when inappropriate ventilation methods were used. Therefore, using appropriate ventilation conditions is effective in reducing PM₁₀ and PM_2.5 generated during cooking.

Association between household solid fuel use and tuberculosis: cross-sectional data from the Mongolian National Tuberculosis Prevalence Survey

BACKGROUND

Tuberculosis (TB) and indoor air pollution (IAP) are equally critical public health issues in the developing world. Mongolia is experiencing the double burden of TB and IAP due to solid fuel combustion. However, no study has assessed the relationship between household solid fuel use and TB in Mongolia. The present study aimed to assess the association between household solid fuel use and TB based on data from the Mongolian National Tuberculosis Prevalence Survey (MNTP Survey).

METHOD

The MNTP Survey was a nationally representative population-based cross-sectional survey targeting households in Mongolia from 2014 to 2015, with the aim of evaluating the prevalence of TB. The survey adopted a multistage cluster sampling design in accordance with the World Health Organization prevalence survey guidelines. Clusters with at least 500 residents were selected by random sampling. A sample size of 98 clusters with 54,100 participants was estimated to be required for the survey, and 41,450 participants were included in the final analysis of the present study. A structured questionnaire was used to collect information on environmental and individual factors related to TB. Physical examination, chest X-ray, and sputum examinations were also performed to diagnose TB.

RESULTS

The use of solid fuels for heating (adjusted odds ratio (aOR): 1.5; 95% confidence interval (CI): 1.1-2.1), male gender (aOR: 2.2; 95% CI: 1.6-3.2), divorced or widowed (aOR: 2.6; 95% CI: 1.7-3.8), daily smoker (aOR: 1.8; 95% CI: 1.3-2.5), contact with an active TB case (aOR: 1.7; 95% CI: 1.2-2.3), being underweight (aOR: 3.7; 95% CI: 2.4-5.7), and previous history of TB (aOR: 4.3; 95% CI: 3.0-6.1) were significantly associated with bacteriologically confirmed TB after adjusting for confounding variables.

CONCLUSION

The use of solid fuels for heating was significantly associated with active TB in Mongolian adults. Increased public awareness is needed on the use of household solid fuels, a source of IAP.

Critical warning! Preventing the multidimensional apocalypse on planet Earth

Intensified human activities are causing ever-growing threats to biodiversity, including humans and ecosystem services. Conversely, evidence showing the multiple benefits and socio-economic values of ecosystem services and goods is increasing substantially. A fundamental societal revolution is urgently needed to preserve the health of populations of living beings, communities and ecosystems. The present article aims to convey that the multidimensional (sanitary, social, economic, political, ecological and ideological) crisis we are facing should force us to build bridges and exchanges between science, the public and politics - an essential prerequisite to implement coherent and sustainable biodiversity, public health and education policies on both local and global scales.

Comparison of Liquefied Petroleum Gas Cookstoves and Wood Cooking Fires on PM2.5 Trends in Brick Workers' Homes in Nepal

Prior studies document a high prevalence of respiratory symptoms among brick workers in Nepal, which may be partially caused by non-occupational exposure to fine particulate matter (PM2.5) from cooking. In this study, we compared PM2.5 levels and 24 h trends in brick workers' homes that used wood or liquefied petroleum gas (LPG) cooking fuel. PM2.5 filter-based and real-time nephelometer data were collected for approximately 24 h in homes and outdoors. PM2.5 was significantly associated with fuel type and location (p < 0.0001). Pairwise comparisons found significant differences between gas, indoor (geometric mean (GM): 79.32 μg/m3), and wood, indoor (GM: 541.14 μg/m3; p = 0.0002), and between wood, indoor, and outdoor (GM: 48.38 μg/m3; p = 0.0006) but not between gas, indoor, and outdoor (p = 0.56). For wood fuel homes, exposure peaks coincided with mealtimes. For LPG fuel homes, indoor levels may be explained by infiltration of ambient air pollution. In both wood and LPG fuel homes, PM2.5 levels exceeded the 24 h limit (25.0 µg/m3) proposed by the World Health Organization. Our findings suggest that increasing the adoption of LPG cookstoves and decreasing ambient air pollution in the Kathmandu valley will significantly lower daily PM2.5 exposures of brick workers and their families.

Fungal Contaminants in Energy Efficient Dwellings: Impact of Ventilation Type and Level of Urbanization

The presence of growing fungi in the indoor environment has been associated with the development of respiratory problems such as asthma or allergic rhinitis, as well as the worsening of respiratory pathologies. Their proliferation indoors could be a result of water leakage or inadequate ventilation. Although the factors promoting mould growth have been widely investigated in traditional dwellings, little work has been done in energy efficient dwellings. Here, the effectiveness of ventilation type, i.e., natural or mechanical, in influencing mould development was estimated in 44 recent and 105 retrofitted energy efficient dwellings. Fungi growing on surfaces were investigated in the dwellings situated in rural, peri-urban, and urban regions of Switzerland. The presence of these fungi was also investigated in bedroom settled dust. Information on building characteristics and owners' lifestyle were collected. Significant associations were found with the level of urbanisation, the location of mouldy area in dwellings, and the diversity of fungal taxa. Dwellings in peri-urban zones showed the most frequent fungal contamination in the owners' bedroom and the highest diversity of fungal genera among dwellings. While the urbanisation level or the ventilation type favoured no specific genus, we found marked disparities in the diversity of fungi growing on surfaces in naturally ventilated versus mechanically ventilated dwellings. Aspergillus, in particular, was a frequent surface contaminant in bedrooms with natural ventilation, but not in those mechanically ventilated. We observed a strong association between fungal growth on surfaces and the number of fungal particles counted in the settled dust of owners' bedrooms. These results demonstrate the importance of ventilation systems in energy efficient dwellings in controlling fungal proliferation in living areas.

Significant ultrafine particle emissions from residential solid fuel combustion

When addressing particulate matter (PM) emissions from residential solid fuel combustion, ultrafine particles are usually merged into PM_2.5, while whose mass concentration is applied as the index in evaluating PM pollution as well as assessing PM-induced health risk. This may not effectively represent the risk from ultrafine particles. In this study, we explored ultrafine particle emissions during residential combustion under both laboratory-controlled and real-world rural household conditions. Significant ultrafine particle emissions (i.e. with emission factors between 2 × 10¹⁵ to 2 × 10¹⁶ particles per kg of fuel) are found for both coal and biomass. High emissions of particle mass concentration often occur at the beginning of the combustion (i.e. the first 30 min after fire start) while high emissions of particle number concentration occur in a later combustion period (60-150 min). Ultrafine particles account for over 90% of the emitted total particle number concentration from 3 nm to 10 μm. These emissions elevate ultrafine particle number concentration by more than a decade in indoor environment under which household residents are directly exposed. In addition, we show that there is notable inconsistency between reducing PM_2.5 mass based emissions and reducing ultrafine particle number based emissions among various control strategies that were proposed for reducing pollution from residential combustion. Both "cleaner" fuels and stoves that are designed to reduce PM_2.5 emissions are found to be not necessarily effective in reducing ultrafine particle emissions, even increase their emissions in some cases. These findings indicate that the overlook of ultrafine particle emissions from residential solid fuel combustion can lead to potential health risk to household residents, especially to those vulnerable ones (e.g., the elderly and children) who are more sensitive to indoor air pollution. More attentions are needed on ultrafine particle pollution and its potential health risk in comparison to using the PM mass concentration index alone.