Formaldehyde and volatile organic compounds in Hong Kong homes: concentrations and impact factors

Association Between Home Renovation and Sleeping Problems Among Children Aged 6-18 Years: A Nationwide Survey in China

BACKGROUND

Although the indoor environment has been proposed to be associated with childhood sleep health, to our knowledge no study has investigated the association between home renovation and childhood sleep problems.

METHODS

The study included 186,470 children aged 6-18 years from the National Chinese Children Health Study (2012-2018). We measured childhood sleeping problems via the Chinese version of the Sleep Disturbance Scale for Children (C-SDSC). Information on home renovation exposure within the recent 2 years was collected via parent report. We estimated associations between home renovation and various sleeping problems, defined using both continuous and categorized (binary) C-SDSC t-scores, using generalized mixed models. We fitted models with city as a random effect variable, and other covariates as fixed effects.

RESULTS

Out of the overall participants, 89,732 (48%) were exposed to recent home renovations. Compared to the unexposed group, children exposed to home renovations had higher odds of total sleep disorder (odd ratios [OR] = 1.3; 95% confidence interval [CI] = 1.2, 1.4). Associations varied when we considered different types of home renovation materials. Children exposed to multiple types of home renovation had higher odds of sleeping problems. We observed similar findings when considering continuous C-SDSC t-scores. Additionally, sex and age of children modified the associations of home renovation exposure with some of the sleeping problem subtypes.

CONCLUSIONS

We found that home renovation was associated with higher odds of having sleeping problems and that they varied when considering the type of renovation, cumulative exposure, sex, and age differences.

Indoor air quality and its determinants in underground shopping malls in Korea

Underground shopping malls (USMs) are often open or semi-open environments with interconnected passageways, resulting in the sharing of indoor air. However, indoor air quality (IAQ) within these spaces can vary due to many diverse emission sources. We investigated the relationships between IAQ and geographical areas, as well as IAQ and store types, within USMs, in Korea. In 2020, we studied 10 different USMs, with a total of 128 outlets. We conducted comprehensive IAQ assessments (including measurements of fine particles (PM2.5), aldehydes, and volatile organic compounds (VOCs)) in stores, passages, and outdoor areas. The stores were categorized into three types: clothing, fashion accessories, and food services. Additionally, we measured environmental factors such as CO2 levels and presence of storefront walls. PM2.5 levels were higher outdoors, whereas aldehyde and VOC levels exhibited elevations within passages and the interior of stores than in the outdoor environment. The store-to-passage ratios for PM2.5, individual aldehydes, and VOC concentrations ranged from 1.06 to 4.93. Formaldehyde and total VOC (TVOC) concentrations were found to be elevated in clothing and fashion accessory stores, whereas PM2.5 concentrations were more prominent in food service establishments. Specific individual compounds, including propionaldehyde, hexaldehyde, benzene, n-heptane, toluene, n-octane, xylene, d-limonene, n-undecane, n-dodecane, and ethylbenzene concentrations exhibited associations with store types. Multivariate regression models demonstrated positive associations between most aldehydes and VOCs with CO2 concentrations and presence of storefront walls. This study underscored variations within USMs based on area and store type. Aldehyde and VOC concentrations were notably higher in clothing and fashion accessory stores than in food service outlets; these elevations were closely linked to CO2 levels and presence of storefront walls. These findings suggest that monitoring CO2 levels within USM stores, optimizing air-conditioning systems, and designing future stores without storefront walls can collectively contribute to an overall improvement of IAQ within USMs.

Electrochemical removal of gaseous benzene using a flow-through reactor with efficient and ultra-stable titanium suboxide/titanium-foam anode at ambient temperature

Catalytic oxidation technology is currently considered as a feasible approach to degrade and mineralize volatile organic compounds (VOCs). However, it is still challenging to realize efficient removal of VOCs through catalytic oxidation at room temperature. In our study, a novel flow-through electrocatalytic reactor was designed, composed of porous solid-electrolyte, gas-permeable titanium sub-oxides/titanium-foam (TiSO/Ti-foam) as anode and platinum coated titanium foam (Pt/Ti-foam) as cathode. This device could oxidize nearly 100% of benzene (10 ppm) to carbon dioxide at a current density of 1.2 mA/cm² under room temperature. More importantly, the device maintained excellent stability over 1000 h. Mechanism of benzene mineralization was discussed. Hydroxyl radicals generated on the TiSO/Ti-foam anode played a crucial role in the oxidation of benzene. This study provides a promising prototype of the electrochemical air purifier, and may find its application in domestic and industrial air pollution control.

The Association Between Self-Reported Household Renovation and Semen Parameters Among Infertile Men: A Cross-Sectional Study

Previous studies have indicated that outdoor air pollution has a negative impact on semen quality; however, few studies have examined whether living in a recently renovated residence is one of the factors influencing semen parameters. We aimed to examine the association between household renovation and semen parameters among infertile men. Our study was conducted at the Reproductive Medicine Center, The First Hospital of Jilin University (Changchun, China) from July 2018 to April 2020. A total of 2267 participants were enrolled in the study. The participants completed the questionnaire and provided a semen sample. Univariate and multiple logistic regression models were used to estimate the association between household renovations and semen parameters. Of the participants, about one-fifth (n = 523, 23.1%) had undergone renovations in the last 24 months. The median progressive motility was 34.50%. There was a significant difference between participants whose residences had been renovated in the last 24 months and those whose residences had not been recently renovated (z = -2.114, p = .035). Compared with participants whose residences were not recently renovated, participants who moved into the residence within 3 months after renovation had a higher risk of abnormal progressive motility after adjusting for age and abstinence time (odds ratio [OR] = 1.537, 95% confidence interval [CI]: 1.088-2.172). Our findings indicated that progressive motility was significantly associated with household renovations.

Associations between home renovation and asthma, allergic rhinitis, and eczema among preschool children in Wuhan, China

To investigate the potential associations between household renovation and allergic diseases among preschool children in Wuhan, we conducted a large cross-sectional questionnaire survey among 9455 preschool children aged 3-6 years in Wuhan during November to December 2019. Data on demographics, health status, and home decoration conditions were analysed based on a questionnaire. Compared with tiles/stone/cement floor covering, the use of composite floor significantly increased the risk of diagnosed rhinitis and eczema among children (rhinitis: AOR, 95% CI: 1.36, 1.06-1.73; eczema: AOR, 95% CI: 1.47, 1.17-1.85). Household renovation had significant associations with diagnosed eczema (within 1 year before pregnancy: AOR, 95% CI: 1.34, 1.20-1.50; during pregnancy: AOR, 95% CI: 1.25, 1.08-1.44). This study suggests that use of artificial synthetic materials in home renovation during early childhood and pregnancy may be potential risk factors for childhood asthma, allergic rhinitis, and eczema.

TVOC - Revisited

BACKGROUND

TVOC (total volatile organic compounds) has been used as a sum parameter in indoor air sciences for over 40 years. In the beginning, individual VOC concentrations determined by gas chromatography were simply added together. However, several methods for calculating TVOC have become established over time.

METHODS

To understand the manifold definitions of TVOC, one must trace the history of indoor air sciences and analytical chemistry. Therefore, in this work, the original approaches of TVOC are searched and explained. A detailed description of the measurement methods is followed by a critical evaluation of the various TVOC values and their possible applications. The aim is to give the reader a deeper understanding of TVOC in order to use this parameter correctly and to be able to better assess published results. In addition, related sum values such as TSVOC and TVVOC are also addressed.

RESULTS

A milestone was the analytical definition of VOCs and TVOC in 1997. A list of VOCs that should at least be considered when calculating TVOC was also provided. This list represented the status at that time, is no longer up-to-date and is being updated by a European working group as part of a harmonization process. However, there is still confusion about the exact definition and reasonable application of TVOC. The signals of other sum parameters, measured with photoacoustics, flame ionization, photoionization or electrochemical sensors, are also often given under the term TVOC.

CONCLUSIONS

It was recognized early that TVOC is not a toxicologically based parameter and is therefore only suitable for a limited number of screening purposes. Consequently, TVOC cannot be used in connection with health-related and odor-related issues. Nevertheless, such references are repeatedly made, which has led to controversial scientific discussions and even court decisions in Germany about the correct and improper use of TVOC.

Indoor exposure levels and risk assessment of volatile organic compounds in residences, schools, and offices in China from 2000 to 2021: A systematic review

The last two decades have witnessed rapid urbanization and economic growth accompanied by severe indoor air pollution of volatile organic compounds (VOCs) in China. However, indoor VOC pollution across China has not been well characterized and documented. This study is a systematic review of field measurements of eight target VOCs (benzene, toluene, xylenes, acetaldehyde, p-dichlorobenzene, butadiene, trichloroethylene, and tetrachloroethylene) in residences, offices, and schools in China from 2000 to 2021. The results show that indoor pollution of benzene, toluene, and xylenes has been more serious in China than in other countries. Spatiotemporal distribution shows lower indoor VOC levels in east and south-east regions and a declining trend from 2000 to 2021. Moving into a dwelling more than 1 year after decoration and improving ventilation could significantly reduce exposure to indoor VOCs. Reducing benzene exposure is urgently needed because it is associated with greater health risks (4.5 × 10^-4 for lifetime cancer risk and 8.3 for hazard quotient) than any other VOCs. The present study enriches the database of indoor VOC levels and provides scientific evidence for improving national indoor air quality standards as well as estimating the attributable disease burden caused by VOCs in China.

Volatile organic compounds from second-hand smoke may increase susceptibility of children through oxidative stress damage

Although humans are generally exposed to second-hand smoke (SHS), volatile organic compounds (VOCs) exposure derived from SHS and its health hazard to non-smokers are rarely investigated. Thus, we examined the effects of SHS on VOCs exposure and oxidative stress damage via a passive smoking simulation experiment in 6 children and 7 adults. To further validate the studied urinary VOC metabolites as biomarkers for passive smoking, 259 children were recruited. The levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), malonaldehyde (MDA), trans-3'-hydroxycotinine (OH-Cot) and 31 VOC metabolites in urine were determined. The results showed that the geomean concentrations of 17 VOC metabolites in urine of children were 26.5%-138% higher than those of adults after passive smoking. The levels of urinary 8-OHdG, MDA and OH-Cot increased by 24.6%, 18.8% and 600% in children, but only 1.25%, 10.3% and 116% in adults, respectively. Therefore, children are more vulnerable to SHS than adults. After exposure to SHS, the levels of 8 urinary VOC metabolites of benzene, acrylonitrile, 1-bromopropane, propylene oxide, toluene, methyl methacrylate and cyanide increased by 60.9%-538% within 23 h. These 8 VOC metabolites were also significantly associated with 8-OHdG or MDA in urine (p < 0.01). Therefore, exposure to VOCs caused by SHS increases body oxidative stress damage. OH-Cot level higher than 2.00 μg/g Cr can be used as a threshold of passive smoking. The levels of urinary s-benzylmercapturic acid (BMA) and s-phenylmercapturic acid (PMA) in children increased by 494% and 728% within 6 h after passive smoking, respectively. Population validation study indicated that BMA and PMA levels were significantly elevated in children exposed to SHS. Therefore, in addition to OH-Cot, urinary BMA and PMA are potentially useful short-term biomarkers of passive smoking. Future studies should focus on the differences in VOC metabolism and detoxification mechanisms between children and adults.

Emission characteristics, sources, and airborne fate of speciated organics in particulate matters in a Hong Kong residence

A growing number of studies warn of the adverse health effects of indoor particulate matters (PM). However, little is known about the molecular compositions and emission characteristics of PM-bound organics (OM) indoors, a critical group of species with highest concentration and complexity in indoor PM. In a Hong Kong residence where prescribed activities were performed with normal frequency and intensity, we found that the activities significantly elevated not only the total concentration but also the fraction of OM in indoor PM. However, the concentration of the total PM-bound OM outdoors (10.3 ± 0.7 μg/m³ ) surpassed that for the indoor counterpart during the undisturbed period (8.2 ± 0.1 μg/m³ ), that is, period when there was no activity with high emission of PM but the residual effects of previous activities might remain. Emissions of indoor activities involving combustion or high-temperature processes significantly elevated the indoor-to-outdoor (I/O) ratios for a majority of organic species. In addition, gas-to-particle partitioning, secondary formation, carrying-over (residues of pollutants in the air), and re-emission also modulated the I/O ratios of some compounds. Chemically comprehensive emission profiles of speciated organics were obtained for 5 indoor activities in the residence. While the indoor contribution to PM-bound OM was estimated to be not higher than 13.1% during the undisturbed period, carrying-over and/or re-emission seemed to exist for certain compounds emitted from cigarette smoking and incense burning. This study enhances knowledge on emissions and airborne fate of speciated organics in indoor PM.

A Study on the Measurement of Unregulated Pollutants in Korean Residential Environments

This study investigated the pollution caused by unregulated chemical substances in Korean residential environments. A TA tube was used for indoor air collection, and Gas Chromatography–Mass Spectrometry was used for the analysis of chemical substances. According to the results of this study, 13 substances out of the 16 analyzed chemicals were detected and, among them, the concentrations of phenol, α-pinene, and limonene within the indoor air were high. The average concentration of phenol was 32.7 µg/m3. α-pinene and limonene were detected, of which the highest concentrations were as 598.2 µg/m3 and 652.5 µg/m3, respectively. The maximum concentrations of these three substances exceeded the levels of the lowest concentration of interest. Notably, α-pinene and limonene were released from the wood itself. Wood has been widely used indoors as a natural building material and as furniture. Therefore, it was considered that this was the reason for the high the concentrations of the two substances in indoor air. However, we do not argue that the usage of wood should be reduced because of the results obtained in this study. Instead, we sµggest that it is important to reduce the emissions of α-pinene and limonene throµgh the processing of the wood, extending its drying period, and determining the most appropriate time of use.

Indoor Air Quality in Healthcare and Care Facilities: Chemical Pollutants and Microbiological Contaminants

The indoor air quality of healthcare and care facilities is poorly studied. The aim of this study was to qualitatively and quantitatively describe the chemical pollution and the microbiological contaminations of the indoor environment of these facilities. Methods: A wide range of chemical compounds (39 volatile and 13 semi-volatile organic compounds, carbon dioxide, fine particulate matter) and microorganisms (fungi and bacteria) were studied. Sampling campaigns were conducted in two French cities in summer 2018 and winter 2019 in six private healthcare facilities (general practitioner’s offices, dental offices, pharmacies) and four care facilities (nursing homes). Results: The highest median concentrations of chemical compounds (μg/m3) were measured for alcohols (ethanol: 378.9 and isopropanol: 23.6), ketones (acetone: 18.8), aldehydes (formaldehyde: 11.4 and acetaldehyde: 6.5) and terpenes (limonene: 4.3). The median concentration of PM2.5 was 9.0 µg/m3. The main bacteria of these indoor environments were Staphylococcus, Micrococcus and Bacillus genera, with median bacterial concentrations in the indoor air of 14 cfu/m3. The two major fungal genera were Cladosporium and Penicillium, with median fungal concentrations of 7 cfu/m3. Conclusions: Indoor air in healthcare and care facilities contains a complex mixture of many pollutants found in higher concentrations compared to the indoor air in French hospitals in a previous study.

Real-time molecular characterization of air pollutants in a Hong Kong residence: Implication of indoor source emissions and heterogeneous chemistry

Due to the high health risks associated with indoor air pollutants and long-term exposure, indoor air quality has received increasing attention. In this study, we put emphasis on the molecular composition, source emissions, and chemical aging of air pollutants in a residence with designed activities mimicking ordinary Hong Kong homes. More than 150 air pollutants were detected at molecular level, 87 of which were quantified at a time resolution of not less than 1 hour. The indoor-to-outdoor ratios were higher than 1 for most of the primary air pollutants, due to emissions of indoor activities and indoor backgrounds (especially for aldehydes). In contrast, many secondary air pollutants exhibited higher concentrations in outdoor air. Painting ranked first in aldehyde emissions, which also caused great enhancement of aromatics. Incense burning had the highest emissions of particle-phase organics, with vanillic acid and syringic acid as markers. The other noteworthy fingerprints enabled by online measurements included linoleic acid, cholesterol, and oleic acid for cooking, 2,5-dimethylfuran, stigmasterol, iso-/anteiso-alkanes, and fructose isomers for smoking, C₂₈ -C₃₄ even n-alkanes for candle burning, and monoterpenes for the use of air freshener, cleaning agents, and camphor oil. We showed clear evidence of chemical aging of cooking emissions, giving a hint of indoor heterogeneous chemistry. This study highlights the value of organic molecules measured at high time resolutions in enhancing our knowledge on indoor air quality.

Indoor air quality of 5,000 households and its determinants. Part B: Volatile organic compounds and inorganic gaseous pollutants in the Japan Environment and Children's study

Volatile organic compounds (VOCs) are major indoor air pollutants. Quantification of indoor concentrations of VOCs and identification of factors associated with these concentrations can help manage indoor air quality. This study measured the concentrations of VOCs and inorganic gaseous pollutants in around 5000 households in Japan and utilised a random forest model to estimate these concentrations and identify important determinants. The homes of 5017 randomly selected participants in the Japan Environment and Children's Study (JECS) were visited twice, when the children were aged 1.5 and 3 years. Twelve VOCs and inorganic gaseous pollutants were measured during 7 days by passive samplers. Various factors in these households, including household appliances, building characteristics, cooking styles, use of consumer products, renovation, pets, personal behaviours and ventilation were recorded. A random forest model with recursive feature elimination was utilised to identify factors predictive of VOCs and inorganic gaseous pollutants. Toluene, formaldehyde and acetaldehyde were the dominant indoor VOCs. The 95th percentiles of indoor p-dichlorobenzene concentrations at 1.5 and 3 years were 67 μg/m³ and 71 μg/m³, respectively. Random forest models with coefficients of determination ranging from 0.34 to 0.76 outperformed the traditional linear regression models. Factors associated with indoor VOC and inorganic gaseous pollutant concentrations included their outdoor concentrations, indoor and outdoor temperature and relative humidity, month of the year, hours windows were open, kerosene heater use and times of operation and building age. The results provided basic descriptions of indoor VOCs and inorganic gaseous pollutants in Japan and identified several determinants of these concentrations. These determinants should be considered to maintain indoor air quality. These results can be used in epidemiological assessments of the effects of VOCs and inorganic gaseous pollutants on health in children.

Volatile Organic Compounds in Underground Shopping Districts in Korea

Underground shopping districts (USDs) are susceptible to severe indoor air pollution, which can adversely impact human health. We measured 24 volatile organic compounds (VOCs) in 13 USDs throughout South Korea from July to October 2017, and the human risk of inhaling hazardous substances was evaluated. The sum of the concentrations of the 24 VOCs was much higher inside the USDs than in the open air. Based on factor analysis, six indoor air pollution sources were identified. Despite the expectation of a partial outdoor effect, the impacts of the indoor emissions were significant, resulting in an indoor/outdoor (I/O) ratio of 5.9 and indicating elevated indoor air pollution. However, the effects of indoor emissions decreased, and the contributions of the pollution sources reduced when the USD entrances were open and the stores were closed. Although benzene, formaldehyde, and acetaldehyde exhibited lower concentrations compared to previous studies, they still posed health risks in both indoor and outdoor settings. Particularly, while the indoor excess cancer risk (ECR) of formaldehyde was ~10 times higher than its outdoor ECR, benzene had a low I/O ratio (1.1) and a similar ECR value. Therefore, indoor VOC concentrations could be reduced by managing inputs of open air into USDs.

Firefighter exposures to organic and inorganic gas emissions in emergency residential and industrial fires

The gas emissions generated from fires could cause mortalities and diseases in firefighters. Gas emissions from fire contain a mixture of a wide range of organic and inorganic gases, depending on several elements that are not currently known. In this study, firefighters were equipped with portable gas detectors to measure selected organic and inorganic gases in 26 emergency fire incidents. The fire incidents were categorized as industrial or residential based on their source. The exposure of firefighters to volatile organic compounds (VOCs) in residential fires was double that in industrial fires. This is probably due to the contents of the houses, as more VOCs are released from textiles and furniture. The concentration of toluene, which is widely used in cosmetics and paints in housing, was fifteen-fold higher in residential fires than industrial fires. The exposure of firefighters to inorganic gases was much higher in industrial fires than residential fires. The concentration of hydrogen chloride, which is generated from the combustion of chlorinated plastics, such as industrial pipes and cables, in industrial fires was 18-fold higher than that in residential fires. Additionally, in this study, we found that the concentration of VOCs that poses cancer and non-cancer health risk to firefighters increases in residential fire incidents to almost three times that in industrial fire incidents. Hydrogen sulfide and sulfur dioxide concentrations were higher in industrial fire incidents than in residential fire incidents. The level of hydrogen sulfide and sulfur dioxide were 19-fold and 8-fold higher, respectively, in industrial fire incidents than in residential fire incidents. This study reveals that gas emissions vary widely between industrial and residential fires.

Head, Shoulders, Knees, and Toes: Placement of Wearable Passive Samplers Alters Exposure Profiles Observed

Chemical exposures are a major risk factor for many diseases. Comprehensive characterization of personal exposures is necessary to highlight chemicals of concern and factors that influence these chemical exposure dynamics. For this purpose, wearable passive samplers can be applied to assess longitudinal personal exposures to airborne contaminants. Questions remain regarding the impact of sampler placement at different locations of the body on the exposure profiles observed and how these placements affect the monitoring of seasonal dynamics in exposures. This study assessed personal air contaminant exposure using passive samplers worn in parallel across 32 participant's wrists, chest, and shoes over 24 h. Samplers were analyzed by thermal desorption gas chromatography high-resolution mass spectrometry. Personal exposure profiles were similar for about one-third of the 275 identified chemicals, irrespective of sampler placement. Signals of certain semivolatile organic compounds (SVOCs) were enhanced in shoes and, to a lesser extent, wrist samplers, as compared to those in chest samplers. Signals of volatile organic compounds were less impacted by sampler placement. Results showed that chest samplers predominantly captured more volatile exposures, as compared to those of particle-bound exposures, which may indicate predominant monitoring of chemicals via the inhalation route of exposure for chest samplers. In contrast, shoe samplers were more sensitive to particle-bound SVOCs. Seventy-one chemicals changed across participants between winter and summer in the same manner for two or more different sampler placements on the body, whereas 122 chemicals were observed to have seasonal differences in only one placement. Hence, the placement in certain cases significantly impacts exposure dynamics observed. This work shows that it is essential in epidemiological studies undertaking exposure assessment to consider the consequence of the placement of exposure monitors.

A prospective study on the role of smoking, environmental tobacco smoke, indoor painting and living in old or new buildings on asthma, rhinitis and respiratory symptoms

We studied associations between tobacco smoke, home environment and respiratory health in a 10 year follow up of a cohort of 11,506 adults in Northern Europe. Multilevel logistic regression models were applied to estimate onset and remission of symptoms. Current smokers at baseline developed more respiratory symptoms (OR = 1.39-4.43) and rhinitis symptoms (OR = 1.35). Starting smoking during follow up increased the risk of new respiratory symptoms (OR = 1.54-1.97) and quitting smoking decreased the risk (OR = 0.34-0.60). ETS at baseline increased the risk of wheeze (OR = 1.26). Combined ETS at baseline or follow up increased the risk of wheeze (OR = 1.27) and nocturnal cough (OR = 1.22). Wood painting at baseline reduced remission of asthma (OR 95%CI: 0.61, 0.38-0.99). Floor painting at home increased productive cough (OR 95%CI: 1.64, 1.15-2.34) and decreased remission of wheeze (OR 95%CI: 0.63, 0.40-0.996). Indoor painting (OR 95%CI: 1.43, 1.16-1.75) and floor painting (OR 95%CI: 1.77, 1.11-2.82) increased remission of allergic rhinitis. Living in the oldest buildings (constructed before 1960) was associated with higher onset of nocturnal cough and doctor diagnosed asthma. Living in the newest buildings (constructed 1986-2001) was associated with higher onset of nocturnal breathlessness (OR = 1.39) and rhinitis (OR = 1.34). In conclusion, smoking, ETS and painting indoor can be risk factors for respiratory symptoms. Wood painting and floor painting can reduce remission of respiratory symptoms. Smoking can increase rhinitis. Living in older buildings can be a risk factor for nocturnal cough and doctor diagnosed asthma. Living in new buildings can increase nocturnal dyspnoea and rhinitis.

Indoor Exposure to Selected Air Pollutants in the Home Environment: A Systematic Review

(1) Background: There is increasing awareness that the quality of the indoor environment affects our health and well-being. Indoor air quality (IAQ) in particular has an impact on multiple health outcomes, including respiratory and cardiovascular illness, allergic symptoms, cancers, and premature mortality. (2) Methods: We carried out a global systematic literature review on indoor exposure to selected air pollutants associated with adverse health effects, and related household characteristics, seasonal influences and occupancy patterns. We screened records from six bibliographic databases: ABI/INFORM, Environment Abstracts, Pollution Abstracts, PubMed, ProQuest Biological and Health Professional, and Scopus. (3) Results: Information on indoor exposure levels and determinants, emission sources, and associated health effects was extracted from 141 studies from 29 countries. The most-studied pollutants were particulate matter (PM_2.5 and PM₁₀); nitrogen dioxide (NO₂); volatile organic compounds (VOCs) including benzene, toluene, xylenes and formaldehyde; and polycyclic aromatic hydrocarbons (PAHs) including naphthalene. Identified indoor PM_2.5 sources include smoking, cooking, heating, use of incense, candles, and insecticides, while cleaning, housework, presence of pets and movement of people were the main sources of coarse particles. Outdoor air is a major PM_2.5 source in rooms with natural ventilation in roadside households. Major sources of NO₂ indoors are unvented gas heaters and cookers. Predictors of indoor NO₂ are ventilation, season, and outdoor NO₂ levels. VOCs are emitted from a wide range of indoor and outdoor sources, including smoking, solvent use, renovations, and household products. Formaldehyde levels are higher in newer houses and in the presence of new furniture, while PAH levels are higher in smoking households. High indoor particulate matter, NO₂ and VOC levels were typically associated with respiratory symptoms, particularly asthma symptoms in children. (4) Conclusions: Household characteristics and occupant activities play a large role in indoor exposure, particularly cigarette smoking for PM_2.5, gas appliances for NO₂, and household products for VOCs and PAHs. Home location near high-traffic-density roads, redecoration, and small house size contribute to high indoor air pollution. In most studies, air exchange rates are negatively associated with indoor air pollution. These findings can inform interventions aiming to improve IAQ in residential properties in a variety of settings.

Volatile organic compounds in 169 energy-efficient dwellings in Switzerland

Exposure to elevated levels of certain volatile organic compounds (VOCs) in households has been linked to deleterious health effects. This study presents the first large-scale investigation of VOC levels in 169 energy-efficient dwellings in Switzerland. Through a combination of physical measurements and questionnaire surveys, we investigated the influence of diverse building characteristics on indoor VOCs. Among 74 detected compounds, carbonyls, alkanes, and alkenes were the most abundant. Median concentration levels of formaldehyde (14 μg/m³ ), TVOC (212 μg/m³ ), benzene (<0.1 μg/m³ ), and toluene (22 μg/m³ ) were below the upper exposure limits. Nonetheless, 90% and 50% of dwellings exceeded the chronic exposure limits for formaldehyde (9 μg/m³ ) and TVOC (200 μg/m³ ), respectively. There was a strong positive correlation among VOCs that likely originated from common sources. Dwellings built between 1950s and 1990s, and especially, those with attached garages had higher TVOC concentrations. Interior thermal retrofit of dwellings and absence of mechanical ventilation system were associated with elevated levels of formaldehyde, aromatics, and alkanes. Overall, energy-renovated homes had higher levels of certain VOCs compared with newly built homes. The results suggest that energy efficiency measures in dwellings should be accompanied by actions to mitigate VOC exposures as to avoid adverse health outcomes.

The Effects of Air Pollution on the Development of Atopic Disease

Air pollution is defined as the presence of noxious substances in the air at levels that impose a health hazard. Thus, there has been long-standing interest in the possible role of indoor and outdoor air pollutants on the development of respiratory disease. In this regard, asthma has been of particular interest but many studies have also been conducted to explore the relationship between air pollution, allergic rhinitis, and atopic dermatitis. Traffic-related air pollutants or TRAP refers to a broad group of pollutants including elemental carbon, black soot, nitrogen dioxide (NO₂₎, nitric oxide (NO), sulfur dioxide (SO₂₎, particulate matter (PM_2.5 and PM₁₀), carbon monoxide (CO), and carbon dioxide (CO₂). In this review, we aim to examine the current literature regarding the impact of early childhood exposure to TRAP on the development of asthma, allergic rhinitis, and atopic dermatitis. Although there is growing evidence suggesting significant associations, definitive conclusions cannot be made with regard to the effect of TRAP on these diseases. This conundrum may be due to a variety of factors, including different definitions used to define TRAP, case definitions under consideration, a limited number of studies, variation in study designs, and disparities between studies in consideration of confounding factors. Regardless, this review highlights the need for future studies to be conducted, particularly with birth cohorts that explore this relationship further. Such studies may assist in understanding more clearly the pathogenesis of these diseases, as well as other methods by which these diseases could be treated.

Evaluation and characterization of volatile air toxics indoors in a heavy polluted city of northwestern China in wintertime

Hazardous volatile organic compounds (VOCs) and carbonyls were evaluated in typical dwellings in Xi'an in northwestern China in wintertime. High indoor concentrations were observed for formaldehyde, acetone, naphthalene, methylene chloride and acetaldehyde, associated with characteristic pollution sources. In comparison, many of the target VOCs were higher in Chinese dwellings than those in other countries, suggesting the significances of indoor pollutions in China. Source apportionment with receptor model shows that furniture and building materials (44.5%), paints and adhesives (11.9%), household products (17.3%), smoking (14.5%), and cooking (9.8%) are the major contributors to the indoor VOCs and carbonyls. The health risk assessment shows that the cancer risks for formaldehyde (5.73 × 10^-5), 1,3-butadiene (2.07 × 10^-5) and 1,2-dichloroethane (1.44 × 10^-5) were much higher than the acceptable level of 1 × 10^-6 recommended by International Register for Certified Auditors (IRCA). The hazard quotient (HQ) of target VOCs were far less than the threshold (HQ = 1). Moreover, the practical efficiency of household air purifier in removal of the VOCs and carbonyls was examined first time in dwellings in northern China. The results prove that most of the indoor organic pollutants and their cancer risk to humans can be efficiently reduced, particularly for formaldehyde and 1,3-butadiene. The findings of the study offer useful preliminary and updated information on current indoor air toxics levels, dominant pollution sources and their potential health risks to residents in northwest China.

Home environment and diseases in early life are associated with allergic rhinitis

OBJECTIVE

Risk factors in relation to allergic rhinitis (AR) remain unclear despite considerable interest. This study aimed to analysis the relationship between home environment and diseases in early life and AR.

METHODS

In a case-control survey, 242 AR patients and 258 healthy persons responded to questionnaires designed to capture pre-pregnancy/pregnancy diseases, maternal medication usage, diseases in early life of participants, family allergic history and home environmental factors. Forty risk factors potentially connected with AR were investigated and analyzed with chi-square test and logistic regression.

RESULTS

There was no correlation between mother's disorders such as periodontitis, chronic rhinitis, diabetes etc. and AR (p > 0.05). A logistic regression analysis showed that neonatal jaundice (p < 0.001), respiratory system infection (p < 0.001), diarrhea (p < 0.01), eczema (p < 0.01) in the early life and home environmental factors such as house decoration (p < 0.01), mold environment (p < 0.001), keeping flowers and plants (p < 0.001), passive smoking (p < 0.01) were associated with AR.

CONCLUSION

Diseases in early life and home environment are closely associated with AR.

Indoor levels of volatile organic compounds and formaldehyde from emission sources at elderly care centers in Korea

The objective of this study is to characterize indoor and outdoor levels of volatile organic compounds (VOCs) and formaldehyde (HCHO) and identify indoor emission sources in thirty elderly care centers (ECCs) located in the Seoul metropolitan city and Gyeonggi province in Korea. Air monitoring samples from indoor and outdoor environments were collected from January to December in 2007. Statistical analyses of indoor and outdoor VOCs and HCHO levels in three rooms (a bedroom, living, and dining rooms) of each ECC were performed, and these were compared to identify environmental factors associated with an increase of indoor pollution levels. Total volatile organic compounds (TVOC) levels were significantly (p<0.05) different between indoor (230.7±1.7 μg/m3) and outdoor (137.8±1.9 μg/m3) environments, with an I/O ratio of 1.67. The indoor HCHO level (20.1±1.6 μg/m3) was significantly (p<0.05) higher than the outdoor level (8.1±1.9 μg/m3), with an I/O ratio of 2.48. Indoor VOCs and HCHO levels in the bedrooms were significantly (p<0.05) higher than those in the living and dining rooms. Furthermore, indoor levels of VOCs and HCHO at ECCs were significantly (p<0.05) different depending on environmental factors such as the use of carpet, paint, and wooden furniture. In multiple regression analysis, indoor VOCs and HCHO levels at ECCs were significantly (p<0.05) correlated with two micro-environmental factors: the use of carpet and paint. This study confirmed that indoor VOCs and HCHO levels were significantly higher than those in outdoor environments. These air pollutants were mainly emitted from indoor sources, such as carpet, paint, and construction materials at the ECCs in Korea.

Factors Effecting the Total Volatile Organic Compound (TVOC) Concentrations in Slovak Households

Thirty five Slovak households were selected for an investigation of indoor environmental quality. Measuring of indoor air physical and chemical factors and a questionnaire survey was performed during May 2017. The range of permissible operative temperature was not met in 11% of objects. Relative humidity met the legislative requirements in all monitored homes. Concentrations of total volatile organic compounds (TVOCs) were significantly higher in the apartments than in the family houses. The average TVOC levels in the apartments and family houses were 519.7 µg/m³ and 330.2 µg/m³, respectively. Statistical analysis confirmed the effect of indoor air temperature, relative humidity and particulate matter (PM_0.5 and PM₁) on the levels of TVOCs. Higher TVOC levels were observed also in homes where it is not a common practice to open windows during cleaning activities. Other factors that had a statistically significant effect on concentrations of volatile organic compounds were heating type, attached garage, location of the apartment within residential building (the floor), as well as number of occupants. Higher TVOC concentrations were observed in indoor than outdoor environment, while further analysis showed the significant impact of indoor emission sources on the level of these compounds in buildings. The questionnaire study showed a discrepancy between objective measurement and subjective assessment in the household environment, and pointed to insufficient public awareness about volatile organic compounds (VOCs).

Microbes and associated soluble and volatile chemicals on periodically wet household surfaces

BACKGROUND

Microorganisms influence the chemical milieu of their environment, and chemical metabolites can affect ecological processes. In built environments, where people spend the majority of their time, very little is known about how surface-borne microorganisms influence the chemistry of the indoor spaces. Here, we applied multidisciplinary approaches to investigate aspects of chemical microbiology in a house.

METHODS

We characterized the microbial and chemical composition of two common and frequently wet surfaces in a residential setting: kitchen sink and bathroom shower. Microbial communities were studied using culture-dependent and independent techniques, including targeting RNA for amplicon sequencing. Volatile and soluble chemicals from paired samples were analyzed using state-of-the-art techniques to explore the links between the observed microbiota and chemical exudates.

RESULTS

Microbial analysis revealed a rich biological presence on the surfaces exposed in kitchen sinks and bathroom shower stalls. Microbial composition, matched for DNA and RNA targets, varied by surface type and sampling period. Bacteria were found to have an average of 25× more gene copies than fungi. Biomass estimates based on qPCR were well correlated with measured total volatile organic compound (VOC) emissions. Abundant VOCs included products associated with fatty acid production. Molecular networking revealed a diversity of surface-borne compounds that likely originate from microbes and from household products.

CONCLUSIONS

Microbes played a role in structuring the chemical profiles on and emitted from kitchen sinks and shower stalls. Microbial VOCs (mVOCs) were predominately associated with the processing of fatty acids. The mVOC composition may be more stable than that of microbial communities, which can show temporal and spatial variation in their responses to changing environmental conditions. The mVOC output from microbial metabolism on kitchen sinks and bathroom showers should be apparent through careful measurement, even against a broader background of VOCs in homes, some of which may originate from microbes in other locations within the home. A deeper understanding of the chemical interactions between microbes on household surfaces will require experimentation under relevant environmental conditions, with a finer temporal resolution, to build on the observational study results presented here.

The effect of prenatal TVOC exposure on birth and infantile weight: the Mothers and Children's Environmental Health study

BACKGROUNDVolatile organic compounds (VOCs) might restrict prenatal and postnatal growth. However, the effect of the exposure of prenatal VOCs on postnatal growth has not been studied sufficiently. Thus, we investigated the relationship between the exposure of total volatile organic compounds (TVOCs) during pregnancy and its effects on postnatal growth.METHODSA total of 383 pregnant participants were enrolled from 2006 to 2008. We investigated maternal characteristics using a questionnaire. Personal air samples of TVOCs were obtained in mid or late pregnancy. After these mothers had given birth, 360 singleton newborns were selected and postnatal follow-up data were collected at 6, 12, 24, and 36 months, as well as anthropometric factors including body weight. Multiple general linear and mixed models were applied for statistical analyses.RESULTSThe mean concentration of prenatal exposure to TVOCs was 284.2 μg/m³ and that of formaldehyde was 81.6 μg/m³. The birth weight of newborns decreased significantly with prenatal TVOC exposure (β=-45.89, P=0.04). The adjusted mean body weight was 300 g lower in the high-TVOC group (⩾75th) compared with that in the low-exposure group (<75th).CONCLUSIONThese results indicate that elevated exposure to TVOCs during the prenatal period may adversely influence early postnatal growth.

Infants' indoor and outdoor residential exposure to benzene and respiratory health in a Spanish cohort

Benzene exposure represents a potential risk for children's health. Apart from being a known carcinogen for humans (group 1 according to IARC), there is scientific evidence suggesting a relationship between benzene exposure and respiratory problems in children. But results are still inconclusive and inconsistent. This study aims to assess the determinants of exposure to indoor and outdoor residential benzene levels and its relationship with respiratory health in infants. Participants were 1-year-old infants (N = 352) from the INMA cohort from Valencia (Spain). Residential benzene exposure levels were measured inside and outside dwellings by means of passive samplers in a 15-day campaign. Persistent cough, low respiratory tract infections and wheezing during the first year of life, and covariates (dwelling traits, lifestyle factors and sociodemographic data) were obtained from parental questionnaires. Multiple Tobit regression and logistic regression models were performed to assess factors associated to residential exposure levels and health associations, respectively. Indoor levels were higher than outdoor ones (1.46 and 0.77 μg/m³, respectively; p < 0.01). A considerable percentage of dwellings, 42% and 21% indoors and outdoors respectively, surpassed the WHO guideline of 1.7 μg/m³ derived from a lifetime risk of leukemia above 1/100 000. Monitoring season, maternal country of birth and parental tobacco consumption were associated with residential benzene exposure (indoor and outdoors). Additionally, indoor levels were associated with mother's age and type of heating, and outdoor levels were linked with zone of residence and distance from industrial areas. After adjustment for confounding factors, no significant associations were found between residential benzene exposure levels and respiratory health in infants. Hence, our study did not support the hypothesis for the benzene exposure effect on respiratory health in children. Even so, it highlights a public health concern related to the personal exposure levels, since a considerable number of children surpassed the abovementioned WHO guideline for benzene exposure.

Removal of Indoor Volatile Organic Compounds via Photocatalytic Oxidation: A Short Review and Prospect

Volatile organic compounds (VOCs) are ubiquitous in indoor environments. Inhalation of VOCs can cause irritation, difficulty breathing, and nausea, and damage the central nervous system as well as other organs. Formaldehyde is a particularly important VOC as it is even a carcinogen. Removal of VOCs is thus critical to control indoor air quality (IAQ). Photocatalytic oxidation has demonstrated feasibility to remove toxic VOCs and formaldehyde from indoor environments. The technique is highly-chemical stable, inexpensive, non-toxic, and capable of removing a wide variety of organics under light irradiation. In this paper, we review and summarize the traditional air cleaning methods and current photocatalytic oxidation approaches in both of VOCs and formaldehyde degradation in indoor environments. Influencing factors such as temperature, relative humidity, deactivation and reactivations of the photocatalyst are discussed. Aspects of the application of the photocatalytic technique to improve the IAQ are suggested.

An assessment of air quality reflecting the chemosensory irritation impact of mixtures of volatile organic compounds

We present a method to assess the air quality of an environment based on the chemosensory irritation impact of mixtures of volatile organic compounds (VOCs) present in such environment. We begin by approximating the sigmoid function that characterizes psychometric plots of probability of irritation detection (Q) versus VOC vapor concentration to a linear function. First, we apply an established equation that correlates and predicts human sensory irritation thresholds (SIT) (i.e., nasal and eye irritation) based on the transfer of the VOC from the gas phase to biophases, e.g., nasal mucus and tear film. Second, we expand the equation to include other biological data (e.g., odor detection thresholds) and to include further VOCs that act mainly by "specific" effects rather than by transfer (i.e., "physical") effects as defined in the article. Then we show that, for 72 VOCs in common, Q values based on our calculated SITs are consistent with the Threshold Limit Values (TLVs) listed for those same VOCs on the basis of sensory irritation by the American Conference of Governmental Industrial Hygienists (ACGIH). Third, we set two equations to calculate the probability (Qmix) that a given air sample containing a number of VOCs could elicit chemosensory irritation: one equation based on response addition (Qmix scale: 0.00 to 1.00) and the other based on dose addition (1000*Qmix scale: 0 to 2000). We further validate the applicability of our air quality assessment method by showing that both Qmix scales provide values consistent with the expected sensory irritation burden from VOC mixtures present in a wide variety of indoor and outdoor environments as reported on field studies in the literature. These scales take into account both the concentration of VOCs at a particular site and the propensity of the VOCs to evoke sensory irritation.

Compilation and analysis of types and concentrations of airborne chemicals measured in various indoor and outdoor human environments

The main purpose of this article is to summarize and illustrate the results of a literature search on the types, levels, relative concentrations, concentration spread of individual chemicals, and number of airborne compounds (mostly volatile organic compounds, VOCs) that have been found, measured, and reported both indoors and outdoors. Two broad categories of indoor environments are considered: (1) home/school, and (2) commercial spaces. Also, two categories of outdoor environments are considered: (1) non-industrial and (2) industrial (the latter represented by the vicinity of a pig farm and the vicinity of an oil refinery). The outcome is presented as a series of graphs and tables containing the following statistics: geometric mean, arithmetic mean, median, standard deviation, variance, standard error, interquartile distance, minimum value, maximum value, and number of data (data count) for the air concentration of each reported compound in a given environment. A Supplementary Table allows interested readers to match each single value included in this compilation with its corresponding original reference.

Risk assessment of population inhalation exposure to volatile organic compounds and carbonyls in urban China

Over the past three decades, China has experienced rapid urbanization. The risks to its urban population posed by inhalation exposure to hazardous air pollutants (HAPs) have not been well characterized. Here, we summarize recent measurements of 16 highly prevalent HAPs in urban China and compile their distribution inputs. Based on activity patterns of urban Chinese working adults, we derive personal exposures. Using a probabilistic risk assessment method, we determine cancer and non-cancer risks for working females and males. We also assess the uncertainty associated with risk estimates using Monte Carlo simulation, accounting for variations in HAP concentrations, cancer potency factors (CPFs) and inhalation rates. Average total lifetime cancer risks attributable to HAPs are 2.27×10(-4) (2.27 additional cases per 10,000 people exposed) and 2.93×10(-4) for Chinese urban working females and males, respectively. Formaldehyde, 1,4-dichlorobenzene, benzene and 1,3-butadiene are the major risk contributors yielding the highest median cancer risk estimates, >1×10(-5). About 70% of the risk is due to exposures occurring in homes. Outdoor sources contribute most to the risk of benzene, ethylbenzene and carbon tetrachloride, while indoor sources dominate for all other compounds. Chronic exposure limits are not exceeded for non-carcinogenic effects, except for formaldehyde. Risks are overestimated if variation is not accounted for. Sensitivity analyses demonstrate that the major contributors to total variance are range of inhalation rates, CPFs of formaldehyde, 1,4-dichlorobenzene, benzene and 1,3-butadiene, and indoor home concentrations of formaldehyde and benzene. Despite uncertainty, risks exceeding the acceptable benchmark of 1×10(-6) suggest actions to reduce exposures. Future efforts should be directed toward large-scale measurements of air pollutant concentrations, refinement of CPFs and investigation of population exposure parameters. The present study is a first effort to estimate carcinogenic and non-carcinogenic risks of inhalation exposure to HAPs for the large working populations of Chinese cites.

Particulate matter in the indoor and outdoor air of a gymnasium and a fronton

An indoor/outdoor monitoring programme of PM10 was carried out in two sports venues (a fronton and a gymnasium). Levels always below 50 μg m(-3) were obtained in the fronton and outdoor air. Due to the climbing chalk and the constant process of resuspension, concentrations above 150 μg m(-3) were registered in the gymnasium. The chalk dust contributed to CO3 (2-) concentrations of 32 ± 9.4 μg m(-3) in this sports facility, which represented, on average, 18 % of the PM10 mass. Here, the carbonate levels were 128 times higher than those registered outdoors. Much lower concentrations, around 1 μg m(-3), were measured in the fronton. The chalk dust is also responsible for the high Mg(2+) concentrations in the gym (4.7 ± 0.89 μg m(-3)), unfolding a PM10 mass fraction of 2.7 %. Total carbon accounted for almost 30 % of PM10 in both indoor spaces. Aerosol size distributions were bimodal and revealed a clear dependence on physical activities and characteristics of the sports facilities. The use of climbing chalk in the gymnasium contributed significantly to the coarse mode. The average geometric mean diameter, geometric standard deviation and total number of coarse particles were 0.77 μm, 2.79 cm(-3) and 28 cm(-3), respectively.

Asthma and asthma related symptoms in 23,326 Chinese children in relation to indoor and outdoor environmental factors: the Seven Northeastern Cities (SNEC) Study

BACKGROUND

Both the levels and patterns of outdoor and indoor air pollutants have changed dramatically during the last decade in China. However, few studies have evaluated the effects of the present air pollution on the health of Chinese children. This study examines the association between outdoor and indoor air pollution and respiratory diseases among children living in Liaoning, a heavy industrial province of China.

METHODS

A cross-sectional study of 23,326 Chinese children aged 6 to 13 years was conducted in 25 districts of 7 cities in Northeast China during 2009. Three-year (2006-2008) average concentrations of particles with an aerodynamic diameter of ≤10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were calculated from monitoring stations in each of the 25 districts. We used two-level logistic regression models to examine the effects of yearly variations in exposure to each pollutant, controlling for important covariates.

RESULTS

The prevalence of respiratory symptoms was higher for those dwelling close to a busy road, those living near smokestacks or factories, those living with smokers, those living in one-story houses typically with small yards, and those with home renovation, bedroom carpet or pets. Ventilation device use was associated with decreased odds of asthma in children. The adjusted odds ratio for diagnosed-asthma was 1.34 (95% confidence interval [CI], 1.24-1.45) per 31 μg/m(3) increase in PM10, 1.23 (95%CI, 1.14-1.32) per 21 μg/m(3) increase in SO2, 1.25 (95%CI, 1.16-1.36) per 10 μg/m(3) increase in NO2, and 1.31 (95%CI, 1.21-1.41) per 23 μg/m(3) increase in O3, respectively.

CONCLUSION

Outdoor and indoor air pollution was associated with an increased likelihood of respiratory morbidity among Chinese children.

Home renovation, family history of atopy, and respiratory symptoms and asthma among children living in China

OBJECTIVES

To investigate the association of indoor air pollution with the respiratory health of children, we evaluated the associations of children's respiratory symptoms with asthma and recent home renovation.

METHODS

We conducted a cross-sectional survey in a school recruitment sample of 31,049 children aged 2 to 14 years in 25 districts of 7 cities of northeast China in 2008-2009. The children's parents completed standardized questionnaires characterizing the children's histories of respiratory symptoms and illness, recent home renovation information, and other associated risk factors.

RESULTS

The effects of home renovation in the past 2 years were significantly associated with cough, phlegm, current wheeze, doctor-diagnosed asthma, and current asthma. The associations we computed when combining the status of home renovation and family history of atopy were higher than were those predicted from the combination of the separate effects. However, the interactions between home renovation and family history of atopy on a multiplicative scale were not statistically significant (P>.05).

CONCLUSIONS

Home renovation is associated with increases in the prevalence of respiratory symptoms and asthma in children. The effects of different renovation materials on child respiratory health should be studied further.

Quantitative assessments of indoor air pollution and the risk of childhood acute leukemia in Shanghai

We investigated the association between indoor air pollutants and childhood acute leukemia (AL). A total of 105 newly diagnosed cases and 105 1:1 gender-, age-, and hospital-matched controls were included. Measurements of indoor pollutants (including nitrogen dioxide (NO2) and 17 types of volatile organic compounds (VOCs)) were taken with diffusive samplers for 64 pairs of cases and controls. Higher concentrations of NO2 and almost half of VOCs were observed in the cases than in the controls and were associated with the increased risk of childhood AL. The use of synthetic materials for wall decoration and furniture in bedroom was related to the risk of childhood AL. Renovating the house in the last 5 years, changing furniture in the last 5 years, closing the doors and windows overnight in the winter and/or summer, paternal smoking history and outdoor pollutants affected VOC concentrations. Our results support the association between childhood AL and indoor air pollution.

Asthma and allergic diseases in preschool children in Korea: findings from the pilot study of the Korean Surveillance System for Childhood Asthma

OBJECTIVE

This article was intended to introduce the Korean Surveillance System for Childhood Asthma (KSSCA) and also to determine the factors that increase the risk for the development of asthma and allergic diseases in preschool children in Korea based on the study results.

METHODS

The KSSCA pilot study was a web-based, cross-sectional survey that sampled 1002 parents with a biological child aged 2-6 years that visited the website and participated in the survey. This website consisted of a questionnaire designed to measure the history and prevalence of asthma and allergic diseases, the characteristics of dwelling, lifestyle, and the socioeconomic status of the subjects. Using logistic regression analysis, odds ratios (ORs) and 95% confidence intervals (CIs) between each risk factor and disease development were calculated.

RESULTS

The rate of a family where a child had asthma was 7.4%, while 34.7% and 35.9% for allergic rhinitis and atopic dermatitis, respectively. The OR (95% CI) that a child whose parents had an allergic disease and was also diagnosed with an allergic disease was 2.86 (2.20-3.72). Children who lived in the first floor or basement of apartments had a higher risk of atopic dermatitis, as well as children from socioeconomically vulnerable families. Upon analysis of allergic reaction tests and disease development, it was found that asthma was associated with the positive reaction of cockroaches and food, allergic rhinitis with mites, and atopic dermatitis with mold and food.

CONCLUSION

The study indicated that genetic and some environmental or socioeconomic factors might be important in the development of asthma and allergic diseases among preschool children in Korea through the web-survey.

Formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes in Louisiana and Mississippi

In 2006, area physicians reported increases in upper respiratory symptoms in patients living in U.S. Federal Emergency Management Agency (FEMA)-supplied trailers following Hurricanes Katrina and Rita. One potential etiology to explain their symptoms included formaldehyde; however, formaldehyde levels in these occupied trailers were unknown. The objectives of our study were to identify formaldehyde levels in occupied trailers and to determine factors or characteristics of occupied trailers that could affect formaldehyde levels. A disproportionate random sample of 519 FEMA-supplied trailers was identified in Louisiana and Mississippi in November 2007. We collected and tested an air sample from each trailer for formaldehyde levels and administered a survey. Formaldehyde levels among all trailers in this study ranged from 3 parts per billion (ppb) to 590 ppb, with a geometric mean (GM) of 77 ppb [95% confidence interval (CI): 70-85; range: 3-590 ppb]. There were statistically significant differences in formaldehyde levels between trailer types (P < 0.01). The GM formaldehyde level was 81 ppb (95% CI: 72-92) among travel trailers (N = 360), 57 ppb (95% CI: 49-65) among mobile homes (N = 57), and 44 ppb (95% CI: 38-53) among park models (N = 44). Among travel trailers, formaldehyde levels varied significantly by brand. While formaldehyde levels varied by trailer type, all types tested had some levels ≥ 100 ppb.

Airborne molds and bacteria, microbial volatile organic compounds (MVOC), plasticizers and formaldehyde in dwellings in three North European cities in relation to sick building syndrome (SBS)

There are few studies on associations between airborne microbial exposure, formaldehyde, plasticizers in dwellings and the symptoms compatible with the sick building syndrome (SBS). As a follow-up of the European Community Respiratory Health Survey (ECRHS II), indoor measurements were performed in homes in three North European cities. The aim was to examine whether volatile organic compounds of possible microbial origin (MVOCs), and airborne levels of bacteria, molds, formaldehyde, and two plasticizers in dwellings were associated with the prevalence of SBS, and to study associations between MVOCs and reports on dampness and mold. The study included homes from three centers included in ECRHS II. A total of 159 adults (57% females) participated (19% from Reykjavik, 40% from Uppsala, and 41% from Tartu). A random sample and additional homes with a history of dampness were included. Exposure measurements were performed in the 159 homes of the participants. MVOCs were analyzed by GCMS with selective ion monitoring (SIM). Symptoms were reported in a standardized questionnaire. Associations were analyzed by multiple logistic regression. In total 30.8% reported any SBS (20% mucosal, 10% general, and 8% dermal symptoms) and 41% of the homes had a history of dampness and molds There were positive associations between any SBS and levels of 2-pentanol (P=0.002), 2-hexanone (P=0.0002), 2-pentylfuran (P=0.009), 1-octen-3-ol (P=0.002), formaldehyde (P=0.05), and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Texanol) (P=0.05). 1-octen-3-ol (P=0.009) and 3-methylfuran (P=0.002) were associated with mucosal symptoms. In dwellings with dampness and molds, the levels of total bacteria (P=0.02), total mold (P=0.04), viable mold (P=0.02), 3-methylfuran (P=0.008) and ethyl-isobutyrate (P=0.02) were higher. In conclusion, some MVOCs like 1-octen-3-ol, formaldehyde and the plasticizer Texanol, may be a risk factor for sick building syndrome. Moreover, concentrations of airborne molds, bacteria and some other MVOCs were slightly higher in homes with reported dampness and mold.

Formaldehyde in the ambient atmosphere: from an indoor pollutant to an outdoor pollutant?

Formaldehyde has been discussed as a typical indoor pollutant for decades. Legal requirements and ever-lower limits for formaldehyde in indoor air have led to a continual reduction in the amount of formaldehyde released from furniture, building materials, and household products over many years. Slowly, and without much attention from research on indoor air, a change of paradigm is taking place, however. Today, the formaldehyde concentrations in outdoor air, particularly in polluted urban areas, sometimes already reach indoor levels. This is largely a result of photochemical processes and the use of biofuels. In the medium term, this development might have consequences for the way buildings are ventilated and lead to a change in the way we evaluate human exposure.

Selective permeation of moisture and VOCs through polymer membranes used in total heat exchangers for indoor air ventilation

Fresh air ventilation is central to indoor environmental control. Total heat exchangers can be key equipment for energy conservation in ventilation. Membranes have been used for total heat exchangers for more than a decade. Much effort has been spent to achieve water vapor permeability of various membranes; however, relatively little attention has been paid to the selectivity of moisture compared with volatile organic compounds (VOCs) through such membranes. In this investigation, the most commonly used membranes, both hydrophilic and hydrophobic ones, are tested for their permeability for moisture and five VOCs (acetic acid, formaldehyde, acetaldehyde, toluene, and ethane). The selectivity of moisture vs. VOCs in these membranes is then evaluated. With a solution-diffusion model, the solubility and diffusivity of moisture and VOCs in these membranes are calculated. The resulting data could provide some reference for future material selection.

PRACTICAL IMPLICATIONS

Total heat exchangers are important equipment for fresh air ventilation with energy conservation. However, their implications for indoor air quality in terms of volatile organic compound permeation have not been known. The data in this article help us to clarify the impacts on indoor VOC levels of membrane-based heat exchangers. Guidelines for material selection can be obtained for future use total heat exchangers for building ventilation.

Roles of pollution in the prevalence and exacerbations of allergic diseases in Asia

The prevalence of asthma and allergic diseases has been found to be increasingly rapidly, especially in developing countries. Environmental factors have been found to be important contributors to the manifestations of allergic diseases. Air pollution has been extensively studied in different regions of the world. The levels of ambient air pollutants in many Asian countries are very high when compared with those in developed Western countries. However, the prevalence of asthma was relatively low across many Asian countries. Many studies have clearly documented that environmental air pollution is an important factor resulting in exacerbations of asthma. In particular, levels of traffic-related pollutants are increasing rapidly across many Asian countries in parallel with the level of urbanization and economic development. The loss of protective factors associated with a rural environment will further contribute to the adverse effect on patients with allergic diseases such as asthma. In this review the roles of air pollution were examined in relation to the inception and exacerbations of allergic diseases in Asia.

Do indoor environments influence asthma and asthma-related symptoms among adults in homes?: a review of the literature

This review summarizes the results of epidemiological studies focusing on the detrimental effects of home environmental factors on asthma morbidity in adults. We reviewed the literature on indoor air quality (IAQ), physical and sociodemographic factors, and asthma morbidity in homes, and identified commonly reported asthma, allergic, and respiratory symptoms involving the home environment. Reported IAQ and asthma morbidity data strongly indicated positive associations between indoor air pollution and adverse health effects in most studies. Indoor factors most consistently associated with asthma and asthma-related symptoms in adults included fuel combustion, mold growth, and environmental tobacco smoke. Environmental exposure may increase an adult's risk of developing asthma and also may increase the risk of asthma exacerbations. Evaluation of present IAQ levels, exposure characteristics, and the role of exposure to these factors in relation to asthma morbidity is important for improving our understanding, identifying the burden, and for developing and implementing interventions aimed at reducing asthma morbidity.

Hazard assessment of chemical air contaminants measured in residences

Identifying air pollutants that pose a potential hazard indoors can facilitate exposure mitigation. In this study, we compiled summary results from 77 published studies reporting measurements of chemical pollutants in residences in the United States and in countries with similar lifestyles. These data were used to calculate representative mid-range and upper-bound concentrations relevant to chronic exposures for 267 pollutants and representative peak concentrations relevant to acute exposures for five activity-associated pollutants. Representative concentrations are compared to available chronic and acute health standards for 97 pollutants. Fifteen pollutants appear to exceed chronic health standards in a large fraction of homes. Nine other pollutants are identified as potential chronic health hazards in a substantial minority of homes, and an additional nine are identified as potential hazards in a very small percentage of homes. Nine pollutants are identified as priority hazards based on the robustness of measured concentration data and the fraction of residences that appear to be impacted: acetaldehyde; acrolein; benzene; 1,3-butadiene; 1,4-dichlorobenzene; formaldehyde; naphthalene; nitrogen dioxide; and PM(2.5). Activity-based emissions are shown to pose potential acute health hazards for PM(2.5), formaldehyde, CO, chloroform, and NO(2).

PRACTICAL IMPLICATIONS

This analysis identifies key chemical contaminants of concern in residential indoor air using a comprehensive and consistent hazard-evaluation protocol. The identification of a succinct group of chemical hazards in indoor air will allow for successful risk ranking and mitigation prioritization for the indoor residential environment. This work also indicates some common household activities that may lead to the acute levels of pollutant exposure and identifies hazardous chemicals for priority removal from consumer products and home furnishings.

Indoor air pollution and childhood asthma: variations between urban and rural areas

Health effects of indoor pollution have been investigated overall in urban areas. To compare the potential effect of home air pollutants on asthma in urban and rural houses, two case-control populations, composed of children living in the city (32 asthmatics and 31 controls) and in the countryside (24 asthmatics and 27 controls) were included. During 1 week, nitrogen dioxide, fine particles, and volatile organic compounds (formaldehyde, acetaldehyde, benzene, toluene, ethylbenzene, and xylenes) were assessed at home. Urban dwellings were found to be more polluted than rural ones, with concentrations up to two times higher. In the whole population, exposure to acetaldehyde and toluene was significantly associated with a higher risk of asthma. In the urban population, the association with toluene was significant in children studied during winter, and with toluene, xylenes, and ethylbenzene when cases were restricted to current asthmatics. In rural settings, a relationship between asthma and formaldehyde exposure was observed (OR = 10.7; 95% CI 1.69-67.61). Our findings suggest that daily continuous exposures to pollutants may be implicated in asthma, even in the case of low exposure, as those found in rural areas. Our results could also indicate a specific effect of indoor pollution in the rural environment.

PRACTICAL IMPLICATIONS

Everyday exposure to indoor pollution was associated with a higher risk of childhood asthma. These findings suggest that even at low concentrations, pollutants could be implicated in asthma and reinforce the importance of establishing guideline values to improve indoor air quality by limiting sources or by optimizing ventilation. Specific effects could occur in rural environments where pollution differs from urban area.