Migration of volatile organic compounds from attached garages to residences: a major exposure source

Vehicle garages often contain high concentrations of volatile organic compounds (VOCs) that may migrate into adjoining residences. This study characterizes VOC concentrations, exposures, airflows, and source apportionments in 15 single-family houses with attached garages in southeast Michigan. Fieldwork included inspections to determine possible VOC sources, deployment of perfluorocarbon tracer (PFT) sources in garages and occupied spaces, and measurements of PFT, VOC, and CO(2) concentrations over a 4-day period. Air exchange rates (AERs) averaged 0.43+/-0.37 h(-1) in the houses and 0.77+/-0.51 h(-1) in the garages, and air flows from garages to houses averaged 6.5+/-5.3% of the houses' overall air exchange. A total of 39 VOC species were detected indoors, 36 in the garage, and 20 in ambient air. Garages showed high levels of gasoline-related VOCs, e.g., benzene averaged 37+/-39 microg m(-3). Garage/indoor ratios and multizone IAQ models show that nearly all of the benzene and most of the fuel-related aromatics in the houses resulted from garage sources, confirming earlier reports that suggested the importance of attached garages. Moreover, doses of VOCs such as benzene experienced by non-smoking individuals living in houses with attached garages are dominated by emissions in garages, a result of exposures occurring in both garage and house microenvironments. All of this strongly suggests the need to better control VOC emissions in garages and contaminant migration through the garage-house interface.     

Volatile organic compounds: do they present a risk to our health?

Indoor air quality has been recognised as a significant health, environment, and economic issue in many countries. Research findings have demonstrated that some air pollutants occur more frequently and at a higher concentration in indoor air than in outdoor air, including volatile organic compounds (VOCs). In this context, the indoor environment can be of crucial importance because modem society spends most of their time indoors, and exposure to VOCs may result in a spectrum of illnesses ranging from mild, such as irritation, to very severe effects, including cancer. These effects have been seen at very low levels of exposure in many epidemiological studies. In this review, we discuss the nature of the VOCs that are ubiquitous in indoor environment and the evidence for adverse health effects associated with exposure to some of these compounds.     

The influence of personal activities on exposure to volatile organic compounds

Seven persons volunteered to perform 25 common activities thought to increase personal exposure to volatile organic chemicals (VOCs) during a 3-day monitoring period. Personal, indoor, and outdoor air samples were collected on Tenax cartridges three times per day (evening, overnight, and daytime) and analyzed by GC-MS for 17 target VOCs. Samples of exhaled breath were also collected before and after each monitoring period. About 20 activities resulted in increasing exposure to one or more of the target VOCs, often by factors of 10, sometimes by factors of 100, compared to exposures during the sleep period. These concentrations were far above the highest observed outdoor concentrations during the length of the study. Breath levels were often significantly correlated with previous personal exposures. Major exposures were associated with use of deodorizers (p-dichlorobenzene); washing clothes and dishes (chloroform); visiting a dry cleaners (1,1,1-trichloroethane, tetrachloroethylene); smoking (benzene, styrene); cleaning a car engine (xylenes, ethylbenzene, tetrachloroethylene); painting and using paint remover (n-decane, n-undecane); and working in a scientific laboratory (many VOCs). Continuously elevated indoor air levels of p-dichlorobenzene, trichloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, decane, and undecane were noted in several homes and attributed to unknown indoor sources. Measurements of exhaled breath suggested biological residence times in tissue of 12-18 hr and 20-30 hr for 1,1,1-trichloroethane and p-dichlorobenzene, respectively.     

Assessing exposure to air toxics relative to asthma

Asthma is a respiratory disease whose prevalence has been increasing since the mid 1970s and that affects more than 14.6 million residents of the United States. Environmental triggers of asthma include air pollutants that are respiratory irritants. Air toxics emitted into the ambient air are listed in the 1990 Clean Air Act Amendments as hazardous air pollutants (HAPs) if they can adversely affect human health, including the respiratory tract. HAPs include particulate and gaseous-phase pollutants, individual organic compounds and metals, and mixtures. Associations between asthma exacerbation and both particles and indoor volatile organic compounds (VOCs), often referred to as indoor air quality, have been reported. Studies conducted in the United States, Canada, and Europe over the past two decades have shown that most people living in the developed countries spend the majority of their time indoors and that the air concentrations of many air toxics or HAPs are higher indoors than in the ambient air in urban, suburban, and rural settings. Elevated indoor air concentrations result from emissions of air toxics from consumer products, household furnishings, and personal activities. The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to oversample homes in close proximity to ambient sources, excluding residences where smokers lived, to determine the contribution of ambient emissions to air toxics exposure. The ratios of indoor to outdoor air concentrations of some VOCs in homes measured during RIOPA were much greater than one, and for most other VOCs that had indoor-to-outdoor ratios close to unity in the majority of homes, elevated ratios were found in the paired samples with the highest concentration. Thus, although ambient emissions contribute to exposure of some air toxics indoors as well as outdoors, this was not true for all of the air toxics and especially for the higher end of exposures to most volatile organic air toxics examined. It is therefore critical, when evaluating potential effects of air toxics on asthma or other adverse health end points, to determine where the exposure occurs and the source contributions for each air toxic and target population separately and not to rely solely on ambient air concentration measurements.     

Exposure to air pollutants in English homes

BRE has conducted a national representative survey of air pollutants in 876 homes in England, designed to increase knowledge of baseline pollutant levels and factors associated with high concentrations. Homes were monitored for carbon monoxide (CO), nitrogen dioxide (NO(2)), formaldehyde and volatile organic compounds (VOCs). In the majority of the homes, concentrations of the measured pollutants were low. However, some homes have concentrations that would suggest a need for precautionary mitigation. Those factors that are most likely to lead to exposures of concern in homes are identified as gas cooking (for CO and NO(2)), the use of unflued appliances for heating (for CO and NO(2)), emissions from materials in new homes (for total VOC (TVOC) and formaldehyde), and painting and decorating, with a significant increase in risk suspected to exist where there is not a place to store materials away from the living space (for TVOC). It is noteworthy that seasonal effects on CO and NO(2) were largely due to indoor sources. This would need to be considered when interpreting time series studies of the effect of outdoor air pollution on health. It is also of some significance that the critical factors are related much more to sources than to ventilation: source control is therefore, as would be expected, the most appropriate approach to reducing the risk of hazardous exposure to air pollutants in homes.     

挥发性有机污染物在室内环境中的化学反应及其健康影响

室内环境中存在大量的挥发性有机污染物(VOCs),在O3和NO2存在的情况下,各污染物之间可能发生各种各样的化学反应,这些反应严重地影响了室内空气质量,造成室内人员的健康损害。该文论述了室内可能存在的主要化学反应,以及其带来的健康问题,并概括了相关研究的内容和存在的问题。对室内环境中VOCs的化学反应进行研究对于人体健康非常重要,有助于改进室内空气质量标准和建立建筑材料“生态标志”。     

Personal, indoor, and outdoor VOC exposures in a probability sample of children

As part of the Minnesota Children's Pesticide Exposure Study we measured volatile organic compound (VOC) concentrations in a probability sample of households with children. The 6-day average concentrations for 10 common VOCs were obtained in urban and nonurban residences twice during this multiphase study: screening-phase indoor measurements were collected in 284 households, and in the intensive-phase matched outdoor (O), indoor (I), and personal (P) measurements were collected in a subset (N=72) of the screened households. Screening-phase households with smokers had significantly higher concentrations of benzene and styrene compared to nonsmoking households; households with an attached garage had significantly higher levels of benzene, chloroform, styrene, and m/p- and o-xylene compared to households without an attached garage; and nonurban residences, which had a greater prevalence of smokers and attached garages, had significantly higher 1,1,1-trichloroethane, styrene, and toluene and significantly lower tetrachloroethylene concentrations compared to urban households. The screening-phase weighted distributions estimate the mean and variability in indoor VOC concentrations for more than 45,000 households with children in the census tracts sampled. Overall, median indoor concentrations of most VOCs measured in this study were similar to or lower than indoor levels measured previously in the United States. Intensive-phase outdoor VOC concentrations were generally lower than other major metropolitan areas, but urban concentrations were significantly higher than nonurban concentrations for all compounds except 1,1,1-trichloroethylene. A consistent pattern of P>I>O was observed for nine of 10 VOCs, with 1,1,1-trichloroethylene (I>P>O) being the only exception to this pattern. For most children, the indoor at-home microevironment was strongly associated with personal exposure after controlling for important covariates, but the ratio of median to upper bound exposures was smaller than that observed in studies of adults. There are relatively little data on VOC exposures in children, so these results are useful for estimating the central tendency and distribution of VOC exposures in locations where children spend a majority of their time.     

呼出气中挥发性有机污染物的采样和分析方法

提出了一种呼出气中挥发性有机污染物（ＶＯＣｓ）的采样和分析方法。用复合膜采气袋收集受试者重复呼出气样品，采用吸附浓缩／热解析／二次冷阱浓缩／再热解析进样，程序升温毛细管色谱柱和ＦＩＤ检测器分析。最低检出限苯为０．５ｎｇ／Ｌ三氯乙烯为５ｎｇ／Ｌ，整个采样与分析的相对标准偏差≤１５％，加标回收率平均为９３％。     

A participant-based approach to indoor/outdoor air monitoring in community health studies

Community health studies of traffic-related air pollution have been hampered by the cost and participant burden associated with collecting household-level exposure data. The current study utilized a participant-based approach to collect indoor and outdoor air monitoring data from 92 asthmatic and nonasthmatic children (9-13 years old) enrolled in two concurrent health studies in Detroit, Michigan (Mechanistic Indicators of Childhood Asthma and Detroit Children's Health Study) conducted by the US Environmental Protection Agency (EPA). Passive samplers were shipped to participating households and deployed by parents of study participants to collect indoor and outdoor measurements of nitrogen dioxide (NO(2)), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs) including naphthalene. Half of the households deployed VOC and NO(2) samplers for 7 days; the other half deployed PAH and NO(2) samplers for 2 days and additional PAH samplers for 1 day. Approximately 88% of the households that received air sampling kits completed the air monitoring. Compliance was significantly higher among participants asked to deploy all samplers for 7 days (85%) compared with participants asked to deploy some samplers for 2 days and others for 1 day (56%). The 7-day homes were also more likely to provide usable data (96%) compared with the 1- and 2-day homes (73%). Compliance and providing usable data did not vary between parents of asthmatic versus nonasthmatic study participants and were not reduced among households deploying duplicate samplers. These results suggest that participant-based sampling may be a feasible and cost-effective alternative to traditional exposure assessment approaches that can be applied in future epidemiological and community-based health studies.     

An evaluation of employee exposure to volatile organic compounds in three photocopy centers

Personal and area samples from three copy centres were collected in thermal desorption tubes and analyzed using gas chromatography-mass spectrometry. Real-time personal total volatile organic compounds (TVOC) were measured using a data-logging photoionization detector. Fifty-four different VOCs were detected in the area samples. The maximum concentration measured was 1132.0 ppb (toluene, copy center 3, day 1). Thirty-eight VOCs were detected in the personal samples and concentrations ranged from 0.1 ppb (1,1-biphenyl, p-dichlorobenzene, propylbenzene, styrene, and tetrachloroethylene) to 689.6 ppb (toluene). Real-time TVOC measurements indicated daily fluctuations in exposure, ranging from <71 to 21,300 ppb. The time-weighted average exposures for the photocopier operators on days 1 and 2 were 235 and 266 ppb and 6155 and 3683 ppb, in copy centers 2 and 3, respectively. Personal exposure measurements of individual VOCs were below accepted occupational standards and guidelines. For example, the maximum concentration was 0.3% of the permissible exposure limits (toluene, copy center 3). Exposures were highest in copy center 3; this is likely due to the presence of offset printing presses. It is concluded that photocopiers contribute a wide variety of VOCs to the indoor air of photocopy centers; however, exposures are at least 100 times below established standards.     

Vertical and horizontal variability of volatile organic compounds in homes in Eastern Germany.

A German study on Indoor Factors and Genetics in Asthma (INGA) will be conducted for 10 years in towns of Eastern and Western Germany. The study will include an indoor and outdoor exposure assessment of BTEX (BTEX=benzene, toluene, ethyl benzene, ortho-xylene, and meta- plus para-xylene) volatile organic compounds (VOCs). In a pilot study, which was conducted in Erfurt, a city in Eastern Germany, during the winter of 1994, vertical and horizontal variabilities of BTEX concentrations within the homes were examined in detail. Passive sampling was conducted in the living room (at 0.7, 1.2, and 2.0 m height), bedroom (2 m), kitchen (2 m), and outside the window of the living room, in 20 homes of randomly chosen adults. The 20 houses consisted often old concrete constructions ('Altneubauten'=OLD, constructed between 1960 and 1970) and ten new concrete constructions ('Neubauten'=NEW, constructed between 1970 and 1980). At each apartment, Organic Vapour Monitor (OVM) 3500 passive sampling devices (3M Company) were exposed for 7 days. After elution with carbon disulfide (CS2), the samples were analyzed with dual column gas chromatography (GC) with flame ionization detector (FID). No significant differences between the median values of the weekly average air concentrations of the BTEX VOCs in the different heights of measurement in the living rooms could be detected. Kitchen and living room median BTEX concentrations were equal and both significantly higher than the bedroom concentrations (except benzene). The indoor BTEX air concentrations were significantly higher than the outdoor concentrations (except benzene). Significant differences in BTEX indoor concentrations between OLD and NEW buildings could not be detected (except toluene).     

Long-term indoor VOC concentrations assessment a trend analysis of distribution,disposition, and personal exposure in cohort study samples

Inhalation is one of the entry ports for different chemicals into the human body. In order to investigate this application route and its negative health effect to humans, the presence of volatile organic compounds (VOCs) in indoor air is monitored since many years. To assess global trends and changes of the distribution and disposition of VOCs and the corresponding personal exposure, this study analyzed annual indoor air concentrations collected over a period of 9 (2006–2014) years in the context of a birth control cohort study of 72 VOCs. Additionally, Short Time-series Expression Model (STEM) was used to identify certain correlation for VOCs from different compound classes. For ~42 % of the compounds, a tendency to lower annual median indoor air concentrations was found, and for ~10 % of the VOCs, a trend to higher annual median indoor air concentrations. No such tendencies were observed for ~22 % of the investigated compounds. For ~26 % of the VOCs, the applied linear regression model was not suitable to predict global trends as annual median values were not linearly distributed. Mann-Kendall test was used to (i) confirm the results from the linear regression model and to (ii) calculate trends for those compounds, where linear regression was found to be unsuitable. Thus, for only approximately four of the investigated VOCs, no prediction was possible using both statistical approaches. STEM analysis revealed the connection of benzene, ethylbenzene, m+p xylene, α-pinene, 3-carene, pentadecane, and decamethlycyclopentasiloxane, in addition to the correlation of 1-butanol, chlorobenzene, heptanal, and 2-ethyl-1-hexanol concentrations.     

Characteristics and health impacts of volatile organic compounds in photocopy centers

This study investigates the indoor air quality of typical photocopy centers in Taiwan to evaluate the human health risk following inhalation exposure. Both personal and area samplings were conducted at seven photocopy centers in the Tainan area from July 2002 to March 2003, which covered both summer and winter seasons in Taiwan. The benzene, toluene, ethylbenzene, xylenes, and styrene (BTEXS) measurements indicated no difference between personal and area samplings (P>0.05) and found that air conditioning improves indoor air quality. The additive factor at each photocopy center was significantly below 1.0, based on the current BTEXS permissible exposure limits in Taiwan. However, the mean benzene and styrene levels in the current study were 138 and 18 times, respectively, higher than those in another study conducted in the United States. Comparison of mass ratios of BTEXS with those of several chamber studies revealed that the photocopier is not the only volatile organic compound (VOC) source in photocopy centers. The lifetime cancer and noncancer risks for workers exposed to VOCs were also assessed. Results show that all seven centers in this study had a lifetime cancer risk exceeding 1x10(-6) (ranging from 2.5x10(-3) to 8.5x10(-5)). Regarding noncancer risk, levels of toluene, ethylbenzene, xylenes, and styrene were below the reference levels in all photocopy centers; however, the hazard indices for all still exceeded 1.0 (range 26.2-1.8) because of the high level of benzene in the photocopy centers.     

Asthmatic symptoms and volatile organic compounds, formaldehyde, and carbon dioxide in dwellings.

OBJECTIVES--As a part of the worldwide European Community respiratory health survey, possible relations between symptoms of asthma, building characteristics, and indoor concentration of volatile organic compounds (VOCs) in dwellings were studied. METHODS--The study comprised 88 subjects, aged 20-45 years, from the general population in Uppsala, a mid-Swedish urban community, selected by stratified random sampling. Room temperature, air humidity, respirable dust, carbon dioxide (CO2), VOCs, formaldehyde, and house dust mites were measured in the homes of the subjects. They underwent a structured interview, spirometry, peak expiratory flow (PEF) measurements at home, methacholine provocation test for bronchial hyperresponsiveness, and skin prick tests. In addition, serum concentration of eosinophilic cationic protein (S-ECP), blood eosinophil count, and total immunoglobulin E (S-IgE) were measured. RESULTS--Symptoms related to asthma were more common in dwellings with house dust mites, and visible signs of dampness or microbial growth in the building. Significant relations were also found between nocturnal breathlessness and presence of wall to wall carpets, and indoor concentration of CO2, formaldehyde, and VOCs. The formaldehyde concentration exceeded the Swedish limit value for dwellings (100 micrograms/m3) in one building, and CO2 exceeded the recommended limit value of 1000 ppm in 26% of the dwellings, showing insufficient outdoor air supply. Bronchial hyperresponsiveness was related to indoor concentration of limonene, the most prevalent terpene. Variability in PEF was related to two other terpenes; alpha-pinen and delta-karen. CONCLUSION--Our results suggest that indoor VOCs and formaldehyde may cause asthma-like symptoms. There is a need to increase the outdoor air supply in many dwelling, and wall to wall carpeting and dampness in the building should be avoided. Improved indoor environment can also be achieved by selecting building materials, building construction, and indoor activities on the principle that the emission of volatile organic compounds should be as low as reasonably achievable, to minimise symptoms related to asthma due to indoor air pollution.     

Health effects associated with exposure to residential organic dust

BACKGROUND: This study aimed at relating self-reported health complaints to bioaerosol pollution in the residential outdoor air and to duration of storing organic waste indoors. METHODS: In a cross-sectional study, double blinded to ongoing environmental microbial measurements, physicians collected questionnaires in a neighborhood with a composting site and in unexposed controls. Self-reported prevalence of health complaints, physician diagnoses as well as residential odor annoyance and home hygiene were assessed. RESULTS: An elevation of reports of irritative airway complaints was associated with residency in an area with highest bioaerosol exposure but not with odor annoyance. Longer indoor storage of organic waste was associated with skin related symptoms. Atopic subjects were at higher risk. Airway-related health problems were not associated with longer storage of organic wastes in homes. CONCLUSIONS: Exposure to organic dust in residential air affects airways of residents while exposure in homes due to organic wastes affects the skin.     

Assessment of indoor air pollution in homes with infants

Infants spend most of their indoor time at home; however, residential air quality is poorly understood. We investigated the air quality of infants' homes in the New England area of the U.S. Participants (N = 53) were parents of infants (0-6 months) who completed telephone surveys to identify potential pollutant sources in their residence. Carbon monoxide (CO), carbon dioxide (CO(2)), particulate matter with aerodynamic diameter ≤0.5 μm (PM(0.5)), and total volatile organic compounds (TVOCs) were measured in 10 homes over 4-7 days, and levels were compared with health-based guidelines. Pollutant levels varied substantially across homes and within homes with overall levels for some homes up to 20 times higher than for other homes. Average levels were 0.85 ppm, 663.2 ppm, 18.7 μg/m(3), and 1626 μg/m(3) for CO, CO(2), PM(0.5), and TVOCs, respectively. CO(2), TVOCs, and PM(0.5) levels exceeded health-based indoor air quality guidelines. Survey results suggest that nursery renovations and related potential pollutant sources may be associated with differences in urbanicity, income, and presence of older children with respiratory ailments, which could potentially confound health studies. While there are no standards for indoor residential air quality, our findings suggest that additional research is needed to assess indoor pollution exposure for infants, which may be a vulnerable population.     

Exposure to organic solvents among car painters in Bergen, Norway

Car painters are exposed to organic solvents during their work. Several sets of official regulations have therefore been adopted in Norway in recent years to reduce the exposure. This study evaluated some of the effects of these regulations, by measuring the levels of exposure to organic solvents in six car-painting garages and relating them to the limit values in Norway. Both stationary and personal monitoring were performed. In addition, the occurrence of acute symptoms in the nervous system, skin and upper airways, the use of personal protective equipment and the workers' satisfaction with the ventilation were determined using the results of a questionnaire survey among the car painters from 11 car-painting garages (N=28). A control group of unexposed workers (N=18) was used for comparison. All air samples showed low levels of exposure, far below the limit values. The highest levels were found for toluene; about half the limit value in two garages (11.5 and 12.5 ppm). No significant difference was found between the exposed and unexposed workers in the frequency of acute symptoms. Most workers reported to always use gloves, overalls and respiratory protective equipment during the car painting. The study indicates that the exposure to organic solvents is low in the examined car-painting garages, and the risk of adverse health effects related to organic solvents is probably low in these workplaces.     

Investigation of air pollution in a shopping center and employees' personal exposure level

OBJECTIVES: To investigate the concentrations of chemicals found inside a shopping center (SC), we investigated the condition of air pollution in a SC and the personal exposure level of SC employees. METHODS: The survey was performed in June 2006 in Kyushu. The chemicals studied were volatile organic compounds (VOCs) and aldehydes. The chemicals were collected by a personal passive sampler. RESULT: Thirty-one VOCs and aldehydes were detected inside the SC. The results showed that the concentrations of all the chemicals detected in indoor air were less than those specified in the indoor air quality guideline of Ministry of Health, Labor and Welfare, Japan. The chemical concentrations in the SC decreased in the order of food corner > electric, clothing corner > outdoor and were clearly higher than those outdoors. Therefore, it is thought that the source of chemicals is indoors. The high indoor concentration of 2-ethyl-1-hexanol may be due to diffusion from the walls and floors. In addition, it is suggested that the personal exposure condition of the employees reflected the indoor concentration of each sales floor. The exposure level to formaldehyde was higher at nonworking time than at working time, suggesting that a larger exposure source exists in the place of residence than in the work place. CONCLUSIONS: We found that indoor air quality in SC is maintained at good levels. This might be because of the Japanese strict regulations that require administrations of large-scale buildings to provide adequate ventilation and perform regular measurement of indoor air quality.     

Environmental exposure to volatile organic compounds among workers in Mexico City as assessed by personal monitors and blood concentrations.

Benzene, an important component in gasoline, is a widely distributed environmental contaminant that has been linked to known health effects in animals and humans, including leukemia. In Mexico City, environmental benzene levels, which may be elevated because of the heavy traffic and the poor emission control devices of older vehicles, may pose a health risk to the population. To assess the potential risk, portable passive monitors and blood concentrations were used to survey three different occupational groups in Mexico City. Passive monitors measured the personal exposure of 45 workers to benzene, ethylbenzene, toluene, o-xylene and m-/p-xylene during a work shift. Blood concentrations of the above volatile organic compounds (VOCs), methyl tert-butyl ether, and styrene were measured at the beginning and the end of a work shift. Passive monitors showed significantly higher (p > 0.0001) benzene exposure levels among service station attendants (median = 330 microg/m3; range 130-770) as compared to street vendors (median = 62 microg/m3; range 49-180) and office workers (median = 44 microg/m3, range 32-67). Baseline blood benzene levels (BBLs) for these groups were higher than those reported for similar populations from Western countries (median = 0.63 microg/L, n = 24 for service station attendants; median = 0.30 microg/L, n = 6 for street vendors; and median = 0.17 microgr;g/L, n = 7 for office workers). Nonsmoking office workers who were nonoccupationally exposed to VOCs had BBLs that were more than five times higher than those observed in a nonsmoking U.S. population. BBLs of participants did not increase during the work shift, suggesting that because the participants were chronically exposed to benzene, complex pharmacokinetic mechanisms were involved. Our results highlight the need for more complete studies to assess the potential benefits of setting environmental standards for benzene and other VOCs in Mexico.