Determinants of indoor and personal exposure to PM2.5 of indoor and outdoor origin during the RIOPA study

Effects of physical/environmental factors on fine particle (PM_2.5) exposure, outdoor-to-indoor transport and air exchange rate (AER) were examined. The fraction of ambient PM_2.5 found indoors (F_INF) and the fraction to which people are exposed (α) modify personal exposure to ambient PM_2.5. Because F_INF, α, and AER are infrequently measured, some have used air conditioning (AC) as a modifier of ambient PM_2.5 exposure. We found no single variable that was a good predictor of AER. About 50% and 40% of the variation in F_INF and α, respectively, was explained by AER and other activity variables. AER alone explained 36% and 24% of the variations in F_INF and α, respectively. Each other predictor, including Central AC Operation, accounted for less than 4% of the variation. This highlights the importance of AER measurements to predict F_INF and α. Evidence presented suggests that outdoor temperature and home ventilation features affect particle losses as well as AER, and the effects differ.Total personal exposures to PM_2.5 mass/species were reconstructed using personal activity and microenvironmental methods, and compared to direct personal measurement. Outdoor concentration was the dominant predictor of (partial R² = 30–70%) and the largest contributor to (20–90%) indoor and personal exposures for PM_2.5 mass and most species. Several activities had a dramatic impact on personal PM_2.5 mass/species exposures for the few study participants exposed to or engaged in them, including smoking and woodworking. Incorporating personal activities (in addition to outdoor PM_2.5) improved the predictive power of the personal activity model for PM_2.5 mass/species; more detailed information about personal activities and indoor sources is needed for further improvement (especially for Ca, K, OC). Adequate accounting for particle penetration and persistence indoors and for exposure to non-ambient sources could potentially increase the power of epidemiological analyses linking health effects to particulate exposures.     

Spatial and temporal variability in outdoor,indoor, and personal PM2.5 exposure

Outdoor, indoor and personal PM_2.5 measurements were made in a population of nonsmoking adults from three communities in the Minneapolis–St. Paul metropolitan area between April and November 1999. Thirty-two healthy adult subjects (23 females, 9 males; mean age 42±10, range: 24–64 yr) were monitored for 2–15 days during the spring, summer, and fall monitoring seasons. Twenty-four hour average gravimetric PM_2.5 samples were collected using a federal reference monitor (Anderson RAAS2.5-300) located at outdoor (O) central sites in the Battle Creek (BCK), East St. Paul (ESP) and Phillips (PHI) communities. Concurrent 24-h average indoor (I) and personal (P), and a limited number of outdoor-at-home (O@H) samples were collected using inertial impactors (PEM™ Model 200, MSP, Inc). The O (geometric mean {GM}=8.6; n=271; range: 1.0–41 μg/m³) were lower than I concentrations (GM=10.7; n=294; range 1.3–131 μg/m³), which were lower than P concentrations (GM=19.0; n=332; range 2.2–298 μg/m³). Correlation coefficients between O concentrations in the three communities were high and measured GM O levels in BCK were significantly lower than ESP, most likely because of local sources, but GM concentrations in PHI were not significantly different from BCK or ESP. On days with paired samples (n=29), O concentrations were significantly lower (mean difference 2.9 μg/m³; p=0.026) than O@H measurements (GM=11.3; range: 3.5–33.8 μg/m³), likely due to local sources in communities. Observed I and P concentrations were more variable, probably because of residential central air conditioning and hours of household ventilation for I and P, and occupational and environmental tobacco smoke exposures outside the residence for P. Across all individuals and days the median PM_2.5 “personal cloud” was 5.7 μg/m³, but the mean of the average for each participant was 15.7 μg/m³, with very low values in participants who did not work outside the home and much higher values in subjects with active lifestyles. Across all households and individuals the correlation between P and O concentrations was not significant, but the overall I–O correlation (0.27) and P–I correlation (0.51) were significant (p<0.05). Relatively little spatial variability was observed in O PM_2.5 concentrations across the three communities compared to the variability associated with I and P samples, and the measured O levels were relatively low compared to other large metropolitan areas in the United States.     

Windsor, Ontario exposure assessment study: design and methods validation of personal, indoor, and outdoor air pollution monitoring

The Windsor, Ontario Exposure Assessment Study evaluated the contribution of ambient air pollutants to personal and indoor exposures of adults and asthmatic children living in Windsor, Ontario, Canada. In addition, the role of personal, indoor, and outdoor air pollution exposures upon asthmatic children's respiratory health was assessed. Several active and passive sampling methods were applied, or adapted, for personal, indoor, and outdoor residential monitoring of nitrogen dioxide, volatile organic compounds, particulate matter (PM; PM-2.5 pm [PM2.5] and < or =10 microm [PM10] in aerodynamic diameter), elemental carbon, ultrafine particles, ozone, air exchange rates, allergens in settled dust, and particulate-associated metals. Participants completed five consecutive days of monitoring during the winter and summer of 2005 and 2006. During 2006, in addition to undertaking the air pollution measurements, asthmatic children completed respiratory health measurements (including peak flow meter tests and exhaled breath condensate) and tracked respiratory symptoms in a diary. Extensive quality assurance and quality control steps were implemented, including the collocation of instruments at the National Air Pollution Surveillance site operated by Environment Canada and at the Michigan Department of Environmental Quality site in Allen Park, Detroit, MI. During field sampling, duplicate and blank samples were also completed and these data are reported. In total, 50 adults and 51 asthmatic children were recruited to participate, resulting in 922 participant days of data. When comparing the methods used in the study with standard reference methods, field blanks were low and bias was acceptable, with most methods being within 20% of reference methods. Duplicates were typically within less than 10% of each other, indicating that study results can be used with confidence. This paper covers study design, recruitment, methodology, time activity diary, surveys, and quality assurance and control results for the different methods used.     

Windsor, Ontario exposure assessment study: design and methods validation of personal, indoor, and outdoor air pollution monitoring

The Windsor, Ontario Exposure Assessment Study evaluated the contribution of ambient air pollutants to personal and indoor exposures of adults and asthmatic children living in Windsor, Ontario, Canada. In addition, the role of personal, indoor, and outdoor air pollution exposures upon asthmatic children's respiratory health was assessed. Several active and passive sampling methods were applied, or adapted, for personal, indoor, and outdoor residential monitoring of nitrogen dioxide, volatile organic compounds, particulate matter (PM; PM < or = 2.5 microm [PM2.5] and < or = 10 microm [PM10] in aerodynamic diameter), elemental carbon, ultrafine particles, ozone, air exchange rates, allergens in settled dust, and particulate-associated metals. Participants completed five consecutive days of monitoring during the winter and summer of 2005 and 2006. During 2006, in addition to undertaking the air pollution measurements, asthmatic children completed respiratory health measurements (including peak flow meter tests and exhaled breath condensate) and tracked respiratory symptoms in a diary. Extensive quality assurance and quality control steps were implemented, including the collocation of instruments at the National Air Pollution Surveillance site operated by Environment Canada and at the Michigan Department of Environmental Quality site in Allen Park, Detroit, MI. During field sampling, duplicate and blank samples were also completed and these data are reported. In total, 50 adults and 51 asthmatic children were recruited to participate, resulting in 922 participant days of data. When comparing the methods used in the study with standard reference methods, field blanks were low and bias was acceptable, with most methods being within 20% of reference methods. Duplicates were typically within less than 10% of each other, indicating that study results can be used with confidence. This paper covers study design, recruitment, methodology, time activity diary, surveys, and quality assurance and control results for the different methods used.     

Personal exposure to fine particulate matter in elderly subjects: relation between personal, indoor, and outdoor concentrations

The time-series correlation between ambient levels, indoor levels, and personal exposure to PM2.5 was assessed in panels of elderly subjects with cardiovascular disease in Amsterdam, the Netherlands, and Helsinki, Finland. Subjects were followed for 6 months with biweekly clinical visits. Each subject's indoor and personal exposure to PM2.5 was measured biweekly, during the 24-hr period preceding the clinical visits. Outdoor PM2.5 concentrations were measured at fixed sites. The absorption coefficients of all PM2.5 filters were measured as a marker for elemental carbon (EC). Regression analyses were conducted for each subject separately, and the distribution of the individual regression and correlation coefficients was investigated. Personal, indoor, and ambient concentrations were highly correlated within subjects over time. Median Pearson's R between personal and outdoor PM2.5 was 0.79 in Amsterdam and 0.76 in Helsinki. For absorption, these values were 0.93 and 0.81 for Amsterdam and Helsinki, respectively. The findings of this study provide further support for using fixed-site measurements as a measure of exposure to PM2.5 in epidemiological time-series studies.     

Characterisation of urban inhalation exposures to benzene,formaldehyde and acetaldehyde in the European Union

BACKGROUND, AIM AND SCOPE: All across Europe, people live and work in indoor environments. On average, people spend around 90% of their time indoors (homes, workplaces, cars and public transport means, etc.) and are exposed to a complex mixture of pollutants at concentration levels that are often several times higher than outdoors. These pollutants are emitted by different sources indoors and outdoors and include volatile organic compounds (VOCs), carbonyls (aldehydes and ketones) and other chemical substances often adsorbed on particles. Moreover, legal obligations opposed by legislations, such as the European Union's General Product Safety Directive (GPSD) and Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), increasingly require detailed understanding of where and how chemical substances are used throughout their life-cycle and require better characterisation of their emissions and exposure. This information is essential to be able to control emissions from sources aiming at a reduction of adverse health effects. Scientifically sound human risk assessment procedures based on qualitative and quantitative human exposure information allows a better characterisation of population exposures to chemical substances. In this context, the current paper compares inhalation exposures to three health-based EU priority substances, i.e. benzene, formaldehyde and acetaldehyde. MATERIALS AND METHODS: Distributions of urban population inhalation exposures, indoor and outdoor concentrations were created on the basis of measured AIRMEX data in 12 European cities and compared to results from existing European population exposure studies published within the scientific literature. By pooling all EU city personal exposure, indoor and outdoor concentration means, representative EU city cumulative frequency distributions were created. Population exposures were modelled with a microenvironment model using the time spent and concentrations in four microenvironments, i.e. indoors at home and at work, outdoors at work and in transit, as input parameters. Pooled EU city inhalation exposures were compared to modelled population exposures. The contributions of these microenvironments to the total daily inhalation exposure of formaldehyde, benzene and acetaldehyde were estimated. Inhalation exposures were compared to the EU annual ambient benzene air quality guideline (5 microg/m3-to be met by 2010) and the recommended (based on the INDEX project) 30-min average formaldehyde limit value (30 microg/m3). RESULTS: Indoor inhalation exposure contributions are much higher compared to the outdoor or in-transit microenvironment contributions, accounting for almost 99% in the case of formaldehyde. The highest in-transit exposure contribution was found for benzene; 29.4% of the total inhalation exposure contribution. Comparing the pooled AIRMEX EU city inhalation exposures with the modelled exposures, benzene, formaldehyde and acetaldehyde exposures are 5.1, 17.3 and 11.8 microg/m3 vs. 5.1, 20.1 and 10.2 microg/m3, respectively. Together with the fact that a dominating fraction of time is spent indoors (>90%), the total inhalation exposure is mostly driven by the time spent indoors. DISCUSSION: The approach used in this paper faced three challenges concerning exposure and time-activity data, comparability and scarce or missing in-transit data inducing careful interpretation of the results. The results obtained by AIRMEX underline that many European urban populations are still exposed to elevated levels of benzene and formaldehyde in the inhaled air. It is still likely that the annual ambient benzene air quality guideline of 5 microg/m3 in the EU and recommended formaldehyde 30-min average limit value of 30 microg/m3 are exceeded by a substantial part of populations living in urban areas. Considering multimedia and multi-pathway exposure to acetaldehyde, the biggest exposure contribution was found to be related to dietary behaviour rather than to inhalation. CONCLUSIONS: In the present study, inhalation exposures of urban populations were assessed on the basis of novel and existing exposure data. The indoor residential microenvironment contributed most to the total daily urban population inhalation exposure. The results presented in this paper suggest that a significant part of the populations living in European cities exceed the annual ambient benzene air quality guideline of 5 microg/m3 in the EU and recommended (INDEX project) formaldehyde 30-min average limit value of 30 microg/m3. RECOMMENDATIONS AND PERSPECTIVES: To reduce exposures and consequent health effects, adequate measures must be taken to diminish emissions from sources such as materials and products that especially emit benzene and formaldehyde in indoor air. In parallel, measures can be taken aiming at reducing the outdoor pollution contribution indoors. Besides emission reduction, mechanisms to effectively monitor and manage the indoor air quality should be established. These mechanisms could be developed by setting up appropriate EU indoor air guidelines.     

人体室内外PM_(2.5)吸入暴露研究

介绍了室内外空气颗粒物吸入暴露的评价方法,选择PM2.5作为检测评价的对象,初步评价了上海市某区不同年龄段人员的PM2.5暴露水平。结果表明:(1)成人和老人的全年日平均PM2.5吸入暴露量均较高,并且成人的全年日平均PM2.5吸入暴露量变化曲线和儿童相似。(2)老人室内PM2.5吸入暴露量要明显高于室外,其主要原因是老人在室内时间较长。儿童和成人的室外PM2.5吸入暴露量高于室内。(3)不同人员的年平均PM2.5吸入暴露量的排序为成人老人儿童,其年平均PM2.5吸入暴露量分别为1.141、1.046、0.935mg。     

Residential indoor,outdoor, and workplace concentrations of carbonyl compounds: relationships with personal exposure concentrations and correlation with sources

Personal 48-hr exposures of 15 randomly selected participants as well as microenvironment concentrations in each participant's residence and workplace were measured for 16 carbonyl compounds during summer-fall 1997 as a part of the Air Pollution Exposure Distributions within Adult Urban Populations in Europe (EXPOLIS) study in Helsinki, Finland. When formaldehyde and acetaldehyde were excluded, geometric mean ambient air concentrations outside each participant's residence were less than 1 ppb for all target compounds. Geometric mean residential indoor concentrations of carbonyls were systematically higher than geometric mean personal exposures and indoor workplace concentrations. Additionally, residential indoor/outdoor ratios indicated substantial indoor sources for most target compounds. Carbonyls in residential indoor air correlated significantly, suggesting similar mechanisms of entry into indoor environments. Overall, this study demonstrated the important role of non-traffic-related emissions in the personal exposures of participants in Helsinki and that comprehensive apportionment of population risk to air toxics should include exposure concentrations derived from product emissions and chemical formation in indoor air.     

Exposure assessment of air pollutants: a review on spatial heterogeneity and indoor/outdoor/personal exposure to suspended particulate matter,nitrogen dioxide and ozone

This review describes databases of small-scale spatial variations and indoor, outdoor and personal measurements of air pollutants with the main focus on suspended particulate matter, and to a lesser extent, nitrogen dioxide and photochemical pollutants. The basic definitions and concepts of an exposure measurement are introduced as well as some study design considerations and implications of imprecise exposure measurements. Suspended particulate matter is complex with respect to particle size distributions, the chemical composition and its sources. With respect to small-scale spatial variations in urban areas, largest variations occur in the ultrafine (<0.1 μm) and the coarse mode (PM_10–2.5, resuspended dust). Secondary aerosols which contribute to the accumulation mode (0.1–2 μm) show quite homogenous spatial distribution. In general, small-scale spatial variations of PM_2.5 were described to be smaller than the spatial variations of PM₁₀. Recent studies in outdoor air show that ultrafine particle number counts have large spatial variations and that they are not well correlated to mass data. Sources of indoor particles are from outdoors and some specific indoor sources such as smoking and cooking for fine particles or moving of people (resuspension of dust) for coarse particles. The relationships between indoor, outdoor and personal levels are complex. The finer the particle size, the better becomes the correlation between indoor, outdoor and personal levels. Furthermore, correlations between these parameters are better in longitudinal analyses than in cross-sectional analyses. For NO₂ and O₃, the air chemistry is important. Both have considerable small-scale spatial variations within urban areas. In the absence of indoor sources such as gas appliances, NO₂ indoor/outdoor relationships are strong. For ozone, indoor levels are quite small. The study hypothesis largely determines the choice of a specific concept in exposure assessment, i.e. whether personal sampling is needed or if ambient monitoring is sufficient. Careful evaluation of the validity and improvements in precision of an exposure measure reduce error in the measurements and bias in the exposure–effect relationship.     

VOC concentrations measured in personal samples and residential indoor,outdoor and workplace microenvironments in EXPOLIS-Helsinki,Finland

Thirty target volatile organic compounds (VOC) were analyzed in personal 48-h exposure samples and residential indoor, residential outdoor and workplace indoor microenvironment samples as a component of EXPOLIS-Helsinki, Finland. Geometric mean residential indoor concentrations were higher than geometric mean residential outdoor concentrations for all target compounds except hexane, which was detected in 40% of residential outdoor samples and 11% of residential indoor samples, respectively. Geometric mean residential indoor concentrations were significantly higher than personal exposure concentrations, which in turn were significantly higher than workplace concentrations for compounds that had strong residential indoor sources (d-limonene, alpha pinene, 3-carene, hexanal, 2-methyl-1-propanol and 1-butanol). 40% of participants in EXPOLIS-Helsinki reported personal exposure to environmental tobacco smoke (ETS). Participants in Helsinki that were exposed to ETS at any time during the 48-h sampling period had significantly higher personal exposures to benzene, toluene, styrene, m,p-xylene, o-xylene, ethylbenzene and trimethylbenzene. Geometric mean ETS-free workplace concentrations were higher than ETS-free personal exposure concentrations for styrene, hexane and cyclohexane. Geometric mean personal exposures of participants not exposed to ETS were approximately equivalent to time weighted ETS-free indoor and workplace concentrations, except for octanal and compounds associated with traffic, which showed higher geometric mean personal exposure concentrations than any microenvironment (o-xylene, ethylbenzene,benzene, undecane, nonane, decane, m,p-xylene, and trimethylbenzene). Considerable differences in personal exposure concentrations and residential levels of compounds with mainly indoor sources suggested differences in product types or the frequency of product use between Helsinki, Germany and the United States.     

VOC source identification from personal and residential indoor,outdoor and workplace microenvironment samples in EXPOLIS-Helsinki,Finland

Principal component analyses (varimax rotation) were used to identify common sources of 30 target volatile organic compounds (VOCs) in residential outdoor, residential indoor and workplace microenvironment and personal 48-h exposure samples, as a component of the EXPOLIS-Helsinki study. Variability in VOC concentrations in residential outdoor microenvironments was dominated by compounds associated with long-range transport of pollutants, followed by traffic emissions, emissions from trees and product emissions. Variability in VOC concentrations in environmental tobacco smoke (ETS) free residential indoor environments was dominated by compounds associated with indoor cleaning products, followed by compounds associated with traffic emissions, long-range transport of pollutants and product emissions. Median indoor/outdoor ratios for compounds typically associated with traffic emissions and long-range transport of pollutants exceeded 1, in some cases quite considerably, indicating substantial indoor source contributions. Changes in the median indoor/outdoor ratios during different seasons reflected different seasonal ventilation patterns as increased ventilation led to dilution of those VOC compounds in the indoor environment that had indoor sources. Variability in workplace VOC concentrations was dominated by compounds associated with traffic emissions followed by product emissions, long-range transport and air fresheners. Variability in VOC concentrations in ETS free personal exposure samples was dominated by compounds associated with traffic emissions, followed by long-range transport, cleaning products and product emissions. VOC sources in personal exposure samples reflected the times spent in different microenvironments, and personal exposure samples were not adequately represented by any one microenvironment, demonstrating the need for personal exposure sampling.     

Personal exposure levels and microenvironmental concentrations of formaldehyde and acetaldehyde in the Helsinki metropolitan area, Finland

Personal 48-hr exposures to formaldehyde and acetaldehyde of 15 randomly selected participants were measured during the summer/autumn of 1997 using Sep-Pak DNPH-Silica cartridges as a part of the EXPOLIS study in Helsinki, Finland. In addition to personal exposures, simultaneous measurements of microenvironmental concentrations were conducted at each participant's residence (indoor and outdoor) and workplace. Mean personal exposure levels were 21.4 ppb for formaldehyde and 7.9 ppb for acetaldehyde. Personal exposures were systematically lower than indoor residential concentrations for both compounds, and ambient air concentrations were lower than both indoor residential concentrations and personal exposure levels. Mean workplace concentrations of both compounds were lower than mean indoor residential concentrations. Correlation between personal exposures and indoor residential concentrations was statistically significant for both compounds. This indicated that indoor residential concentrations of formaldehyde and acetaldehyde are a better estimate of personal exposures than are concentrations in ambient air. In addition, a time-weighted exposure model did not improve the estimation of personal exposures above that obtained using indoor residential concentrations as a surrogate for personal exposures. Correlation between formaldehyde and acetaldehyde was statistically significant in outdoor microenvironments, suggesting that both compounds have similar sources and sinks in ambient urban air.     

Source apportionment of indoor, outdoor, and personal PM2.5 in Seattle, Washington, using positive matrix factorization

As part of a large exposure assessment and health-effects panel study, 33 trace elements and light-absorbing carbon were measured on 24-hr fixed-site filter samples for particulate matter with an aerodynamic diameter <2.5 microm (PM2.5) collected between September 26, 2000, and May 25, 2001, at a central outdoor site, immediately outside each subject's residence, inside each residence, and on each subject (personal sample). Both two-way (PMF2) and three-way (PMF3) positive matrix factorization were used to deduce the sources contributing to PM2.5. Five sources contributing to the indoor and outdoor samples were identified: vegetative burning, mobile emissions, secondary sulfate, a source rich in chlorine, and a source of crustal-derived material. Vegetative burning contributed more PM2.5 mass on average than any other source in all microenvironments, with average values estimated by PMF2 and PMF3, respectively, of 7.6 and 8.7 microg/m3 for the outdoor samples, 4 and 5.3 microg/m3 for the indoor samples, and 3.8 and 3.4 microg/m3 for the personal samples. Personal exposure to the combustion-related particles was correlated with outdoor sources, whereas exposure to the crustal and chlorine-rich particles was not. Personal exposures to crustal sources were strongly associated with personal activities, especially time spent at school among the child subjects.     

DEARS particulate matter relationships for personal,indoor, outdoor,and central site settings for a general population

This analysis provides the initial summary of PM_2.5 mass concentrations relationships for all seasons and participants for a general population in the Detroit Exposure and Aerosol Research Study (DEARS). The summary presented highlights the utility of the new methodologies applied, in addition to summarizing the particulate matter (PM) data.Results include the requirement to adjust the exposure data for monitor wearing compliance and measured environmental tobacco smoke (ETS) levels, even though the study design specified a non-smoking household. A 40% wearing compliance acceptance level was suggested as necessary to balance minimizing exposure misclassification (from poor compliance) and having sufficient data to conduct robust statistical analyses. An ETS threshold level equivalent to adding more than 1.5 μg m^?3 to the collected sample was found to be necessary to detect changes in the personal exposure factor (F_pex). It is not completely clear why such a large threshold level was necessary.Statistically significant spatial PM_2.5 gradients were identified in three of the six DEARS neighborhoods in Wayne County. These were expected, given the number of strong, localized PM sources in the Detroit (Michigan) metro area. Some residential outdoor bias levels compared with the central site at Allen Park exceeded 15%. After adjusting for ETS biases, the outdoor contributions to the personal exposure were typically larger by factors from 1.75 to 2.2 compared with those of the non-outdoor sources. The outdoor contribution was larger in the summer than in the winter, which is consistent with the fractions of time spent outdoors in the summer vs. the winter (6.7% vs. 1.1% of the time).Mean personal PM_2.5 cloud levels for the general population DEARS cohort ranged from 1.5 to 3.8 (after ETS adjustment) and were comparable to those reported previously. The personal exposure collections indoors were typically at least 13 times greater than those contributed outdoors.     

Monitoring personal,indoor, and outdoor exposures to metals in airborne particulate matter: Risk of contamination during sampling,handling and analysis

Rigorous sampling and quality assurance protocols are required for the reliable measurement of personal, indoor and outdoor exposures to metals in fine particulate matter (PM_2.5). Testing of five co-located replicate air samplers assisted in identifying and quantifying sources of contamination of filters in the laboratory and in the field. A field pilot study was conducted in Windsor, Ont., Canada to ascertain the actual range of metal content that may be obtained on filter samples using low-flow (4 L min⁻¹) 24-h monitoring of personal, indoor and outdoor air. Laboratory filter blanks and NIST certified reference materials were used to assess contamination, instrument performance, accuracy and precision of the metals determination. The results show that there is a high risk of introducing metal contamination during all stages of sampling, handling and analysis, and that sources and magnitude of contamination vary widely from element to element. Due to the very small particle masses collected on low-flow 24-h filter samples (median 0.107 mg for a sample volume of approximately 6 m³) the contribution of metals from contamination commonly exceeds the content of the airborne particles being sampled. Thus, the use of field blanks to ascertain the magnitude and variability of contamination is critical to determine whether or not a given element should be reported. The results of this study were incorporated into standard operating procedures for a large multiyear personal, indoor and outdoor air monitoring campaign in Windsor.     

室内甲醛污染治理实验研究

针对装修所带来的室内甲醛污染危害,采用活性炭、甲醛清除剂来去除室内甲醛,并对其去除效果、影响因素进行了研究。结果表明,在活性炭、甲醛清除剂最佳使用量下,甲醛清除剂的去除率显著高于活性炭去除率,且持久性较好;最佳量的甲醛清除剂在治理不同板材所含的甲醛时,中密度板的甲醛去除率均高于木板、细木工板和装饰单面贴面胶合板的去除率;环境温度升高时,甲醛清除剂其去除效率有所降低。甲醛清除剂对室内甲醛有明显的去除。     

Polycyclic aromatic hydrocarbons in indoor and outdoor air in Turkey: Estimations of sources and exposure

The aim of the current study was to measure polycyclic aromatic hydrocarbons (PAHs) in eight indoor (In both kitchen and living room) air sampling locations using a passive sampling method for collection. Passive outdoor air samples were also collected from 3 of the same sampling locations as the indoor air sampling sites. Sampling was conducted in three seasons. The summer season, when windows are generally open, was between 18th July and 01st September, 2014; the autumn and winter seasons, when windows are mostly closed, was between 18^th October and 01^st December, 2014, and 01^st December, 2014, and 18^th January, 2015, respectively.

Average PAH concentrations in summer were 22 ± 21 ng/m³ and 17 ± 12 ng/m³ in the living room and kitchen, respectively, whereas living room and kitchen average PAH concentrations were 23 ± 16 ng/m³ and 20 ± 9 ng/m³, respectively, in autumn and 23 ± 13 ng/m³ and 23 ± 24 ng/m³, respectively, in winter. Outdoor air PAH concentrations in summer, autumn and winter were 7 ± 0.4 ng/m³, 22 ± 13 ng/m³ and 209 ± 33 ng/m³, respectively. An increase in outdoor PAH concentrations was measured in winter compared to the concentrations in summer and autumn, which paralleled the lower outdoor air temperature. However, PAH concentrations in the indoor environment vary according to the household characteristics and personal habits.     

Comparative study on indoor air quality in Japan and China: Characteristics of residential indoor and outdoor VOCs

We conducted a comparative study on the indoor air quality for Japan and China to investigate aromatic volatile organic compounds (VOCs) in indoor microenvironments (living room, bedroom, and kitchen) and outdoors in summer and winter during 2006–2007. Samples were taken from Shizuoka in Japan and Hangzhou in China, which are urban cities with similar latitudes. Throughout the samplings, the indoor and outdoor concentrations of many of the targeted VOCs (benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes) in China were significantly higher than those in Japan. The indoor concentrations of VOCs in Japan were somewhat consistent with those outdoors, whereas those in China tended to be higher than those outdoors. Here, we investigated the differences in VOC concentrations between Japan and China. Compositional analysis of indoor and outdoor VOCs showed bilateral differences; the contribution of benzene in China was remarkably higher than that in Japan. Significant correlations (p < 0.05) for benzene were observed among the concentrations in indoor microenvironments and between the outdoors and living rooms or kitchens in Japan. In China, however, significant correlations were observed only between living rooms and bedrooms. These findings suggest differences in strengths of indoor VOC emissions between Japan and China. The source characterizations were also investigated using principal component analysis/absolute principal component scores. It was found that outdoor sources including vehicle emission and industrial sources, and human activity could be significant sources of indoor VOC pollution in Japan and China respectively. In addition, the lifetime cancer risks estimated from unit risks and geometric mean indoor concentrations of carcinogenic VOCs were 2.3 × 10^?5 in Japan and 21 × 10^?5 in China, indicating that the exposure risks in China were approximately 10 times higher than those in Japan.     

Evaluation of airborne particulate matter and metals data in personal,indoor and outdoor environments using ED-XRF and ICP-MS and co-located duplicate samples

Factors and sources affecting measurement uncertainty associated with monitoring metals in airborne particulate matter (PM) were investigated as part of the Windsor, Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate samples and a comparison of two analytical approaches: ED-XRF and ICP-MS. Sampling variability was estimated using relative percent difference (RPD) of co-located duplicate samples. The comparison of ICP-MS and ED-XRF results yields very good correlations (R² ≥ 0.7) for elements present at concentrations that pass both ICP-MS and ED-XRF detection limits (e.g. Fe, Mn, Zn, Pb and Cu). PM concentration ranges (median, sample number) of 24-h indoor PM₁₀ and personal PM₁₀ filters, and outdoor PM_2.5 filters were determined to be 2.2–40.7 (11.0, n = 48) μg m^?3, 8.0–48.3 (11.9, n = 48) μg m^?3, and 17.1–42.3 (21.6, n = 18) μg m^?3, respectively. The gravimetric analytical results reveal that the variations in PM mass measurements for same-day sampling are insignificant compared to temporal or spatial variations: 92%, 100% and 96% of indoor, outdoor and personal duplicate samples, respectively, pass the quality criteria (RPD ≤ 20%). Uncertainties associated with ED-XRF elemental measurements of S, Ca, Mn, Fe and Zn for 24-h filter samples are low: 78%–100% of the duplicate samples passed the quality criteria. In the case of 24-h filter samples using ICP-MS, more elements passed the quality criteria due to the lower detection limits. These were: Li, Na, K, Ca, Si, Al, V, Fe, Mn, Co, Cu, Mo, Ag, Zn, Pb, As, Mg, Sb, Sn, Sr, Th, Ti, Tl, and U. Low air concentrations of metals (near or below instrumental detection limits) and/or inadvertent introduction of metal contamination are the main causes for excluding elements based on the pass/fail criteria. Uncertainty associated with elemental measurements must be assessed on an element-by-element basis.