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1.
Indoor Air ; 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420890

RESUMO

This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously ventilated climate chamber at two air exchange rates (1 h-1 and 3 h-1 ) and two initial ozone mixing ratios (30 and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A time-of-flight-chemical ionization mass spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the t-shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation.

2.
Indoor Air ; 29(4): 604-615, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31077433

RESUMO

Reducing indoor ozone levels may be an effective strategy to reduce total exposure and associated mortality. Here we estimate (a) premature mortalities attributable to ozone for China's urban population ≥25 years of age; (b) the fraction of total exposure occurring indoors; and (c) mortalities that can be potentially avoided through meeting current and more stringent indoor ozone standards/guidelines based on 1-hour daily maxima. To estimate ozone-attributable premature mortalities, we used hourly outdoor ozone concentrations measured at 1497 monitoring stations located in 339 Chinese cities and a published concentration-response model. We proceeded to estimate province-specific infiltration factors and co-occurring hourly indoor ozone concentrations. For the year 2015, we estimated that indoor exposures accounted for 59% (95% confidence interval (CI): 26%-79%) of the total ozone exposure that resulted in 70800 (95% CI: 35 900-137 700) premature all-cause mortalities in urban China. If the current Chinese indoor ozone standards (80 ppbv (160 µg/m3 ); 56 ppbv (112 µg/m3 )) were met, the mean estimates of reduction in mortalities would be indistinguishable from zero. With stricter 1-hour indoor ozone guidelines, the expected mortality reductions increase exponentially per unit decrease in indoor ozone. The analysis in this paper should help facilitate formulating present and future indoor ozone guidelines.

3.
Environ Sci Technol ; 53(10): 5559-5575, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31034216

RESUMO

A growing body of evidence identifies clothing as an important mediator of human exposure to chemicals and particles, which may have public health significance. This paper reviews and critically assesses the state of knowledge regarding how clothing, during wear, influences exposure to molecular chemicals, abiotic particles, and biotic particles, including microbes and allergens. The underlying processes that govern the acquisition, retention, and transmission of clothing-associated contaminants and the consequences of these for subsequent exposures are explored. Chemicals of concern have been identified in clothing, including byproducts of their manufacture and chemicals that adhere to clothing during use and care. Analogously, clothing acts as a reservoir for biotic and abiotic particles acquired from occupational and environmental sources. Evidence suggests that while clothing can be protective by acting as a physical or chemical barrier, clothing-mediated exposures can be substantial in certain circumstances and may have adverse health consequences. This complex process is influenced by the type and history of the clothing; the nature of the contaminant; and by wear, care, and storage practices. Future research efforts are warranted to better quantify, predict, and control clothing-related exposures.


Assuntos
Vestuário , Exposição Ambiental , Poluentes Ambientais , Humanos
4.
Environ Sci Process Impacts ; 21(8): 1268-1279, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-30944918

RESUMO

Emerging investigator series: Phthalate esters are present at elevated concentrations in floor dust, and resuspension of dust represents a major source for human exposure to chemicals. Biodegradation of phthalates occurs in aquatic systems and soils but has not been demonstrated in house dust. The goal of this study was to quantify indoor phthalate ester degradation through both biotic and abiotic mechanisms. Worn carpet squares were embedded with dust and incubated for one to six weeks at equilibrium relative humidity (ERH) levels of 50, 80, 85, 90, 95, and 100%, and nine phthalates were measured. Removal was observed for DEHP, BBzP, DINP, DiDP, and DMP (p < 0.05) when incubated under elevated relative humidity conditions. Abiotic and biotic losses were examined separately using dust spiked with deuterated di(2-ethylhexyl)phthalate (d-DEHP) that was embedded in carpet and incubated at 100% ERH. Abiotic processes resulted in a 10.1% (±1.1%, standard error) to 69.6% (±4.8%) decrease in total d-DEHP after one week (p = 0.03) and a 27.2% (±1.4%) to 52.0% (±2.1%) decrease after three weeks (p = 0.008). Biodegradation resulted in a decrease in total d-DEHP after one week, ranging from 5.9% (±8.9%) to 8.5% (±1.7%) (p = 0.07) and a 1.7% (±3.9%) to 10.3% (±4.5%) decrease after three weeks (p = 0.044). Metatranscriptomic-based analysis indicates that fungi found in carpet dust express genes capable of degrading phthalate esters via various biochemical processes (including ß-oxidation and hydrolysis). Overall, these results support the hypothesis that phthalate losses in floor dust are due to a combination of abiotic and microbial degradation at ≥80% ERH.

5.
Environ Sci Technol ; 53(6): 3119-3127, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30794390

RESUMO

This study estimates adult mortalities attributed to PM2.5 across urban China in 2015 and the corresponding mortalities that might be avoided by meeting the yearly averaged indoor PM2.5 threshold in the newly established Assessment Standard for Healthy Building (ASHB) and seven other potential thresholds. We use outdoor PM2.5 concentrations from ∼1500 monitoring sites in 339 Chinese cities, coupled with a detailed exposure model, to estimate outdoor and indoor exposures to PM2.5 originating outdoors. We proceed to calculate premature mortality attributable to PM2.5 exposure using an integrated exposure-response model. Results indicate that indoor exposures accounted for 66%-87% of total exposure to PM2.5 of outdoor origin and 81% (95% confidence interval (CI), 71%-87%), i.e., 316 000 (95% CI, 176 000-435 000), of the 389 000 (95% CI, 245 000-501 000) mortalities attributable to "outdoor PM2.5" for the urban population ≥25 years of age in China in 2015. Potentially 14 000 (95% CI, 8000-20 000) deaths might be avoided if indoor PM2.5 of outdoor origin met the ASHB guideline of 35 µg/m3 for annual mean indoor PM2.5, and 162 000 (95% CI, 79 000-237 000) deaths might be avoided by meeting a 10 µg/m3 threshold. The analysis in this work should be helpful in formulating indoor air quality policies.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Adulto , China , Cidades , Monitoramento Ambiental , Humanos , Material Particulado
6.
J Thorac Dis ; 10(7): 4643-4652, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30174917

RESUMO

Background: Studies have suggested that age increases susceptibility to ozone-associated mortality, but the underlying mechanisms are unclear. In a previous study, personal exposure to ozone was significantly associated with a platelet activation biomarker, plasma soluble P-selectin (sCD62P), and blood pressure in 89 healthy adults, aged 22-52 years. The present study examines whether age modifies these associations in the same adults and in additional adults. Methods: Interaction terms of age and exposure were analyzed using hierarchical Bayesian mixed effects ridge regressions. Data from a similar additional study involving 71 healthy participants, aged 19-26 years, were pooled with the data from the first study to evaluate age effect modification when more young adults were added to the analysis. Results: In the 89 adults, significant age interactions were observed for past 24-hour and 2-week ozone exposures and sCD62P. Based on the pooled data (89 plus 71 adults), a 10 ppb increase in 24-hour ozone exposure was associated with increases in sCD62P and systolic blood pressure (SBP) by 22.3% (95% CI: 14.3%, 31.2%) and 1.35 (-0.18, 2.84) mmHg, respectively, at age 25; these values increased to 48.6% (32.7%, 65.1%) and 4.98 (2.56, 7.35) mmHg, respectively, at age 40. Conclusions: These results mechanistically suggest that increasing age enhances cardiovascular effects of ozone.

7.
Angew Chem Int Ed Engl ; 57(38): 12228-12263, 2018 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-29537125

RESUMO

There is an ongoing probing of the role of chemicals in the indoor environment. The majority of potential target substances are so-called very volatile, volatile, and semi-volatile organic compounds (VVOCs, VOCs, and SVOCs). Depending on their physical properties and the mass transfer conditions, they are distributed in or between the gas phase, particle phase, settled house dust, surface films, clothing, and other fabrics as well as the exposed skin and hair of the occupants themselves. Therefore, inhalation, ingestion, and dermal uptake all must be considered as relevant pathways for exposure assessment in human habitats. Exposure to VVOCs, VOCs, and SVOCs can be estimated by measuring their concentrations in relevant indoor compartments or by determining the amounts of the target compounds and/or their metabolites in urine and blood. Assessing the various routes of exposure often requires a combination of sophisticated and interdisciplinary theoretical background and experimental techniques. Consequently, close communication and collaboration between chemical and exposure scientists are needed to achieve a better understanding of human exposure to chemical substances in various indoor environments. Embedded in the toxicological context, this is the basis for assessing the corresponding health risks and for determining control strategies or approaches to limit such risks.

8.
Environ Int ; 114: 27-36, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29475121

RESUMO

BACKGROUND: More than 90% of the world's population lives in areas where outdoor air pollution levels exceed health-based limits. In these areas, individuals may use indoor air filtration, often on a sporadic basis, in their residences to reduce exposure to respirable particles (PM2.5). Whether this intervention can lead to improvements in health outcomes has not been evaluated. METHODS: Seventy non-smoking healthy adults, aged 19 to 26 years, received both true and sham indoor air filtration in a double-blinded randomized crossover study. Each filtration session was approximately 13 h long. True and sham filtration sessions were separated by a two-week washout interval. The study was carried out in a suburb of Shanghai. RESULTS: During the study period, outdoor PM2.5 concentrations ranged from 18.6 to 106.9 µg/m3, which overlapped with levels measured in Western Europe and North America. Compared to sham filtration, true filtration on average decreased indoor PM2.5 concentration by 72.4% to 10.0 µg/m3 and particle number concentration by 59.2% to 2316/cm3. For lung function measured immediately after the end of filtration, true filtration significantly lowered airway impedance at 5 Hz (Z5) by 7.1% [95% CI: 2.4%, 11.9%], airway resistance at 5 Hz (R5) by 7.4% [95% CI: 2.4%, 12.5%], and small airway resistance (R5-R20) by 20.3% [95% CI: 0.1%, 40.5%], reflecting improved airway mechanics especially for the small airways. However, no significant improvements for spirometry indicators (FEV1, FVC) were observed. True filtration also significantly lowered von Willebrand factor (VWF) by 26.9% [95% CI: 7.3%, 46.4%] 24 h after the end of filtration, indicating reduced risk for thrombosis. Stratified analysis in male and female participants showed that true filtration significantly decreased pulse pressure by 3.3% [95% CI: 0.8%, 7.4%] in females, and significantly reduced VWF by 42.4% [95% CI: 17.4%, 67.4%] and interleukin-6 by 22.6% [95% CI: 0.4%, 44.9%] in males. Effect modification analyses indicated that filtration effects in male and female participants were not significantly different. CONCLUSION: A single overnight residential air filtration, capable of reducing indoor particle concentrations substantially, can lead to improved airway mechanics and reduced thrombosis risk.

9.
Environ Sci Technol ; 52(5): 2419-2428, 2018 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-29402076

RESUMO

This review aims to encapsulate the importance, ubiquity, and complexity of indoor chemistry. We discuss the many sources of indoor air pollutants and summarize their chemical reactions in the air and on surfaces. We also summarize some of the known impacts of human occupants, who act as sources and sinks of indoor chemicals, and whose activities (e.g., cooking, cleaning, smoking) can lead to extremely high pollutant concentrations. As we begin to use increasingly sensitive and selective instrumentation indoors, we are learning more about chemistry in this relatively understudied environment.

10.
Environ Sci Technol ; 51(19): 11371-11379, 2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28858503

RESUMO

Benzophenone-3 (also known as BP-3 or oxybenzone) is added to sunscreens, plastics, and some coatings to filter UV radiation. The suspected endocrine disruptor BP-3 has been detected in the air and settled dust of homes and is expected to redistribute from its original sources to other indoor compartments, including clothing. Given its physical and chemical properties, we hypothesized that dermal uptake from clothing could contribute to the body burden of this compound. First, cotton shirts were exposed to air at an elevated concentration of BP-3 for 32 days; the final air concentration was 4.4 µg/m3. Next, three participants wore the exposed shirts for 3 h. After 3 h of exposure, participants wore their usual clothing during the collection of urine samples for the next 48 h. Urine was analyzed for BP-3, a metabolite (BP-1), and six other UV filters. The rate of urinary excretion of the sum of BP-1 and BP-3 increased for all participants during and following the 3 h of exposure. The summed mass of BP-1 and BP-3 excreted during the first 24 h attributable to wearing exposed t-shirts were 12, 9.9, and 82 µg for participants 1, 2, and 3, respectively. Analysis of these results, coupled with predictions of steady-state models, suggest that dermal uptake of BP-3 from clothing could meaningfully contribute to overall body burden.


Assuntos
Benzofenonas/farmacocinética , Vestuário , Protetores Solares/farmacocinética , Adulto , Benzofenonas/urina , Disruptores Endócrinos , Feminino , Humanos , Masculino
11.
JAMA Intern Med ; 177(9): 1344-1353, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28715576

RESUMO

Importance: Exposure to ozone has been associated with cardiovascular mortality, but the underlying biological mechanisms are not yet understood. Objective: To examine the association between ozone exposure and cardiopulmonary pathophysiologic mechanisms. Design, Setting, and Participants: A longitudinal study involving 89 healthy adult participants living on a work campus in Changsha City, China, was conducted from December 1, 2014, to January 31, 2015. This unique quasiexperimental setting allowed for better characterization of air pollutant exposure effects because the participants spent most of their time in controlled indoor environments. Concentrations of indoor and outdoor ozone, along with the copollutants particulate matter, nitrogen dioxide, and sulfur dioxide, were monitored throughout the study period and then combined with time-activity information and filtration conditions of each residence and office to estimate 24-hour and 2-week combined indoor and outdoor mean exposure concentrations. Associations between each exposure measure and outcome measure were analyzed using single-pollutant and 2-pollutant linear mixed models controlling for ambient temperature, secondhand smoke exposure, and personal-level time-varying covariates. Main Outcomes and Measures: Biomarkers indicative of inflammation and oxidative stress, arterial stiffness, blood pressure, thrombotic factors, and spirometry were measured at 4 sessions. Results: Of the 89 participants, 25 (28%) were women and the mean (SD) age was 31.5 (7.6) years. The 24-hour ozone exposure concentrations ranged from 1.4 to 19.4 parts per billion (ppb), corresponding to outdoor concentrations ranging from 4.3 to 47.9 ppb. Within this range, in models controlling for a second copollutant and other potential confounders, a 10-ppb increase in 24-hour ozone was associated with mean increases of 36.3% (95% CI, 29.9%-43.0%) in the level of platelet activation marker soluble P-selectin, 2.8% (95% CI, 0.6%-5.1%) in diastolic blood pressure, 18.1% (95% CI, 4.5%-33.5%) in pulmonary inflammation markers fractional exhaled nitric oxide, and 31.0% (95% CI, 0.2%-71.1%) in exhaled breath condensate nitrite and nitrate as well as a -9.5% (95% CI, -17.7% to -1.4%) decrease in arterial stiffness marker augmentation index. A 10-ppb increase in 2-week ozone was associated with increases of 61.1% (95% CI, 37.8%-88.2%) in soluble P-selectin level and 126.2% (95% CI, 12.1%-356.2%) in exhaled breath condensate nitrite and nitrate level. Other measured biomarkers, including spirometry, showed no significant associations with either 24-hour ozone or 2-week ozone exposures. Conclusions and Relevance: Short-term ozone exposure at levels not associated with lung function changes was associated with platelet activation and blood pressure increases, suggesting a possible mechanism by which ozone may affect cardiovascular health.


Assuntos
Doenças Cardiovasculares , Exposição Ambiental , Nitratos/análise , Nitritos/análise , Ozônio , Pneumonia , Adulto , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Poluição do Ar/prevenção & controle , Testes Respiratórios/métodos , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/fisiopatologia , China/epidemiologia , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Exposição Ambiental/prevenção & controle , Feminino , Humanos , Masculino , Dióxido de Nitrogênio , Estresse Oxidativo , Ozônio/efeitos adversos , Ozônio/análise , Pneumonia/diagnóstico , Pneumonia/epidemiologia , Pneumonia/metabolismo , Pneumonia/fisiopatologia , Tempo de Protrombina/métodos , Espirometria/métodos , Rigidez Vascular
12.
Environ Sci Technol ; 51(16): 9089-9100, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28682605

RESUMO

Exposure to fine particulate matter (PM2.5) from indoor and outdoor sources is a leading environmental contributor to global disease burden. In response, we established under the auspices of the UNEP/SETAC Life Cycle Initiative a coupled indoor-outdoor emission-to-exposure framework to provide a set of consistent primary PM2.5 aggregated exposure factors. We followed a matrix-based mass balance approach for quantifying exposure from indoor and ground-level urban and rural outdoor sources using an effective indoor-outdoor population intake fraction and a system of archetypes to represent different levels of spatial detail. Emission-to-exposure archetypes range from global indoor and outdoor averages, via archetypal urban and indoor settings, to 3646 real-world cities in 16 parametrized subcontinental regions. Population intake fractions from urban and rural outdoor sources are lowest in Northern regions and Oceania and highest in Southeast Asia with population-weighted means across 3646 cities and 16 subcontinental regions of, respectively, 39 ppm (95% confidence interval: 4.3-160 ppm) and 2 ppm (95% confidence interval: 0.2-6.3 ppm). Intake fractions from residential and occupational indoor sources range from 470 ppm to 62 000 ppm, mainly as a function of air exchange rate and occupancy. Indoor exposure typically contributes 80-90% to overall exposure from outdoor sources. Our framework facilitates improvements in air pollution reduction strategies and life cycle impact assessments.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Material Particulado , Poluição do Ar , Cidades , Monitoramento Ambiental , Humanos , Tamanho da Partícula
13.
Environ Sci Technol ; 51(11): 6220-6228, 2017 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-28452220

RESUMO

Inhaled semivolatile organic compounds (SVOCs) are simultaneously present in gas and particle phases. Particles desorb a fraction of their SVOCs moving through the human respiratory tract (RT). Quantifying such desorption is challenging but important since gas- and particle-phase SVOCs deposit in different locations in the RT, encountering different cell populations with varying health consequences. This paper presents a mass transfer model to quantify this desorption process in the head, tracheobronchial, and alveolar regions of the RT. The desorption of SVOCs from inhaled particles can be gauged using the ratio of particle residence time to the time required to achieve particle/gas equilibrium. Results indicate that the larger this ratio is, the more likely particles desorb the SVOCs they carry. For particles smaller than 0.5 µm diameter and SVOCs with a particle/gas partition coefficient (unitless) of 1010, accounting for desorption reduces the estimated particle-phase SVOC concentrations in the alveolar region by more than 35%; the reduction is almost 700% for 0.05 µm diameter particles. In hypothetical scenarios representing common indoor and outdoor situations, neglecting desorption significantly overestimates the concentration of ultrafine particle associated SVOCs in the alveolar region. This model is a preliminary step toward more nuanced estimates of exposure to inhaled SVOCs.


Assuntos
Poluentes Atmosféricos/farmacocinética , Sistema Respiratório , Compostos Orgânicos Voláteis/farmacocinética , Poluição do Ar em Ambientes Fechados , Habitação , Humanos , Modelos Biológicos
14.
Environ Sci Technol ; 51(5): 2519-2528, 2017 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-28169528

RESUMO

Laboratory studies of atmospheric chemistry characterize the nature of atmospherically relevant processes down to the molecular level, providing fundamental information used to assess how human activities drive environmental phenomena such as climate change, urban air pollution, ecosystem health, indoor air quality, and stratospheric ozone depletion. Laboratory studies have a central role in addressing the incomplete fundamental knowledge of atmospheric chemistry. This article highlights the evolving science needs for this community and emphasizes how our knowledge is far from complete, hindering our ability to predict the future state of our atmosphere and to respond to emerging global environmental change issues. Laboratory studies provide rich opportunities to expand our understanding of the atmosphere via collaborative research with the modeling and field measurement communities, and with neighboring disciplines.


Assuntos
Mudança Climática , Ozônio/química , Poluição do Ar , Atmosfera/química , Ecossistema , Humanos
15.
J Expo Sci Environ Epidemiol ; 27(6): 601-609, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-27531370

RESUMO

Six males clad only in shorts were exposed to high levels of airborne di(n-butyl) phthalate (DnBP) and diethyl phthalate (DEP) in chamber experiments conducted in 2014. In two 6 h sessions, the subjects were exposed only dermally while breathing clean air from a hood, and both dermally and via inhalation when exposed without a hood. Full urine samples were taken before, during, and for 48 h after leaving the chamber and measured for key DnBP and DEP metabolites. The data clearly demonstrated high levels of DnBP and DEP metabolite excretions while in the chamber and during the first 24 h once leaving the chamber under both conditions. The data for DnBP were used in a modeling exercise linking dose models for inhalation and transdermal permeation with a simple pharmacokinetic model that predicted timing and mass of metabolite excretions. These models were developed and calibrated independent of these experiments. Tests included modeling of the "hood-on" (transdermal penetration only), "hood-off" (both inhalation and transdermal) scenarios, and a derived "inhalation-only" scenario. Results showed that the linked model tended to duplicate the pattern of excretion with regard to timing of peaks, decline of concentrations over time, and the ratio of DnBP metabolites. However, the transdermal model tended to overpredict penetration of DnBP such that predictions of metabolite excretions were between 1.1 and 4.5 times higher than the cumulative excretion of DnBP metabolites over the 54 h of the simulation. A similar overprediction was not seen for the "inhalation-only" simulations. Possible explanations and model refinements for these overpredictions are discussed. In a demonstration of the linked model designed to characterize general population exposures to typical airborne indoor concentrations of DnBP in the United States, it was estimated that up to one-quarter of total exposures could be due to inhalation and dermal uptake.


Assuntos
Poluentes Atmosféricos/urina , Dibutilftalato/urina , Exposição Ambiental/análise , Monitoramento Ambiental/métodos , Poluentes Ambientais/urina , Inalação , Absorção Cutânea , Adulto , Dinamarca , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
16.
Environ Sci Technol ; 51(3): 1140-1146, 2017 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-27997143

RESUMO

Ultrafine particles (UFP) produced by electric heating of stoves and metal cooking pans, absent food, have been hypothesized to be created from a surface film of semivolatile organic compounds (SVOCs) sorbed from the surrounding air. This study tests that hypothesis by size-resolved measurements extending the lower range of the UFP studied from 10 to 2.3 nm, and including other surfaces (glass, aluminum, and porcelain). Heating glass Petri dishes or squares of aluminum foil to about 350-400 °C for 4-6 min removed all sorbed organic substances completely. Subsequent exposure of these "clean" Petri dishes and foil squares to indoor air in two different residences for successively longer periods (1 h to 281 days), followed by heating the materials for 4-6 min, indicated a strong relationship of the number, size distribution, and mass of the UFP to the time exposed. Estimates of the accumulation rate of SVOCs on surfaces were similar to those in studies of organic film buildup on indoor windows. Transfer of skin oils by touching the glass or foil surfaces, or after washing the glass surface with detergent and bare hands, was also observed, with measured particle production comparable with that produced by long-term exposure to indoor air.


Assuntos
Poluição do Ar em Ambientes Fechados , Habitação , Poluentes Atmosféricos , Culinária , Calefação , Compostos Orgânicos , Tamanho da Partícula
17.
Environ Sci Technol ; 50(18): 10236-44, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27571436

RESUMO

This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed.


Assuntos
Poluição do Ar em Ambientes Fechados , Ozônio , Poluentes Atmosféricos , China , Tamanho da Partícula , Eletricidade Estática
18.
Chemosphere ; 154: 559-566, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27085316

RESUMO

Organophosphates are used in a wide range of materials and consumer products and are ubiquitous in indoor environments. Certain organophosphates have been associated with various adverse health effects. The present paper reports mass fractions of organophosphates in dust samples collected from 500 bedrooms and 151 daycare centers of children living in Odense, Denmark. The identified compounds include: tris(isobutyl) phosphate (TIBP), tri-n-butyl phosphate (TNBP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), tris(2-butoxyethyl) phosphate (TBOEP), triphenylphosphate (TPHP), 2-ethylhexyl-diphenyl phosphate (EHDPP), tris(2-ethylhexyl) phosphate (TEHP) and tris(methylphenyl) phosphate (TMPP). Both the number of organophosphates with median values above the limit of detection and the median values were higher for samples from daycare centers than for samples from homes. Organophosphates with median mass fractions above the limit of detection were: TCEP from homes (6.9 µg g(-1)), and TCEP (16 µg g(-1)), TCIPP (5.6 µg g(-1)), TDCIPP (7.1 µg g(-1)), TBOEP (26 µg g(-1)), TPHP (2.0 µg g(-1)) and EHDPP (2.1 µg g(-1)) from daycare centers. When present, TBOEP was typically the most abundant of the identified OPs. The sum of the organophosphate dust mass fractions measured in this study was roughly in the mid-range of summed mass fractions reported for dust samples collected in other countries. On a global scale, the geographical distribution of organophosphates in indoor dust is quite variable, with higher concentrations in industrialized countries. This trend differs from that for phthalate esters, whose geographic distribution is more homogeneous. Exposure to organophosphates via dust ingestion is relatively low, although there is considerable uncertainly in this assessment.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Asma/fisiopatologia , Creches/estatística & dados numéricos , Poeira/análise , Monitoramento Ambiental/estatística & dados numéricos , Ésteres/análise , Organofosfatos/análise , Estudos de Casos e Controles , Criança , Dinamarca , Monitoramento Ambiental/métodos , Retardadores de Chama/análise , Humanos , Instituições Acadêmicas
19.
Environ Sci Technol ; 50(8): 4350-7, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27007912

RESUMO

Clothing can either retard or accelerate dermal exposure to phthalates. To investigate the impact of clothing on dermal exposure to six phthalates (DMP/DEP/DiBP/DnBP/BBzP/DEHP) in real environments, two sets of experiments have been conducted: (1) Skin wipes were collected from 11 adults to examine the phthalate levels on both bare-skin (hand/forehead) and clothing-covered body locations (arm/back/calf); (2) Five adults were asked to wear just-washed jeans for 1 day (1(st) experiment), 5 days (2(nd) experiment), and 10 days (3(rd) experiment). Phthalate levels on their legs were measured on selected days during the wearing period, and phthalate levels in the jeans were measured at the end of each experiment and again after washing. Measured phthalate levels on body locations covered by clothing were lower than those on uncovered locations, but still substantial. Dermal uptake would be underestimated by a factor of 2 to 5 if absorption through body locations covered by clothing were neglected. Phthalate levels in the jeans and on the legs increased with the wearing time. However, the levels in the jeans and on the legs were not strongly correlated, indicating that other pathways, e.g, contact with bedding or bedclothes, likely contribute to the levels on the legs. The efficiency with which laundering washing removed phthalates from the jeans increased with decreasing Kow; median values ranged from very low (<5%) for DEHP to very high (∼75%) for DMP.


Assuntos
Vestuário , Exposição Ambiental/análise , Poluentes Ambientais/análise , Ácidos Ftálicos/análise , Pele/química , Adulto , Feminino , Humanos , Perna (Membro) , Masculino
20.
J Expo Sci Environ Epidemiol ; 26(1): 113-8, 2016 Jan-Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26058800

RESUMO

To assess the influence of clothing on dermal uptake of semi-volatile organic compounds (SVOCs), we measured uptake of selected airborne phthalates for an individual wearing clean clothes or air-exposed clothes and compared these results with dermal uptake for bare-skinned individuals under otherwise identical experimental conditions. Using a breathing hood to isolate dermal from inhalation uptake, we measured urinary metabolites of diethylphthalate (DEP) and di-n-butylphthalate (DnBP) from an individual exposed to known concentrations of these compounds for 6 h in an experimental chamber. The individual wore either clean (fresh) cotton clothes or cotton clothes that had been exposed to the same chamber air concentrations for 9 days. For a 6-h exposure, the net amounts of DEP and DnBP absorbed when wearing fresh clothes were, respectively, 0.017 and 0.007 µg/kg/(µg/m(3)); for exposed clothes the results were 0.178 and 0.261 µg/kg/(µg/m(3)), respectively (values normalized by air concentration and body mass). When compared against the average results for bare-skinned participants, clean clothes were protective, whereas exposed clothes increased dermal uptake for DEP and DnBP by factors of 3.3 and 6.5, respectively. Even for non-occupational environments, wearing clothing that has adsorbed/absorbed indoor air pollutants can increase dermal uptake of SVOCs by substantial amounts relative to bare skin.


Assuntos
Poluentes Atmosféricos/análise , Poluentes Atmosféricos/urina , Poluição do Ar em Ambientes Fechados/análise , Vestuário , Absorção Cutânea , Compostos Orgânicos Voláteis/urina , Dinamarca , Monitoramento Ambiental , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco
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