共查询到20条相似文献，搜索用时 0 毫秒
1.
Christina Andersen Yuliya Omelekhina Berit Brøndum Rasmussen Mette Nygaard Bennekov Søren Nielsen Skov Morten Køcks Kai Wang Bo Strandberg Fredrik Mattsson Merete Bilde Marianne Glasius Joakim Pagels Aneta Wierzbicka 《Indoor air》2021,31(6):2033-2048
Burning candles release a variety of pollutants to indoor air, some of which are of concern for human health. We studied emissions of particles and gases from the stressed burning of five types of pillar candles with different wax and wick compositions. The stressed burning was introduced by controlled fluctuating air velocities in a 21.6 m3 laboratory chamber. The aerosol physicochemical properties were measured both in well-mixed chamber air and directly above the candle flame with online and offline techniques. All candles showed different emission profiles over time with high repeatability among replicates. The particle mass emissions from stressed burning for all candle types were dominated by soot (black carbon; BC). The wax and wick composition strongly influenced emissions of BC, PM2.5, and particle-phase polycyclic aromatic hydrocarbons (PAHs), and to lower degree ultrafine particles, inorganic and organic carbon fraction of PM, but did not influence NOx, formaldehyde, and gas-phase PAHs. Measurements directly above the flame showed empirical evidence of short-lived strong emission peaks of soot particles. The results show the importance of including the entire burn time of candles in exposure assessments, as their emissions can vary strongly over time. Preventing stressed burning of candles can reduce exposure to pollutants in indoor air. 相似文献
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Berit B. Rasmussen Kai Wang Johan G. Karstoft Søren N. Skov Morten Køcks Christina Andersen Aneta Wierzbicka Joakim Pagels Peter B. Pedersen Marianne Glasius Merete Bilde 《Indoor air》2021,31(4):1084-1094
Emissions from candles are of concern for indoor air quality. In this work, five different types of pillar candles were burned under steady burn conditions in a new laboratory scale system for repeatable and controlled comparison of candle emissions (temperature ~25°C, relative humidity ~13%, O2 >18%, air exchange rate 1.9 h−1). Burn rate, particle number concentrations, mass concentrations, and mode diameters varied between candle types. Based on the results, the burning period was divided in two phases: initial (0–1 h) and stable (1–6 h). Burn rates were in the range 4.4–7.3 and 4.7–7.1 g/h during initial and stable phase, respectively. Relative particle number emissions, mode diameters, and mass concentrations were higher during the initial phase compared to the stable phase for a majority of the candles. We hypothesize that this is due to elevated emissions of wick additives upon ignition of the candle together with a slightly higher burn rate in the initial phase. Experiments at higher relative humidity (~40%) gave similar results with a tendency toward larger particle sizes at the higher relative humidity. Chemical composition with respect to inorganic salts was similar in the emitted particles (dry conditions) compared to the candlewicks, but with variations between different candles. 相似文献
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This study aimed to measure in French children personal exposure concentrations of black carbon (BC) and ultrafine particles (UFP) and to quantify the contribution of different microenvironments (home, school, places of extracurricular activities, transport) to their total exposure. It was conducted on 96 9‐year‐old children from the PARIS birth cohort. BC and UFP were continuously measured by portable devices (microAeth® AE51 and DiSCmini®) for a minimum of 24 hours, while participating families simultaneously filled in a space‐time‐activities‐budget questionnaire. BC exposure concentration was higher during trips (principally metro/train and bus), while UFP exposure concentration was higher during indoor activities (mainly eating at restaurants) and in trips. The most important UFP peaks were measured at home, especially during cooking. Home and school together accounted for much of the total exposure, 83.8% for BC and 85.3% for UFP. The contribution of transport to total exposure was 12.4% for BC and 9.7% for UFP, while extracurricular activities were responsible for 3.8% and 5% of the total exposure to BC and UFP, respectively. 相似文献
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P. Pañella M. Casas D. Donaire‐Gonzalez R. Garcia‐Esteban O. Robinson A. Valentín J. Gulliver I. Momas M. Nieuwenhuijsen M. Vrijheid J. Sunyer 《Indoor air》2017,27(5):891-899
Traffic‐related air pollution (TRAP) exposure during childhood is associated with asthma; however, the contribution of the different TRAP pollutants in each microenvironment (home, school, transportation, others) in asthmatic and non‐asthmatic children is unknown. Daily (24‐h) personal black carbon (BC), ultrafine particle (UFP), and alveolar lung‐deposited surface area (LDSA) individual exposure measurements were obtained from 100 children (29 past and 21 current asthmatics, 50 non‐asthmatics) aged 9±0.7 years from the INMA‐Sabadell cohort (Catalonia, Spain). Time spent in each microenvironment was derived by the geolocation provided by the smartphone and a new spatiotemporal map‐matching algorithm. Asthmatics and non‐asthmatics spent the same amount of time at home (60% and 61%, respectively), at school (20% and 23%), on transportation (8% and 7%), and in other microenvironments (7% and 5%). The highest concentrations of all TRAPs were attributed to transportation. No differences in TRAP concentrations were found overall or by type of microenvironment between asthmatics and non‐asthmatics, nor when considering past and current asthmatics, separately. In conclusion, asthmatic and non‐asthmatic children had a similar time‐activity pattern and similar average exposures to BC, UFP, and LDSA concentrations. This suggests that interventions should be tailored to general population, rather than to subgroups defined by disease. 相似文献
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Melissa Hachem Lynda Bensefa-Colas Nathalie Lahoud Marwan Akel Isabelle Momas Nadine Saleh 《Indoor air》2020,30(6):1308-1316
Taxi drivers’ exposure to traffic-related air pollutants inside their vehicles has been reported in different countries but not yet in Lebanon. Thus, we conducted a cross-sectional study on 20 Lebanese taxi drivers to (1) assess their exposure to ultrafine particles (UFP) and black carbon (BC) inside their vehicles and (2) identify determinants of this exposure. UFP and BC were measured using Diffusion Size Classifier Miniature® and microAeth ® Model AE51, respectively, for 5 hours. Data on characteristics of vehicles and trips were collected by face-to-face interviews. Associations between pollutant levels and their determinants were analyzed by multiple linear regression. The mean of UFP count (35.2 ± 17.6 x 103 particles cm-3) and BC (5.2 ± 1.9 μg m-3) concentrations in-taxis was higher in the morning measurements compared with those in the afternoon measurements. UFP count increased in-taxis by 60% for every 10 minutes spent in blocked traffic and by 84% starting from two trips with smokers compared to trips without smokers. Conversely, UFP count decreased by 30% for every 10 minutes under both air-conditioning and air recirculation mode with windows closed. BC was not affected by any of these factors. Our findings suggest easy ways to reduce UFP exposure inside vehicles for all commuters. 相似文献
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This study presents real-time concentrations of traffic-related air pollutants during 499 trips conducted by 50 Parisian taxi drivers from PUF-TAXI project. Ultrafine particles (UFP), black carbon (BC), and nitrogen dioxide (NO2)/carbon monoxide (CO) were measured inside vehicles by Diffusion Size Classifier Miniature®, microAeth®, and Gas-Pro®, respectively, for nine hours. Vehicle/trip data characteristics were collected by questionnaires and on ambient conditions by monitoring stations. The associations between pollutant levels and their potential determinants were analyzed using generalized estimating equation model. Determinants of in-vehicle pollutants levels were identified: (1) ambient factors (meteorology and ambient pollution)—affecting BC, NO2, and CO; (2) vehicle characteristics—affecting all pollutants; and (3) trip-related driving habits—affecting UFP, BC, and CO. We highlight that commuters can, therefore, avoid high in-vehicle air pollutant concentrations mainly by (1) closing windows and activating air-conditioning under air recirculation mode in congested traffic; (2) smooth driving; and (3) maintaining cabin air filters. 相似文献
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Taina Siponen Tarja Yli‐Tuomi Pekka Tiittanen Pekka Taimisto Juha Pekkanen Raimo O. Salonen Timo Lanki 《Indoor air》2019,29(3):413-422
A six‐month winter‐spring study was conducted in a suburb of the northern European city of Kuopio, Finland, to identify and quantify factors determining daily personal exposure and home indoor levels of fine particulate matter (PM2.5, diameter <2.5 µm) and its light absorption coefficient (PM2.5abs), a proxy for combustion‐derived black carbon. Moreover, determinants of home indoor ozone (O3) concentration were examined. Local central site outdoor, home indoor, and personal daily levels of pollutants were monitored in this suburb among 37 elderly residents. Outdoor concentrations of the pollutants were significant determinants of their levels in home indoor air and personal exposures. Natural ventilation in the detached and row houses increased personal exposure to PM2.5, but not to PM2.5abs, when compared with mechanical ventilation. Only cooking out of the recorded household activities increased indoor PM2.5. The use of a wood stove room heater or wood‐fired sauna stove was associated with elevated concentrations of personal PM2.5 and PM2.5abs, and indoor PM2.5abs. Candle burning increased daily indoor and personal PM2.5abs, and it was also a determinant of indoor ozone level. In conclusion, relatively short‐lasting wood and candle burning of a few hours increased residents’ daily exposure to potentially hazardous, combustion‐derived carbonaceous particulate matter. 相似文献
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This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I‐80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir‐fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year‐round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM2.5 by 97‐98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor‐generated particles. Systems with MERV13‐16 filter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93‐98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5. Indoor ozone was 3‐4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25‐75% when operated over the hour following cooking. The energy for year‐round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year. 相似文献
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Luca Stabile Gianmarco De Luca Antonio Pacitto Lidia Morawska Pasquale Avino Giorgio Buonanno 《Indoor air》2021,31(1):63-73
The new particle formation due to the use of cleaning products containing volatile organic compounds (VOCs) in indoor environments is well documented in the scientific literature. Indeed, the physical-chemical process occurring in particle nucleation due to VOC-ozone reactions was deepened as well as the effect of the main influencing parameters (ie, temperature, ozone). Nonetheless, proper quantification of the emission under actual meteo-climatic conditions and ozone concentrations is not available. To this end, in the present paper the emission factors of newly generated ultrafine particles due to the use of different floor cleaning products under actual temperature and relative humidity conditions and ozone concentrations typical of the summer periods were evaluated. Tests in a chamber and in an actual indoor environment were performed measuring continuously particle number concentrations and size distributions during cleaning activities. The tests revealed that a significant particle emission in the nucleation mode was present for half of the products under investigation with emission factors up to 1.1 × 1011 part./m2 (8.8 × 1010 part./mLproduct), then leading to an overall particle emission comparable to other well-known indoor sources when cleaning wide surfaces. 相似文献
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The aim of this work was to assess ultrafine particles (UFP) number concentrations in different microenvironments of Portuguese preschools and to estimate the respective exposure doses of UFP for 3–5‐year‐old children (in comparison with adults). UFP were sampled both indoors and outdoors in two urban (US1, US2) and one rural (RS1) preschool located in north of Portugal for 31 days. Total levels of indoor UFP were significantly higher at the urban preschools (mean of 1.82 × 104 and 1.32 × 104 particles/cm3 at US1 an US2, respectively) than at the rural one (1.15 × 104 particles/cm3). Canteens were the indoor microenvironment with the highest UFP (mean of 5.17 × 104, 3.28 × 104, and 4.09 × 104 particles/cm3 at US1, US2, and RS1), whereas the lowest concentrations were observed in classrooms (9.31 × 103, 11.3 × 103, and 7.14 × 103 particles/cm3 at US1, US2, and RS1). Mean indoor/outdoor ratios (I/O) of UFP at three preschools were lower than 1 (0.54–0.93), indicating that outdoor emissions significantly contributed to UFP indoors. Significant correlations were obtained between temperature, wind speed, relative humidity, solar radiation, and ambient UFP number concentrations. The estimated exposure doses were higher in children attending urban preschools; 3–5‐year‐old children were exposed to 4–6 times higher UFP doses than adults with similar daily schedules. 相似文献
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Airborne ultrafine particles (UFP) have been related to adverse health effects, but exposure in vulnerable population groups such as children is still not well understood. We aim to review the scientific literature regarding personal exposure to UFP in different microenvironments in populations until 18 years of age. The bibliographical search was carried out in July 2019 using the online database PubMed and was completed with references in articles found in the search. We selected the studies that used continuous counters and measured UFP levels in both specific microenvironment (houses, schools, transport, etc) and personal exposure. Finally, 32 studies fulfilled the criteria: of these, 10 analyzed personal exposure and 22 examined UFP levels in the microenvironment (especially in schools or nurseries (18/22)) and five in various microenvironments (including dwellings and means of transport, where exposure levels were higher). The characteristics of the microenvironments with the greatest levels of UFP were being close to heavy traffic or near cooking and cleaning activities. This review revealed the wide differences in exposure assessment methodologies that could lead to a lack of uniform and comparable information about the real UFP exposure in children. 相似文献
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S. Karrasch M. Simon B. Herbig J. Langner S. Seeger A. Kronseder S. Peters G. Dietrich‐Gümperlein R. Schierl D. Nowak R. A. Jörres 《Indoor air》2017,27(4):753-765
Ultrafine particles emitted from laser printers are suspected to elicit adverse health effects. We performed 75‐minute exposures to emissions of laser printing devices (LPDs) in a standardized, randomized, cross‐over manner in 23 healthy subjects, 14 mild, stable asthmatics, and 15 persons reporting symptoms associated with LPD emissions. Low‐level exposures (LLE) ranged at the particle background (3000 cm?3) and high‐level exposures (HLE) at 100 000 cm?3. Examinations before and after exposures included spirometry, body plethysmography, transfer factors for CO and NO (TLCO, TLNO), bronchial and alveolar NO, cytokines in serum and nasal secretions (IL‐1β, IL‐5, IL‐6, IL‐8, GM‐CSF, IFNγ, TNFα), serum ECP, and IgE. Across all participants, no statistically significant changes occurred for lung mechanics and NO. There was a decrease in volume‐related TLNO that was more pronounced in HLE, but the difference to LLE was not significant. ECP and IgE increased in the same way after exposures. Nasal IL‐6 showed a higher increase after LLE. There was no coherent pattern regarding the responses in the participant subgroups or single sets of variables. In conclusion, the experimental acute responses to short but very high‐level LPD exposures were small and did not indicate clinically relevant effects compared to low particle number concentrations. 相似文献
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The ability to inexpensively monitor PM2.5 to identify sources and enable controls would advance residential indoor air quality (IAQ) management. Consumer IAQ monitors incorporating low‐cost optical particle sensors and connections with smart home platforms could provide this service if they reliably detect PM2.5 in homes. In this study, particles from typical residential sources were generated in a 120 m3 laboratory and time‐concentration profiles were measured with 7 consumer monitors (2‐3 units each), 2 research monitors (Thermo pDR‐1500, MetOne BT‐645), a Grimm Mini Wide‐Range Aerosol Spectrometer (GRM), and a Tapered Element Oscillating Microbalance with Filter Dynamic Measurement System (FDMS), a Federal Equivalent Method for PM2.5. Sources included recreational combustion (candles, cigarettes, incense), cooking activities, an unfiltered ultrasonic humidifier, and dust. FDMS measurements, filter samples, and known densities were used to adjust the GRM to obtain time‐resolved mass concentrations. Data from the research monitors and 4 of the consumer monitors—AirBeam, AirVisual, Foobot, Purple Air—were time correlated and within a factor of 2 of the estimated mass concentrations for most sources. All 7 of the consumer and both research monitors substantially under‐reported or missed events for which the emitted mass was comprised of particles smaller than 0.3 μm diameter. 相似文献
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通过实验和理论研究，探讨了谢尔炉炭黑填充ＰＶＣ管材抗静电的机理及其影响因素，为其应用提供了重要依据。 相似文献
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研究了炭黑碳纤维复相导电混凝土的导电性能,分析了导电混凝土的电阻率变化,为实际应用于道路融雪化冰提供理论依据与试验依据。利用纳米导电炭黑和碳纤维作为导电相来改善混凝土的导电性能,进行炭黑碳纤维复相导电混凝土的导电性能试验,分析环境温度、干湿度和外加电压对炭黑碳纤维导电混凝土电阻率的影响。导电混凝土的电阻率受温度、湿度和外加电压的影响,当环境条件发生变化时,导电混凝土的导电性能也会发生变化。炭黑碳纤维复相导电混凝土的电阻率随着温度的升高出现一定程度的减小;干燥状态下的电阻率高于潮湿状态下的电阻率;电阻率随着外加电压的增大有一定程度的减小,当电压达到一定数值时,电阻率趋于稳定。 相似文献