| 1. |
- Andersen, Christina, et al.
(författare)
-
Inhalation and dermal uptake of particle and gas phase phthalates - A human chamber exposure study
- 2018
-
Ingår i: 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. - 9781713826514
-
Konferensbidrag (refereegranskat)abstract
- We have exposed sixteen test subjects to particle and gas phase phthalates in the controlled chamber exposure study. Deuterium labelled phthalates were used to generate particle D4-DEHP (di(2-ethylhexyl) phthalate) and gas phase D4-DEP (diethyl phthalate) for exposures scenarios allowed studying the dermal only and combined inhalational and dermal uptake. Metabolites were measured in urine samples before and after three hours of exposure. The inhalation was the dominant route of uptake for both DEHP and DEP in this study design and exposure settings. Larger uptake of DEP compared to DEHP both via inhalation and dermal uptake was observed. Dermal uptake of DEHP was not observed in this study. Inhalational urinary excretion factors of the metabolites were found to be 0.73 for DEHP and 0.53 for DEP. This study also highlights the importance of taking into consideration the deposited dose of inhaled particles in studies of uptake of particles.
|
|
| 2. |
- Andersen, Christina, et al.
(författare)
-
Inhalation and Dermal Uptake of Particle and Gas-phase Phthalates - A Human Exposure Study
- 2018
-
Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 52:21, s. 12792-12800
-
Tidskriftsartikel (refereegranskat)abstract
- Phthalates are ubiquitous in indoor environments, which raises concern about their endocrine disrupting properties. However, studies of human uptake from airborne exposure are limited. We studied the inhalation uptake and dermal uptake by air-to-skin transfer with clean clothing as a barrier of two deuterium-labelled airborne phthalates: particle-phase D4-DEHP (di-(2-ethylhexyl)phthalate) and gas-phase D4-DEP (diethyl phthalate). Sixteen participants, wearing trousers and long-sleeved shirts, were under controlled conditions exposed to airborne phthalates in four exposure scenarios: dermal uptake alone, and combined inhalation+dermal uptake of both phthalates. The results showed an average uptake of D4-DEHP by inhalation of 0.0014±0.00088 (µg kg-1 bw)/(µg m-3)/h. No dermal uptake of D4-DEHP was observed during the 3 hour exposure with clean clothing. The deposited dose of D4-DEHP accounted for 26% of the total inhaled D4-DEHP mass. For D4-DEP, the average uptake by inhalation+dermal was 0.0067±0.0045 and 0.00073±0.00051 (µg kg-1 bw)/(µg m-3)/h for dermal uptake. Urinary excretion factors of metabolites after inhalation were estimated to 0.69 for D4-DEHP and 0.50 for D4-DEP. Under the described settings, the main uptake of both phthalates was through inhalation. The results demonstrate the differences in uptake of gas and particles, and highlights the importance of considering the deposited dose in particle uptake studies.
|
|
| 3. |
- Eriksson, Axel Christian, et al.
(författare)
-
Influence of airborne particles' chemical composition on SVOC uptake from PVC flooring - time resolved analysis with aerosol mass spectrometry
- 2020
-
Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; , s. 85-91
-
Tidskriftsartikel (refereegranskat)abstract
- We sampled ammonium sulfate particles and indoor particles of outdoor origin through a small chamber covered with polyvinyl chloride (PVC) flooring. We measured the uptake of semi-volatile organic compounds (SVOC) by the airborne particles in real time. The particles acquired SVOC mass fractions up to 10%. The phthalate ester DEHP (di(2-ethylhexyl)phthalate), a known endocrine disruptor, contributed by approximately half of the sorbed SVOC mass. The indoor particles acquired higher DEHP fraction than laboratory generated ammonium sulfate aerosol. We attribute this increased uptake to absorption by organic matter present in the indoor particles. Using a thermodenuder to remove volatile components, predominantly organics, reduced SVOC uptake. Positive matrix factorization applied to the organic mass spectra suggests that hydrocarbon-like organic aerosol (typically fresh traffic exhaust) sorbs DEHP more efficiently than aged organic aerosol. SVOC uptake is one of the processes that modifies outdoor pollution particles after they penetrate buildings, where the majority of exposure occurs. Particles from indoor sources, typically dominated by organic matter, will undergo such processes as well. Aerosol mass spectrometry improves the time resolution of experimental investigations into these processes, and enables experiments with lower, relevant particle concentrations. Additionally, particle size resolved results are readily obtained.
|
|
| 4. |
|
|
| 5. |
- Eriksson, Axel C., et al.
(författare)
-
The role of organic fraction of aerosol particles in uptake of indoor SVOC investigated with real time aerosol mass spectrometry
- 2018
-
Ingår i: 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. - 9781713826514
-
Konferensbidrag (refereegranskat)abstract
- We investigate the uptake of the Di(2-ethylhexyl) phthalate (DEHP) by laboratory generated and ambient aerosol particles passing through a 1.2 liter chamber covered with vinyl flooring on its internal surfaces. We found approximately five times more efficient DEHP uptake on a mass basis by organic particles (ambient particles) compared to laboratory generated salt particles. The increased uptake is likely due to increased adsorption by pre-existing organic aerosol, which is abundant in the ambient aerosol particles. This implies that compounds with adverse health outcomes are added to particles in indoor air after infiltration into buildings via gas-to-particle conversion of indoor generated SVOCs. We show that aerosol mass spectrometry is a suitable tool for highly time-resolved investigations of this process.
|
|
| 6. |
|
|
| 7. |
- Isaxon, Christina, et al.
(författare)
-
Realistic indoor nano-aerosols for a human exposure facility
- 2013
-
Ingår i: Journal of Aerosol Science. - : Elsevier BV. - 0021-8502. ; 60, s. 55-66
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to achieve realistic levels of two different types of aerosols commonly abundant in indoor environments in an experimental chamber intended for human exposure studies and aerosol characterization. The aerosols chosen were particles from candle lights (in particle number dominated by inorganic water soluble particles) and from ozone-terpene reactions (organic particles). The aerosol generation and characterization system consisted of a controlled air tight stainless steel 22 m(3) chamber, to which the generation set-ups were connected. No air could enter or leave the chamber except through a conditioning system by which temperature, relative humidity and air exchange rate could be controlled. Candle smoke aerosol was generated from ten candles burning in a 1.33 m(3) glass and stainless steel chamber. The aerosol was diluted by clean air from the conditioning system before entering the chamber. Terpene vapor was generated by passing pure nitrogen through a glass bottle containing limonene oil. Ozone was generated by a spark discharge using pure O-2, and was added to the ventilation air flow downstream the inlet for terpene vapors and upstream the inlet to the chamber. Both aerosols were characterized with respect to number and mass concentrations, size distribution and chemical composition. Particle number concentration in the size range 10-650 nm could be varied from <10 cm(-3) to more than 900,000 cm(-3) (for candle smoke) or to more than 30,000 cm(-3) (for particles formed in a 160 ppb terpene/40 ppb ozone mixture). Furthermore, the set-ups were evaluated by, for each source, repeating the generation at six three-hour long events. For both aerosols repeatable generations at pre-determined concentration levels, that were stable over time, could be achieved. The results show that realistic concentrations of aerosols from real-world environments could be reproduced in a well-controlled manner and that this set-up could be used both for aerosol characterization and for human exposures. (C) 2013 Elsevier Ltd. All rights reserved.
|
|
| 8. |
- Krais, Annette M., et al.
(författare)
-
Excretion of Urinary Metabolites of the Phthalate Esters DEP and DEHP in 16 Volunteers after Inhalation and Dermal Exposure
- 2018
-
Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1660-4601. ; 15:11
-
Tidskriftsartikel (refereegranskat)abstract
- Phthalate esters are suspected endocrine disruptors that are found in a wide range of applications. The aim of this study was to determine the excretion of urinary metabolites in 16 individuals after inhalation and/or dermal exposure to 100⁻300 µg/m³ of deuterium-labelled diethyl phthalate (D₄-DEP) and bis(2-ethylhexyl) phthalate (D₄-DEHP). Dermal exposure in this study represents a case with clean clothing acting as a barrier. After inhalation, D₄-DEP and D₄-DEHP metabolites were excreted rapidly, though inter-individual variation was high. D₄-DEP excretion peaked 3.3 h (T½ of 2.1 h) after combined inhalation and dermal exposure, with total excreted metabolite levels ranging from 0.055 to 2.351 nmol/nmol/m³ (nmol of urinary metabolites per phthalates air concentration in (nmol/m³)). After dermal exposure to D₄-DEP, metabolite excretion peaked 4.6 h (T½ of 2.7 h) after exposure, with excreted metabolite levels in between 0.017 and 0.223 nmol/nmol/m³. After combined inhalation and dermal exposure to D₄-DEHP, the excretion of all five analysed metabolites peaked after 4.7 h on average (T½ of 4.8 h), and metabolite levels ranged from 0.072 to 1.105 nmol/nmol/m³ between participants. No dermal uptake of particle phase D₄-DEHP was observed. In conclusion, the average excreted levels of metabolites after combined inhalation and dermal exposure to D₄-DEP was three times higher than after combined exposure to D₄-DEHP; and nine times higher than after dermal exposure of D₄-DEP. This study was made possible due to the use of novel approaches, i.e., the use of labelled phthalate esters to avoid the background concentration, and innovative technique of phthalate generation, both in the particle and the gas phase.
|
|
| 9. |
- Omelekhina, Yuliya, et al.
(författare)
-
Application of positive matrix factorization (PMF) to real time aerosol mass spectrometry measurements in an occupied apartment in Sweden
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction Given that in developed countries we spend about 65% of our time in private homes (Brasche et al. 2005), understanding the exposures in homes is of outmost importance. Airborne particle concentrations indoors can be affected by particles of indoor and outdoor origins, as well as physico-chemical processes indoors, outdoor infiltration affected by tightness of the building envelope and ventilation (Morawska and Salthammer, 2003). In occupied indoor environments, indoor sources may occur simultaneously or as a sequence of the activities. Contribution of airborne particles from different emission sources and various dynamic transformation processes result in 'cocktail effect' in confined indoor spaces. Application of Positive matrix factorization (PMF) source apportionment allows estimating particle contribution from individual sources indoors. The aim of this work was to apply PMF to organic matrix from Aerosol Mass Spectrometer dataset to identify sources contributing to the observed mixture indoors and estimate the relative contributions of organic aerosol types. We present the results of measurements for a three-week period.Methods Indoor and outdoor measurements, using automatic switching valve, were performed in an occupied residence in Malmö, Sweden. Time-of-Flight Aerosol Mass Spectrometer (AMS, DeCarlo et al., 2006) was used to measure non-refractory aerosol mass concentrations indoors and outdoors. Positive matrix factorization (PMF) algorithm was applied to indoor organic aerosol dataset for source identification using the bilinear model through a multilinear engine (ME-2). We used graphical user interface SoFi 6.3 H (Source Finder) (Canonaco et. al, 2013) for source apportionment.Conclusions Positive matrix factorization source apportionment of the organic aerosol matrix identified three primary factors and one secondary factor: cooking OAI (COAI), cooking OAII (COAII), electronic cigarette OA (EOA), oxygenated outdoor OA (OOA) factors using PMF unconstrained runs. The electronic cigarette was the dominant contributor (51%) to indoor concentrations and resulted in average particle mass concentrations of 5.08 μg m-3. Cooking were frequent events in the studied apartment (n=29). On the basic of the activity logbooks 10 activities were identified as cooking, 6 as baking, 12 as frying, and 1 as deep frying. Cooking activities contributed with average mass concentrations of 3.7 μg m-3 (37 %). Two cooking factors, COAI and COAII, were retrieved during PMF analysis. Both COA factor profiles had characteristic peaks at m/z’s 41, 43, 55, 57, 60, 73 similar to results in previous studies (Allan et al., 2010; Crippa et al., 2013). However, the intensity of m/z’s 60 and 73 of COAI was less pronounced compared to COAII, which can be explained by the presence of degraded sugars during cooking (Barham, 1950). Oxygenated outdoor OA (OOA) factor reflected penetration of oxygenated organic species and was the least pronounced (1.2 μg m-3, 12 %) source indoors. OA mass spectrum was dominated by the CO2+ ion, and formed as a result of decomposition of oxygenated organic acids, as reported earlier by Ng et al. 2010. PMF also enabled identification of unknown sources such as electronic cigarette (by tracing glycerine peak at m/z 61) and some cooking activities.PMF source apportionment has shown to be useful tool for separation and identification of contributing sources indoors. However, PMF was ineffective for identification of candle burning. Due to similarity of COAI and candle burning mass spectrum, it was decided to proceed with PMF analysis without candle burning profile. Indoor sources, such as vaping of the electronic cigarette and cooking activities were the main contributors of organic submicrometer-size range particles in studied apartment during the three week measurement period. Thus, these should not be neglected when considering possible health effects. This work was financed by the Swedish Research Council FORMAS (Project Dnr 942-2015-1029) and COST Action, CA 16109.
|
|
| 10. |
- Omelekhina, Yuliya, et al.
(författare)
-
Chemical composition of airborne particles inside and outside a Swedish residence assessed by real time aerosol mass spectrometry
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A number of deleterious health effects have been identified from exposure to outdoor air-borne particulate matter. This issue is complicated by the fact that people are spending most of the time indoors, where particles of both indoor and outdoor origin are present. The aim of this work was to assess the differences in particle chemical composition inside and outside of the residence and gain better understanding about major contributors to the observed levels indoors. Our results showed that indoor aerosol mass concentration exceeded the outdoor values mainly due to the contribution of organic matter from indoor sources during the presence of the residents at home. The infiltration of chemical species from outdoors was not the major factor determining indoor aerosol mass concentration and chemical composition.1 INTRODUCTIONConsidering that on average in developed countries we spend about 65% (Brashe and Bis-chof) of our time in private homes, the understanding of exposure to particulate matter in homes is important, yet knowledge is sparse. Indoors, aerosol concentrations come from in-door sources, infiltrate from outdoors and can be formed through reactions of gas-phase precursors emitted both indoors and outdoors. Several characteristics and processes influence the properties of aerosols indoors, among them: active indoor sources (presence of occupants), outdoor aerosol characteristics, physicochemical particle transformations during infiltration and while indoors, ventilation type, tightness of the building envelope and particle deposition (Morawska et al., 2013). In this study, we aimed to investigate the differences in chemical composition between aerosols inside and outside of the residence and to identify the origin of major contributors to the particle levels indoors. We report preliminary results of measure-ments for a 1-month period in an occupied apartment. 2 METHODS Indoor and outdoor measurements were performed in an occupied residence in Malmö, Swe-den. It was a naturally ventilated four-room apartment (292 m3), located in a three-store con-crete building surrounded by a green zone. A Time-of-Flight Aerosol Mass Spectrometer (AMS, DeCarlo et al., 2006) was used to measure particle mass loadings and size-resolved mass distributions (size range of 50-500 nm) of indoor and outdoor organic, sulphate, nitrate, ammonium and chloride aerosols. An automatic switching valve alternated between indoor and outdoor lines with a time interval of 20 and 10 minutes in indoor and outdoor air, respectively. Both sampling lines were mounted at the ground floor level and led to the basement where the aerosol was dried and measured by AMS. Calculated residence time of the particles in line was 1.5 minutes. Indoor sampling line was heated and insulated, additional carrier flow was used to lower the resi-dence time. Indoor to outdoor (I/O) ratios were calculated and used for comparisons of differences in aerosol composition inside and outside of the residence.3 RESULTS AND DISCUSSIONThe results showed higher total average mass concentration indoors (12.9 μg/m3) compared to outdoors (5.4 μg/m3) during entire measuring period. Indoor to outdoor (I/O) ratio for or-ganics was 6.7, for nitrate 0.3, for sulphate 0.5, for ammonium 0.2 and for chloride 0.2. Or-ganic matter was the dominant species indoors, accounting for most of the total mass (92 %) due to contribution from indoor sources during the time when residents were at home, i.e. occupancy period. Figure 1A illustrates elevated particle mass concentrations when different indoor activities took place. Effects of penetration and phase change of the outdoor particle species can be observed during non-occupancy period (Figure 1B). Non-occupancy time ac-counted only to 7 % of the total monitoring period and did not have much influence on parti-cle mass concentration indoors.Ammonium nitrate (NH4NO3) and ammonium chlorine (NH4Cl) are semi-volatile aerosol species, thus, gas-to-particle partitioning depends on temperature, relative humidity, particle size and gas phase concentrations of ammonia, nitric acid and chlorine as outdoor air is transported indoors (Mozurkewich, 1993; Lunden et al., 2004). Such phase transitions are especially pronounced in the cold period of the year. The outdoor weather conditions varied during this time with Tout from -8.8 to 9.7 °C and RHout from 58 to 100 %. Indoors, Tin ranged from 20 to 26.1 °C and RHin from 27 to 50 %. Low value of I/O ratio for non-volatile sul-phate can be explained by dominating of the outdoor sources and reflects reduced infiltra-tion. The outdoor total mass concentration in urban sites measured by TOF-AMS was comparable with previous studies (Crippa et al., 2014; Jimenez et al., 2009). Some local sources, such as emissions from fireplaces by neighbours and from adjacent fast food restaurants could have contributed to the outdoor loadings. 4 CONCLUSIONSIn general, the differences in chemical composition of particles found indoors and outdoors becomes apparent from the results. Levels of organics in indoor environments were mainly influenced by indoor sources, thus, these should not be neglected when considering possible health effects. Additionally, reduced air exchange rate in the apartment in Scandinavia during wintertime enhanced aerosol accumulation and physicochemical transformation indoors.ACKNOWLEDGEMENTThis work was financed by the Swedish Research Council FORMAS (Project Dnr 942-2015-1029).
|
|
