| 1. |
- Andersen, Christina, et al.
(författare)
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Emissions of soot, PAHs, ultrafine particles, NOx, and other health relevant compounds from stressed burning of candles in indoor air
- 2021
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 31:6, s. 2033-2048
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
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| 3. |
- Omelekhina, Yuliya, et al.
(författare)
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Application of positive matrix factorization (PMF) to real time aerosol mass spectrometry measurements in an occupied apartment in Sweden
- 2019
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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.
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| 4. |
- Omelekhina, Yuliya, et al.
(författare)
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Chemical composition of airborne particles inside and outside a Swedish residence assessed by real time aerosol mass spectrometry
- 2018
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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).
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| 5. |
- Omelekhina, Yuliya, et al.
(författare)
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Chemically-resolved particle mass composition in a Swedish residence assessed by a Time-of-Flight Aerosol Mass Spectrometer
- 2018
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Ingår i: ; , s. 1-2
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A number of deleterious health effects have been identified from exposure to outdoor airborne particulate matter. Given that in developed countries we spend majority of our time indoors, in private homes about 65 % (Brashe et al., 2005), the understanding of this exposure is important, yet knowledge is sparse. Particle levels indoors are affected by indoor sources, infiltration from outdoors or particle mass forms through reactions of gas-phase precursors emitted both indoors and outdoors (Morawska et al., 2013). The aim of this work was to characterize a chemical composition of particle mass indoors, and to gain a better understanding about major contributors to the observed indoor levels with Aerosol Mass Spectrometer. We aimed to identify mass spectral signatures of specific indoor sources. This is preliminary results of measurements for a 1-month period.Indoor and outdoor measurements were performed in an occupied residence in Malmö, Sweden. It was a naturally ventilated four-room apartment (292 m3), located in a three-store concrete building surrounded by a green zone. A Time-of-Flight Aerosol Mass Spectrometer (DeCarlo et al., 2006) was used to measure particle mass loadings and size-resolved mass distributions (50-500 nm) of indoor and outdoor chemical species. An automatic switching valve alternated between indoor and outdoor lines with a time interval of 20 and 10 minutes, respectively. Both sampling lines were mounted at the ground floor level and led to the basement where the aerosols were dried and measured by AMS. Our results showed higher total average mass concentration indoors (12.9 μg/m3) compared to outdoors (5.4 μg/m3) over the entire measuring period. Indoor to outdoor (I/O) ratio for organics was 6.7, for sulphate 0.5, for nitrate 0.3, for ammonium 0.2 and for chloride 0.2. The dominant species indoors was organic matter, accounting for most of the total particle mass (92 %) due to contribution from indoor sources and from outdoor infiltration. Non-volatile sulphate showed reduced infiltration from outdoors. From comparison of outdoor and indoor concentrations of ammonium nitrate and ammonium chloride, which are sensitive to temperature and RH (Lunden et al., 2004), a clear reduction due to phase change was observed upon outdoor-to-indoor transport. We investigated different organic mass spectra for indoor events as recorded in the logbooks. The main events analysed comprised from various types of cooking and candle burning. They showed to emit different proportions of hydrocarbons and oxygenated organic species, which yield CxHy+, CxHyO+, CxHyOz+ ion classes. The relative intensity of CxHy+ ion class out of the total organic signal during frying was 65-68 %, deep-frying ~ 68 %, baking 60-70 %, other forms of cooking 60-68 %, candle burning 60-70%. For CxHyO+ ion class: frying 25-30 %, deep-frying 24-25 %, baking 27-32 %, cooking 25-31 %, candle burning 20-30 %. For CxHyOz+ ion family: frying 7-8%, deep-frying 7-8 %, cooking and baking 6-9 %, candle burning 6-8 %. The observed variability in organic mass spectral signature for different indoor sources should allow us to apply Positive Matrix Factorization for source apportionment and processes occurring in indoor air. This will help us to gain a better understanding about main contributors to the observed loading indoors.
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| 6. |
- Omelekhina, Yuliya, et al.
(författare)
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Cooking and electronic cigarettes leading to large differences between indoor and outdoor particle composition and concentration measured by aerosol mass spectrometry
- 2020
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Ingår i: Environmental Sciences: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7895 .- 2050-7887. ; 22:6, s. 1382-1396
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Tidskriftsartikel (refereegranskat)abstract
- We spend about two thirds of our time in private homes where airborne particles of indoor and outdoor origins are present. The negative health effects of exposure to outdoor particles are known. The characteristics of indoor airborne particles, though, are not well understood. This study assesses the differences in chemical composition of PM1 (<1 μm) inside and outside of an occupied Swedish residence in real time with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aethalometer. The chemical composition and concentration of particles indoors showed large differences compared to outdoors. The average indoor concentration was 15 μg m-3 and was higher than the outdoor 7 μg m-3. Organics dominated indoor particle composition (86% of the total mass) and originated from indoor sources (cooking, e-cigarette vaping). The average indoor to outdoor ratios were 5.5 for organic matter, 1.0 for black carbon, 0.6 for sulphate, 0.1 for nitrate, 0.2 for ammonium and 0.2 for chloride. The occupancy time accounted for 97% of the total measured period. Four factors were identified in the source apportionment of organic particle fraction by applying positive matrix factorization (PMF): two cooking factors, one e-cigarette factor and one outdoor contribution (OOA) organic factor penetrated from outside.
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| 7. |
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| 8. |
- Omelekhina, Yuliya, et al.
(författare)
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Effect of energy renovation and occupants' activities on airborne particle concentrations in Swedish rental apartments
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 806
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to airborne particles causes detrimental health effects, hence their assessment in indoor environments, where people spend most of the time, is important. The influence of energy renovation and occupants' activities on airborne particle concentrations was assessed in seven occupied Swedish residences. Ultrafine particle (UFP, <100 nm) number concentrations, PM2.5 (<2.5 μm) and black carbon (BC, <900 nm) mass concentrations were simultaneously measured inside and outside before, after renovation, and during follow-up. The average indoor UFP number concentrations increased from 6200 (±4070) cm-3 before renovation to 12,700 (±6040) cm-3 during the follow up, as the number of indoor activities doubled. Indoor UFP number concentrations depended mainly on frequency and type of occupants' activities in studied residences (e.g., cooking, candle burning). The average indoor PM2.5 concentration decreased from 8.6 (±5.8) μg m-3 before renovation to 2.5 (±1.3) μg m-3 during follow up, as the activities that generated PM2.5 decreased, and infiltration of outdoor particles could have been decreased due to renovation measures. However, the indication of infiltration decrease during the follow up, assessed on the basis of indoor to outdoor ratios during non-activity times (with no influence of occupants' activities), was not observed after the renovation and should be treated with caution. In this study indoor PM2.5 and BC were influenced by activities and outdoor concentrations. Reduction of exposure to indoor UFP, might be obtained by optimization of kitchen exhaust flows. An improved design of supply air inlets in mechanical exhaust ventilation systems may reduce PM2.5 infiltration. Occupants' logbook records, needed for identification of sources contributing to particle exposure, proved useful but not always accurate compared to technical measurements of activities and UFP concentrations. Development of simple and reliable activity detection systems is needed to complement logbooks and allow accurate assessment of source contribution to particle exposure in homes and associated health effects.
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| 9. |
- Omelekhina, Yuliya, et al.
(författare)
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Indoor to outdoor ratio of particle chemical components in an occupied residence
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- IntroductionConsidering that on average in developed countries we spend about 65% of our time in private homes, understanding the exposures in homes is of outmost importance. Aerosol concentrations indoors come from indoor sources, infiltrate from outdoors and can be formed from precursors both of indoor and outdoor origin. Several characteristics and processes influence the properties of aerosols indoors, among them: active indoor sources (presence of occupants), outdoor aerosol characteristics, change of chemical composition upon infiltration (from outdoors to indoors), size dependant penetration from outdoors, ventilation, tightness of the building envelope and deposition (Morawska, et.al. 2013). In this study, we aimed to investigate the differences in chemical composition between aerosols indoors and outdoors. We report preliminary results for 6-days period, with the full duration of the campaign of 1 month.MethodsMeasurements were conducted indoors and outdoors in an occupied residence in Malmo, Sweden. The apartment was naturally ventilated, had four bedrooms and a total area of 117 m2. It was located in a three-store concrete building and enclosed from other areas by green zone. Time-of-Flight Aerosol Mass Spectrometer (AMS, DeCarlo, et al. 2006) was used to measure mass loadings and size-resolved mass distributions of indoor and outdoor organic, sulphate and nitrate particles. Two parallel sampling lines (indoor and outdoor) with automatically switching valve were used. The valve alternated the measurements between indoor and outdoor for 20 and 10 minutes, respectively. Both sampling lines were led to the basement where the aerosol was dried and measured by AMS. Calculated residence time of the particles in line was about 1.5 minutes. Indoor sampling line was heated and insulated, additional carrier flow was used to lower the residence time and ensure the same temperature. ConclusionsCalculated mean indoor/outdoor (I/O) ratios were 3.4 for organics, 0.1 for nitrate, 0.5 for sulphate, 0.2 for ammonium. High I/O ratio for organics was due to high contribution from indoor sources. Indoor activities/sources that contributed to high organics loadings inside comprised of cooking, using of the oven, and candle burning. The nitrate I/O ratio was the lowest because of its evaporation indoors i.e. dissociation of ammonium nitrate particles into gases (nitric acid and ammonia) due to higher temperature and lower relative humidity compared to outdoors. The differences between the indoor and outdoor temperature and RH during the measurements time: outdoor temperatures varied from -1.5 to 7.1 °C and RH from 72 to 100 %; indoors, T ranged from 20 to 26 °C with RH from 27 to 50 %. Low value I/O ratio for non-volatile sulphate can be explained by dominating outdoor sources and reflects reduced infiltration. As can be seen from the Figure 1, during non-occupancy period, mass concentration of organics was very low - a few µg/m3, while with the presence of indoor activities led to organics loadings up to 1 mg/m3. In general, the results confirm differences in chemical composition of particles found indoors and outdoors. Levels of organics in indoor environments was mainly influenced by indoor sources, thus theses should not be neglected when considering possible health effects. This work was financed by the Swedish Research Council FORMAS (Project Dnr 942-2015-1029)
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| 10. |
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