| 1. |
- Aas, Wenche, et al.
(författare)
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Trends in Air Pollution in Europe, 2000–2019
- 2024
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Ingår i: Aerosol and Air Quality Research. - 2071-1409 .- 1680-8584. ; 24:4
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Tidskriftsartikel (refereegranskat)abstract
- This paper encompasses an assessment of air pollution trends in rural environments in Europe over the 2000–2019 period, benefiting from extensive long-term observational data from the EMEP monitoring network and EMEP MSC-W model computations. The trends in pollutant concentrations align with the decreasing emission patterns observed throughout Europe. Annual average concentrations of sulfur dioxide, particulate sulfate, and sulfur wet deposition have shown consistent declines of 3–4% annually since 2000. Similarly, oxidized nitrogen species have markedly decreased across Europe, with an annual reduction of 1.5–2% in nitrogen dioxide concentrations, total nitrate in the air, and oxidized nitrogen deposition. Notably, emission reductions and model predictions appear to slightly surpass the observed declines in sulfur and oxidized nitrogen, indicating a potential overestimation of reported emission reductions. Ammonia emissions have decreased less compared to other pollutants since 2000. Significant reductions in particulate ammonium have however, been achieved due to the impact of reductions in SOx and NOx emissions. For ground level ozone, both the observed and modelled peak levels in summer show declining trends, although the observed decline is smaller than modelled. There have been substantial annual reductions of 1.8% and 2.4% in the concentrations of PM10 and PM2.5, respectively. Elemental carbon has seen a reduction of approximately 4.5% per year since 2000. A similar reduction for organic carbon is only seen in winter when primary anthropogenic sources dominate. The observed improvements in European air quality emphasize the importance of comprehensive legislations to mitigate emissions.
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| 2. |
- Abbasi, Saeed, 1973-, et al.
(författare)
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Technical note: Experiences of studying airborne wear particles from road and rail transport
- 2013
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 13:4, s. 1161-1169
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Tidskriftsartikel (refereegranskat)abstract
- Airborne particles and their adverse effects on air quality have been recognized by humans since ancient times. Current exhaust emission legislations increase the relative contribution of wear particles on the PM levels. Consequently, wearbased particle emissions from rail and road transport have raised concerns as ground transportation is developing quickly. Although scientific research on airborne wear-based particles started in 1909, there is almost no legislation that control the generation of wear-based particles. In addition, there is no accepted and approved standard measurement technique for monitoring and recording particle characteristics. The main objective of this study is to review recent experimental work in this field and to discuss their set-ups, the sampling methods, the results, and their limitations, and to propose measures for reducing these limitations.
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| 3. |
- Cha, Yingying, 1989-, et al.
(författare)
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Variation in Airborne Particulate Levels at a Newly Opened Underground Railway Station
- 2019
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Ingår i: Aerosol and Air Quality Research. - : TAIWAN ASSOC AEROSOL RES-TAAR. - 1680-8584 .- 2071-1409. ; 19:4, s. 737-748
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Tidskriftsartikel (refereegranskat)abstract
- The construction of a new railway tunnel for commuter trains in Stockholm was completed in 2017. It included two modern stations (Odenplan and Stockholm City) with platform screen doors (PSD) and one old station (Stockholm Sodra) without PSDs. This study evaluates the concentrations of airborne particulates at the new Odenplan station, focusing on the effects of traffic operation, system age and train movement. For comparison, the other two stations in the tunnel and an above-ground railway station (Solna) were also investigated. The new platform was clean prior to opening for traffic (the average concentration of PM10 and PM2.5 was 12 and 2 mu g m(-3), respectively). Substantial increases in the PM10 and PM2.5 levels were observed after it came into service, with the average concentrations increasing to 120 and 30 mu g m(-3) after 1 week and then to 175 and 35 mu g m(-3) after 3 months of operation. The train movement factor (traffic frequency and train stopping period) was found to have a strong effect on the coarse-sized particle concentrations (0.3-10 mu m). Comparable levels of PM10 and PM2.5 were measured at both the new Odenplan station and the old station, where the amount of traffic was similar. For the other new station, Stockholm City, where traffic was only half as frequent, the PM10 and PM2.5 levels were substantially lower.
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| 4. |
- Cha, Yingying, 1989-, et al.
(författare)
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Variation of airborne particulate levels in a newly built railway tunnel
- 2018
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Ingår i: Aerosol and Air Quality Research. - 1680-8584 .- 2071-1409.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The construction of a new railway tunnel for commuter trains in Stockholm was completed in 2017. It included two modern stations (Odenplan and Stockholm City) with platform screen doors (PSD) and one old station (Stockholm Södra) without PSDs. This study evaluates the concentrations of airborne particulates for the new stations, focussing on the effects of traffic operation, system age and train movement. For comparison, the other old station in the tunnel and an above-ground railway station (Solna) were also investigated. The new Odenplan platform was clean before its opening for traffic (12 and 2 μg/m3 for average PM10 and PM2.5, respectively). Substantial increases in the PM10 and PM2.5 concentrations were observed after it came into service. The average levels of PM10 and PM2.5 increased to 120 and 30 μg/m3 after one week of operation, and increased again to 175 and 35 μg/m3 after 3 months. The train movement factor (traffic frequency and train stop period) was found to have a strong effect on the particle concentrations of coarse sizes (0.3–10 μm). Comparable levels of PM10 and PM2.5 were measured at both the new station and the old station where the traffic frequency was similar. For the other new station, which had half the traffic frequency due to the station design with two separate platforms, the PM10 and PM2.5 levels were substantially lower.
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| 5. |
- Chen, Jing, et al.
(författare)
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Impact of relative humidity and water soluble constituents of PM2.5 on visibility impairment in Beijing, China
- 2014
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 14:1, s. 260-268
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Tidskriftsartikel (refereegranskat)abstract
- Beijing has been experiencing severe particulate pollution accompanying the fast growing population and economy. This study investigated the impact of PM2.5 and its water soluble organic and inorganic constituents on visual impairment in Beijing under different meteorological conditions. According to the analysis of PM2.5 samples collected in Spring 2012, water soluble species took up 38.1% of PM2.5 mass, among which NO3– was the most abundant constituent, followed by SO42–, NH4+ and water soluble organic matter. The correlation analysis between visibility and aerosol loadings as well as meteorological parameters revealed the dominant impact of meteorological conditions, relative humidity in particular, on visibility impairment over the mass concentration of PM2.5. Compared to the total aerosol loading of PM2.5, visibility was better correlated with the total mass of water soluble constituents (WSC). The visual range in Beijing was the most sensitive to both WSC and PM2.5 in the RH range of 30–70%. Severe visual impairment was observed for RH ≥ 70% with the least sensitivity to WSC and PM2.5. The effects of synoptic scale circulation on meteorological variables that affect air quality were also examined with the movement of a cold front as a case study. The findings have direct implications to region-wide policy-making and control strategies.
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| 6. |
- Dobric, Julia, et al.
(författare)
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Preschool Children’s Inhalation Rates Estimated from Accelerometers—A Tool to Estimate Children’s Exposure to Air Pollution
- 2022
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Ingår i: Aerosol and Air Quality Research. - : AAGR Aerosol and Air Quality Research. - 1680-8584 .- 2071-1409. ; 22:8
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Tidskriftsartikel (refereegranskat)abstract
- Children are particularly sensitive to air pollution exposure, and their personal exposures may differ significantly from those of adults. One key factor for understanding the personal inhaled dose of air pollutants is the respiratory minute ventilation (Ve). To estimate the amount of particles circulated through the lungs, 24 h averages of Ve are often used. These averages poorly capture variations in Ve during the day, and between individuals. We here develop and implement a concept to assess individual Ve of children, with minimal impact on their natural activity and movement pattern by using ActiGraph GT3X+ accelerometers. Activity of 136 preschool children in the ages 3 to 5 years was logged using accelerometers while the children attended their preschools during a week. A linear regression equation is developed and used for estimating Ve from the accelerometer data retrieved for each individual child. The results show large variations in weekly average Ve between individuals, ranging from 0.33 to 0.48 L min–1 kg–1. Over the days the averages of the individuals’ 1st and 3rd quartiles were 0.28 and 0.48 L min–1 kg–1, respectively. Outdoor activities resulted in a 17% higher Ve than indoor activities, which may be important to consider when estimating the inhaled dose of air pollutants since pollution levels and particle toxicities can be different indoors and outdoors. The observations motivate the use of individual values of Ve in exposure assessments and suggest that accelerometers are a suitable tool for estimating children’s individual Ve in their natural environment. Combined with time resolved local air pollution monitoring, these measurements can provide the basis of a more precise estimate of children’s inhaled dose of air pollutants. © The Author(s).
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| 7. |
- Gaita, Samuel Mwaniki, 1976, et al.
(författare)
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Characterization of Size-Fractionated Particulate Matter and Deposition Fractions in Human Respiratory System in a Typical African City: Nairobi, Kenya
- 2016
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 2071-1409 .- 1680-8584. ; 16:10, s. 2378-2385
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Tidskriftsartikel (refereegranskat)abstract
- Information from elemental and mass composition of size-fractionated airborne particle matter (PM) provides insightfulknowledge about their impact on human health, meteorology and climate. To attain insight into the nature of sizefractionatedPM from a typical African city, samples were collected from an urban background site in Nairobi, Kenya,during the months of August and September in 2007. PM samples ranging in size from 0.06 to 16 µm aerodynamicdiameter were collected on pre-weighed polycarbonate filters with 0.4 µm pore size using a nine-stage cascade impactor.Particles less than 0.06 µm were collected on a backup filter. A total of 170 samples were collected and analysed for traceelements using the Proton Induced X-Ray Emission (PIXE) technique. The analysis showed that Si, Fe and S dominated inall size ranges and displayed unimodal mass-size distribution whereas K, Cu, Zn and Pb, depicted bimodal mass-sizedistribution highlighting the multiplicity of their sources. To estimate human exposure to PM, deposition fractions of boththe coarse and fine PM in the human respiratory system were calculated. The deposited concentration was found to behighest in the head airways region compared to the tracheobronchial and pulmonary regions.
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| 8. |
- Imani Jajarmi, Ramin, 1987-, et al.
(författare)
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The Influence of Air Flow Velocity and Particle Size on the Collection Efficiency of Passive Electrostatic Aerosol Samplers
- 2019
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 19:2, s. 192-203
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Tidskriftsartikel (refereegranskat)abstract
- Electrostatic sampling is a promising method for the collection of bioaerosol particles. Although the underlying physics responsible for particle collection are well understood, the collection efficiency of simple passive electrostatic samplers is difficult to predict. Under these conditions, the collection efficiency becomes very sensitive to ambient air current and particle size, especially for submicron particles relevant for airborne virus transmission. In this paper, we compare two electrostatic aerosol sampler designs, a commercial product consisting of a flat collector plate located in the same plane as the charging needles and an axisymmetric design sampling directly to a liquid droplet. The aerosol particle collection efficiency of the samplers is investigated for particle size ranging from 0.25 to 2 µm while the air flow velocity surrounding the samplers is varied from 0.3 to 1 m s–1. For the planar design, at all ambient flow velocities, the submicron fraction of the particles captured originates in streamlines up to a maximum of 75 mm above the surface of the device collector, which greatly limits the volume of air being effectively sampled. The axisymmetric design features a non-monotonic capture efficiency as a function of particle size, with a minimum between 0.4 and 0.8 µm. The flow field in the inter-electrode region, captured using particle image velocimetry (PIV) reveals the presence of strong recirculation zones that can be responsible for the increased collection efficiency for very small particles.
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| 9. |
- Isa, Khairul Nizam Mohd, et al.
(författare)
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The Impact of Exposure to Indoor Pollutants on Allergy and Lung Inflammation among School Children in Selangor, Malaysia : An Evaluation Using Factor Analysis
- 2020
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 20:11, s. 2371-2383
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Tidskriftsartikel (refereegranskat)abstract
- A cross-sectional study of 470, 14-year-old students from 8 secondary schools located in sub-urban and urban areas in Hulu Langat district, Selangor, Malaysia was undertaken to determine the impact of atmospheric indoor air pollutants on atopy, asthma, respiratory symptoms and lung inflammation among school children. The students were surveyed using ISAAC and ECRHS questionnaires, their FeNO levels were measured and allergic skin prick tests were conducted. Active and passive sampling was used to measure the classroom indoor air concentration of NO2, CO2, formaldehyde, PM10, PM2.5, temperature and relative humidity. Linear mixed model, two-levels multiple logistic regression, PCA and SPC were applied to determine the complex relationship between respiratory symptoms, personal factors, FeNO levels and atmospheric indoor pollutants. 20.6% of students reported daytime breathlessness and 55.5% reported having rhinitis in the last 12 months. Atopy was prevalent in 57.7% of students, with predominant sensitization to Derp1 (51.9%) and Derf1 (47.9%) among doctor's diagnosed asthmatic students. Indoor air pollutants in urban area schools were significantly higher than those in sub-urban areas (p < 0.001). There was a significant association between exposure to PM10 (OR = 2.66, 95% CI: 1.33-5.30) with skin allergy symptoms in the past 12 months. The PCA suggested that the most prominent factor associated with increasing FeNO levels was PM10, with 73.5% of the variation. SPC predicted the pattern of FeNO at an upper confidence limit (UCL) of 104.21 ppb with increasing PM10 concentration in the classroom (UCL = 40.23 mu g m(-3)). Exposure to PM10 and PM2.5 significantly influenced the inflammation of the school children's lungs. Moreover, there were associations between self-reported wheezing, daytime and nocturnal attack of breathlessness with doctor's diagnosed asthma among school children.
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| 10. |
- Krecl, Patricia, et al.
(författare)
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Characterisation and Source Apportionment of Submicron Particle Number Size Distributions in a Busy Street Canyon
- 2015
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 15:1, s. 220-233
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Tidskriftsartikel (refereegranskat)abstract
- Street canyons are well-known hot spots due to the harmful exposure to high concentrations of atmospheric pollutants emitted mainly by motor vehicles. We report on measurements of air pollutants conducted in a street canyon in Stockholm (Sweden) in spring 2006. Particle number size distributions (PNSD) were measured in the 25-606 nm range, along with total particle number, light-absorbing carbon mass concentration (M-LAC), PM10, NOx, CO, traffic rate (TR), vehicle speed and meteorological variables. We used PNSD as input to the positive matrix factorisation (PMF) analysis to identify and apportion the pollutant sources. All pollutants showed distinct diurnal patterns, with highest concentrations in weekday mornings (08:00-09:00). TR was always higher on weekdays, except for the early hours (00:00-06:00). The raise in the weekend early-hour TR was accompanied by the largest MLAC of the day, a higher NOx/CO ratio compared to weekdays and a modal shift of PNSD towards larger diameters (47-56 nm), indicates a change in the vehicle fleet share to being dominated by diesel-run taxis. The largest contribution to the submicron particles was observed for winds blowing along the canyon, transporting particles emitted by vehicles accelerating from the traffic lights at the intersection, uphill towards the measurement site, and from the nearby streets. Three PMF factors were identified: local emissions from a mixed fleet dominated by gasoline engines, local traffic emissions highly impacted by diesel vehicles, and urban background aerosol. On average, gasoline-fuelled vehicles largely contributed to NOx, and particle number concentrations (54-65%), whereas M-LAC sources were dominated by diesel emissions, especially at weekends in the early hours (73%). The urban background contribution was rather low (4-13%) and with little dependence on the weekday. This work demonstrated how particle size distribution measurements, together with M-LAC, NOx and CO can be used to quantify the contribution from diesel and gasoline vehicles.
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| 11. |
- Kristensson, Adam, et al.
(författare)
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Size-Resolved Respiratory Tract Deposition of Sub-Micrometer Aerosol Particles in a Residential Area with Wintertime Wood Combustion
- 2013
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 13:1, s. 24-35
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Tidskriftsartikel (refereegranskat)abstract
- Particle size distributions and hygroscopic growth were studied in a town in Sweden with extensive emissions from wood combustion. The average deposited fraction of particle number, surface area and volume dose in the human respiratory tract was estimated using the data set, as well as the typical deposition pattern of the two dominant particle source types: wood combustion and traffic exhaust. As far as we know, this is the first report on the deposited fraction and hygroscopicity of ambient particles from domestic wood combustion in the literature. The use of PM2.5 as a substitute for the deposited dose was also tested. Source/receptor modeling and the hygroscopicity measurements showed that wood combustion and traffic exhaust are dominant sources, and that these particles have a low water uptake. Number fractions of 38 and 69% of the wood combustion and traffic particles, respectively, were deposited in the respiratory tract, and 53% of the particles were deposited as an average for the whole period. The deposited fraction of the surface area and volume dose was also calculated for wood combustion particles, with the result being 22% for both parameters. The results also revealed that the PM2.5 average over more than 10 hours correlated well (r(2) > 0.80) with the deposited surface area and volume dose. This means that PM2.5 can be used as proxy for the deposited dose when examining health effect relationships during short-term exposure studies if the averaging time is sufficient, while a PM2.5 proxy is not recommended for shorter averaging times.
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| 12. |
- Langner, J., et al.
(författare)
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Model-simulated source contributions to PM2.5 in Santiago and the central region of Chile
- 2020
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 2071-1409 .- 1680-8584. ; 20:5, s. 1111-1126
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Tidskriftsartikel (refereegranskat)abstract
- The contributions to PM2.5 from different emission sectors across central Chile and the Santiago metropolitan area during summer/fall and winter have been evaluated using a chemical transport model. The simulations generally underestimate the mean PM2.5 concentrations compared to measurements conducted at stations in Santiago that belong to the Chilean National Air Quality Information System (SINCA). The potential reasons for this discrepancy include underestimated direct PM2.5 emissions, missing emissions for semi-and intermediately volatile organic compounds (SVOCs and IVOCs) and overestimated wind speeds in the simulations. The simulated winter PM2.5 concentrations in Santiago are lower and higher than the values observed during nighttime, and daytime and late evening, respectively, which may be related to excessive simulated wind speeds, as well as to uncertainties in the diurnal variation in the emissions. During summer/fall, the simulated diurnal variation better agrees with the observations, but the peak concentrations during the morning are underestimated, whereas those during the evening are overestimated. The simulated contributions of different aerosol components to the PM2.5 at one station in Santiago are all lower than the observed values, except for elemental carbon equivalent black carbon (BCe), which exhibit comparable or higher levels in the simulations. The absolute differences are the largest for the total organic matter, whereas the relative differences are the largest for BCe and ammonium. The simulated sector contributions indicate that emissions originating from transport and construction machinery dominate the PM2.5 in Santiago; however, residential wood combustion is the primary source in other urban areas of central Chile, except near major point sources. Away from urban areas, traffic routes and major industrial sources, secondary inorganic aerosol (SIA) is estimated to be the largest component of the aerosol, whereas the simulated secondary organic aerosol (SOA) only contributes a small fraction.
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| 13. |
- Maji, K. J., et al.
(författare)
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Assessment of city level human health impact and corresponding monetary cost burden due to air pollution in India taking Agra as a model city
- 2017
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 17:3, s. 831-842
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Tidskriftsartikel (refereegranskat)abstract
- Objectives of the present study are to provide quantitative estimations of air pollution health impacts and monetary burden on people living in Agra city, the fourth most populated city in Uttar Pradesh, India. To estimate the direct health impacts of air pollution in Agra city during year 2002 to 2014, ‘Risk of Mortality/Morbidity due to Air Pollution’ model was used which is adopted from air quality health impact assessment software, developed by world health organization (WHO). Concentrations of NO2, SO2 and PM10 have been used to assess human health impacts in terms of attributable proportion of the health outcome as- annual number of excess cases of total mortality, cardiovascular mortality, respiratory mortality, hospital admission chronic obstructive pulmonary disease (COPD), hospital admission respiratory disease and hospital admission cardiovascular disease and it was observed that attributable number of cases were 1325, 908, 155, 138, 1230 and 348 respectively in year 2002. However, after thirteen years these figures increased to 1607, 1095, 189, 167, 1568 and 394 respectively. From these results, it was observed that from 2002 to 2014, the attributable number of cases increased almost by 13.43 to 27.52%. As a result, the monetary cost burden due to air pollution related health effects also increased very highly; it was 67.99 million US$ in 2002, which transformed into 254.52 million US$ in 2014. In future, if air quality continues to follow current pollutant concentration trend, the monetary cost burden will reach a level of US$ 570.12 million in year 2020, which is not only a thoughtful matter but also a threatful matter and it signifies the importance of rectification measures for air quality in Agra city.
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| 14. |
- Martinsson, Johan, et al.
(författare)
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Evaluation of delta C-13 in Carbonaceous Aerosol Source Apportionment at a Rural Measurement Site
- 2017
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 17:8, s. 2081-2094
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Tidskriftsartikel (refereegranskat)abstract
- The stable isotope of carbon, C-13, has been used in several studies for source characterization of carbonaceous aerosol since there are specific signatures for different sources. In rural areas, the influence of different sources is complex and the application of delta C-13 for source characterization of the total carbonaceous aerosol (TC) can therefore be difficult, especially the separation between biomass burning and biogenic sources. We measured delta C-13 from 25 filter samples collected during one year at a rural background site in southern Sweden. Throughout the year, the measured delta C-13 showed low variability (-26.73 to -25.64%). We found that the measured delta C-13 did not correlate with other commonly used source apportionment tracers (C-14, levoglucosan). delta C-13 values showed lower variability during the cold months compared to the summer, and this narrowing of the delta C-13 values together with elevated levoglucosan concentrations may indicate contribution from sources with lower delta C-13 variation, such as biomass or fossil fuel combustion. Comparison of two Monte Carlo based source apportionment models showed no significant difference in results when delta C-13 was incorporated in the model. The insignificant change of redistributed fraction of carbon between the sources was mainly a consequence of relatively narrow range of delta C-13 values and was complicated by an unaccounted kinetic isotopic effect and overlapping delta C-13 end-member values for biomass burning and biogenic sources.
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| 15. |
- Martinsson, Johan, et al.
(författare)
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On the Relationship of Biogenic Primary and Secondary Organic Aerosol Tracer Compounds on the Aethalometer Model Parameters
- 2020
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 2071-1409 .- 1680-8584. ; 20:12, s. 2654-2668
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Tidskriftsartikel (refereegranskat)abstract
- The aethalometer model has shown to offer a fast, inexpensive and robust method for source apportionment. The method relies on aerosol light absorption attribution, mass balance of the total carbon and results in a fraction of unaccounted, residual carbon that has been associated to biogenic carbon due to its presumably non-light absorbing properties. This residual carbon and its relation to tracers of biogenic primary and secondary organic aerosol was investigated at a rural measurement station in Sweden. Special focus is devoted to 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a second-generation oxidation compound in biogenic secondary organic aerosols. The results show that the residual carbon and the biogenic tracers show a high degree of correlation and that the tracers were highly seasonally dependent with largest carbon contributions during summer. MBTCA showed positive correlation with the aethalometer model derived absorption coefficients from fossil fuel carbonaceous aerosol, stressing the suspicion that biogenic aerosol might be falsely apportioned to fossil fuel carbon in the aethalometer model. MBTCA showed an increasing degree of correlation with higher aethalometer absorption coefficient wavelengths. However, spectrophotometric analysis revealed that the ambient concentrations of MBTCA are most likely to low to give a significant response in the aethalometer. These results support the application of MBTCA as a molecular tracer for biogenic secondary organic aerosol and indicates that a large fraction of the aethalometer model residual carbon is of biogenic origin. Future studies should investigate the light absorbing properties of precursor monoterpenes such as α-pinene, their oxidation products and eventual influence on the aethalometer model.
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| 16. |
- Molnár, Peter, 1967, et al.
(författare)
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Source Apportionment of PM2.5 Using Positive Matrix Factorization (PMF) and PMF with Factor Selection
- 2014
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- Personal exposure, indoor, residential outdoor and urban background particulate matter (PM2.5) samples were collected in parallel, for 30 participants and analyzed for their chemical content. Source apportionments for the separate microenvironments were performed using conventional positive matrix factorization (PMF), and for the combined dataset, applying a new PMF method with factor selection. Regional sources were the largest contributor to the sampled PM2.5 in all microenvironments and accounted for 69% in urban background; 55% and 54% in residential outdoor and indoor environment, respectively; and 40% of personal exposure. For personal exposure, personal activities accounted for 21% (2.2 mu g/m(3)), and constituted the main difference in total mass concentration between personal exposure and the other microenvironments. The PMF method with factor selection was found to be a useful tool in the PMF analysis of multiple microenvironments, since ambient contributions to indoor and personal exposure are less likely to be distorted or misinterpreted. The possibility to more correctly estimate the source contributions will increase by combining the datasets for the different microenvironments into a larger dataset and using the PMF with factor selection method.
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| 17. |
- Owoade, Oyediran Kayode, et al.
(författare)
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Spatial-temporal Variation and Local Source Identification of Air Pollutants in a Semi-urban Settlement in Nigeria Using Low-cost Sensors
- 2021
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 21:10
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Tidskriftsartikel (refereegranskat)abstract
- Low-cost sensors were deployed at five locations in a growing, semi-urban settlement in southwest Nigeria between June 8 and July 31, 2018 to measure particulate matter (PM2.5 and PM10), gaseous pollutants (CO, NO, NO2, O3 and CO2), and meteorological variables (air temperature, relative humidity, wind speed and wind-direction). The spatial and temporal variations of measured pollutants were determined, and the probable sources of pollutants were inferred using conditional bivariate probability function (CBPF). Hourly PM2.5 and PM10 concentrations ranged from 20.7 ± 0.7 to 36.3 ± 1.6 µg m–3 and 47.5 ± 1.5 to 102.9 ± 5.6 µg m–3, respectively. Hourly gaseous pollutant concentrations ranged from 348 ± 132 to 542 ± 200 ppb CO, 21.5 ± 7.2 ppb NO2 and 57.5 ± 11.3 to 64.4 ± 14.0 ppb O3. Kruskal-Wallis ANOVA on ranks determined statistically significant spatial differences in the hourly-average pollutant concentrations. Diel variation analyses indicated that CO2, PM2.5, and PM10 peaked in the early hours of most days, O3 at noon while NO, NO2, and CO peaked in the evening. Most pollutants were of anthropogenic origins and exhibited the highest contributions from the southwest at most sampling locations. There were strong similarities between pollutants source contribution at two of the monitoring sites that were in residential areas with a frequently used paved road. Mitigation strategies need to be established to avoid further deterioration of ambient air quality that negatively affect public health.
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| 18. |
- Rissler, Jenny, et al.
(författare)
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A set-up for respiratory tract deposition efficiency measurements (15–5000 nm) and first results for a group of children and adults
- 2017
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Ingår i: Aerosol and Air Quality Research. - : AAGR Aerosol and Air Quality Research. - 1680-8584 .- 2071-1409. ; 17:6, s. 1244-1255
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to airborne particulate matter is associated with a number of negative health effects ranging from respiratorydiseases to systemic effects and cancer. One important factor for understanding the health effects is the individual variationin the respiratory tract deposition of inhaled particles. In this study, we describe an experimental set-up for size-resolvedmeasurements of the lung deposited fraction of airborne particles, covering the diameter range from 15 to 5000 nm. Theset-up includes a system for generating a stable aerosol with a sufficiently broad size distribution. We used a scanningmobility particle sizer and an aerodynamic particle sizer to determine particle number and size. The set-up was used toinvestigate individual differences in the deposition fraction (DF) of particles in the respiratory tract for a group of 67subjects of both sexes aged 7–70 years. The measured DF was applied to two model aerosols, one representing an urbanenvironment and one a rural environment, and the particle deposition rates were derived (i.e., the deposited amount ofparticles per unit time). Furthermore, the deposition rates were normalized to lung surface area and body mass – two dosemeasures that are considered relevant for the health effects of airborne particles. In addition to validation of the set-up, weshow that there is a large individual variation in DF, with some subjects having a DF that is more than twice as high as thatof others. Although we observe differences in the DF between different subgroups, most individual variation wasexplained neither by age nor by gender. When normalizing the deposition rates to lung surface area or body mass, thedeposition rates of children become significantly higher than those of adults. Furthermore, the individual variability islarger for the lung surface area or body mass normalized deposition rates than for DF
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| 19. |
- Salvador, Christian Mark, 1989, et al.
(författare)
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Assessment of Impact of Meteorology and Precursor in Long-term Trends of PM and Ozone in a Tropical City
- 2022
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Long-term trends of atmospheric pollutants, particularly ozone (O-3) and particulate matter (PM) provide a direct evaluation of the response of the atmosphere to the environmental policies and the variability of anthropogenic and biogenic emissions. Here, we report the assessment of the temporal evolution of the air quality in a tropical urban city (Butuan) in the southern Philippines by evaluating the trends of meteorological conditions (i.e., temperature, R.H., boundary layer height), air pollutants (i.e., PM2.5, NO2, O-3) and their precursors (Benzene, Toluene, and Xylene) from 2014 to 2020. During the seven-year measurement, the mean PM2.5 and PM10 mass concentrations were 8.7 +/- 3.9 and 24.3 +/- 12.0 mu g m(-3), with no single day exceeded the daily PM limit. The max concentrations of aerosol occurred during the dry season when the loss of particles through wet deposition was limited. Speciation of PM2.5 indicated that fine aerosol was dominated by sea salt and organic matter (OM). Analysis of the ratio of OM and sulfate indicated that the main source of pollution in the city was wildfire/biomass burning. The average O-3 and NO2 mixing ratios during the same period were 22.3 +/- 9.5 ppb and 8.1 +/- 5.4 ppb while increasing at the rate of 0.409 ppb year(-1) and 0.683 ppb year(-1). The highest O-3 concentration occurred during the summer months when photochemistry enhanced the formation of tropospheric O-3. The increasing O-3 trend was attributed to the contribution of anthropogenic VOCs (AVOCs), based on their ozone-forming potentials (OFPs). The seven-year measurement also showcased the variability of the atmospheric pollutants during the COVID-19 pandemic of 2020, when O-3 substantially increased due to reduced vehicle transport activities. Overall, our results provide insights to better comprehend the sources of the variability of O-3 and PM on a long-term temporal scale, as well as implications on relevant environmental policies in controlling air pollutants in a tropical developing region.
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| 20. |
- Shaltout, Abdallah, et al.
(författare)
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Elemental Composition of PM2.5 Particles Sampled in Industrial and Residential Areas of Taif, Saudi Arabia
- 2013
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 13:4, s. 1356-1364
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the first part of a project conducted to evaluate the trace element composition of atmospheric aerosol particles (PM2.5) and to determine their influence on air quality in Taif city, Saudi Arabia. PM2.5 particles were collected from two different sites (industrial and residential) in Taif during the summer of 2011. The industrial site was situated in the largest industrial area of Taif, and the residential site was situated in the city’s most crowded area. PM2.5 samples were collected on polycarbonate filters using a cyclonic collector. Each sample was collected over a 24 hour period and new samples were collected weekly. Average PM2.5 concentrations of 47 ± 15 and 46 ± 31 μg/m3 were seen in the industrial and residential areas, respectively. An Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer with a Mo secondary target was used to analyze the solid samples because of the relative simplicity of the technique for filter analysis. The use of a Mo secondary target is advantageous, because it decreases the impact of continuum radiation from the X-ray tube and increases the signal to background ratio. Quantitative X-ray Analysis Software (PyMca) was used to perform quantitative analysis of the atmospheric aerosols. The analysis resulted in detected concentrations for sixteen elements; Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Pb and Black Carbon (BC). Using Principal Component Analysis (PCA) it was possible to distinguish between natural and anthropogenic sources. The measured concentrations of the potentially hazardous trace elements Cu, Cr, Mn, Ni and Pb were below the limits defined by international guidelines and national standards for ambient air quality. However, further long-term research will be required to validate the quantification of trace elements in particulate matter in Taif.
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| 21. |
- Shang, Xiaona, et al.
(författare)
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Identification and Chemical Characteristics of Distinctive Chinese Outflow Plumes Associated with Enhanced Submicron Aerosols at the Gosan Climate Observatory
- 2018
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 18:2, s. 330-342
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Tidskriftsartikel (refereegranskat)abstract
- From October till November in 2010 and during March of 2011, when Chinese outflow events were frequently encountered, the chemical composition of submicron particles (PM1.0) was determined hourly using a particle-into-liquid sampler at the Gosan Climate Observatory. Three distinctive pollution plume types were identified: haze aerosols impacted by biomass combustion, nanoparticle bursts associated with outflow from Beijing, and saline soil particles from salt deposits. The highest PM1.0 concentration was observed in a fall haze event, under near-stagnant high-pressure synoptic conditions that were characterized by the lowest visibility (< 5 km) and the highest K+ and OC concentrations, indicating the influence of biomass combustion. When strong high-pressure systems develop in China, they efficiently export fresh urban emissions from Beijing to the study region, as distinguished by nanoparticle bursts of > 10(4) cm(-3) with highly elevated SO2 levels, even during the night. When air masses move rapidly from northeastern China to Gosan under strong wind conditions, the Ca2+ concentration, along with that of Cl- and Na+, is enhanced in PM1.0, which is attributed to the influence of saline transport from dry lakes. The results of this study reveal compositional details and information on both number and mass concentration for different PM1.0 plumes from anthropogenic and natural sources, all of which are associated with different kinds of Chinese outflow events.
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| 22. |
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