| 1. |
- Adachi, Kouji, et al.
(author)
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Composition and mixing state of individual aerosol particles from northeast Greenland and Svalbard in the Arctic during spring 2018
- 2023
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In: Atmospheric Environment. - 1352-2310 .- 1873-2844. ; 314
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Journal article (peer-reviewed)abstract
- The Arctic region is warming about four times faster than the rest of the globe, and thus it is important to understand the processes driving climate change in this region. Aerosols are a significant component of the Arctic climate system as they form ice crystals and liquid droplets that control the dynamics of clouds and also directly interact with solar radiation, depending on the compositions and mixing states of individual particles. Here, we report on the characteristics of submicron-sized aerosol particles using transmission electron microscopy obtained at two high Arctic sites, northeast Greenland (Villum Research Station) and Svalbard (Zeppelin Observatory), during spring 2018. The results showed that a dominant compound in the submicron-sized spring aerosols was sulfate, followed by sea salt particles. Both model simulations and observations at the Zeppelin Observatory showed that sea salt particles became more prevalent when low-pressure systems passed by the station. Model simulations indicate that both sampling sites were affected by diffused and diluted long-range transport of anthropogenic aerosols from lower latitudes with negligible influences of biomass burning emissions during the observation period. Overall, the composition of measured aerosol particles from the two Arctic sites was generally similar and showed no apparent variation except for the sea salt fractions. This study shows a general picture of high Arctic aerosol particles influenced by marine sources and diffused long-range transport of anthropogenic sources during the Arctic spring period. These results will contribute to a better knowledge of the aerosol composition and mixing state during the Arctic spring, which helps to understand the contributions of aerosols to the Arctic climate.
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| 2. |
- Elihn, Karine, et al.
(author)
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Air quality impacts of a large waste fire in Stockholm, Sweden
- 2023
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 315
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Journal article (peer-reviewed)abstract
- Fires in waste facilities are a common occurrence. Since many waste facilities are located adjacent to densely populated areas, these fires could potentially expose large populations to the emitted pollutants. However, at the moment there are only few field studies investigating the impact of waste fire emissions on air quality since the unpredictable nature of these events makes them challenging to capture. This study investigated the impact of a large and persistent un-prescribed fire in a waste storage facility in Stockholm county, Sweden, on the local air quality of two residential areas in close proximity to the fire. In-situ measurements of particulate matter, black carbon and nitrogen oxide concentrations were conducted both during open burning and after the fire was fully covered. In addition, filter samples were collected for offline analysis of organic composition, metal content and toxicity. Strongly increased concentrations of PM10, PM2.5 and black carbon were found during the open burning period, especially when the wind was coming from the direction of the fire. In addition, elevated concentrations of particulate heavy metals and polycyclic aromatic hydrocarbons were observed in the air during the open burning period. These results show that waste fires can have a strong impact on the air quality of nearby residential areas.
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| 3. |
- Lunder Halvorsen, Helene, et al.
(author)
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Spatial variability and temporal changes of POPs in European background air
- 2023
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 299
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Journal article (peer-reviewed)abstract
- Concentration data on POPs in air is necessary to assess the effectiveness of international regulations aiming to reduce the emissions of persistent organic pollutants (POPs) into the environment. POPs in European background air are continuously monitored using active- and passive air sampling techniques at a limited number of atmospheric monitoring stations. As a result of the low spatial resolution of such continuous monitoring, there is limited understanding of the main sources controlling the atmospheric burdens of POPs across Europe. The key objectives of this study were to measure the spatial and temporal variability of concentrations of POPs in background air with a high spatial resolution (n = 101) across 33 countries within Europe, and to use observations and models in concert to assess if the measured concentrations are mainly governed by secondary emissions or continuing primary emissions. Hexachlorobenzene (HCB) was not only the POP detected in highest concentrations (median: 67 pg/m3), but also the only POP that had significantly increased over the last decade. HCB was also the only POP that was positively correlated to latitude. For the other targeted POPs, the highest concentrations were observed in the southern part of Europe, and a declining temporal trend was observed. Spatial differences in temporal changes were observed. For example, γ-HCH (hexachlorocyclohexane) had the largest decrease in the south of Europe, while α-HCH had declined the most in central-east Europe. High occurrence of degradation products of the organochlorine pesticides and isomeric ratios indicated past usage. Model predictions of PCB-153 (2,2’,4,4’,5,5’-hexachlorobiphenyl) by the Global EMEP Multi-media Modelling System suggest that secondary emissions are more important than primary emissions in controlling atmospheric burdens, and that the relative importance of primary emissions are more influential in southern Europe compared to northern Europe. Our study highlights the major advantages of combining high spatial resolution observations with mechanistic modelling approaches to provide insights on the relative importance of primary- and secondary emission sources in Europe. Such knowledge is considered vital for policy makers aiming to assess the potential for further emission reduction strategies of legacy POPs.
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| 4. |
- Vechi, Nathalia T., et al.
(author)
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Ammonia and methane emissions from dairy concentrated animal feeding operations in California, using mobile optical remote sensing
- 2023
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In: Atmospheric Environment. - : Elsevier BV. - 1873-2844 .- 1352-2310. ; 293
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Journal article (peer-reviewed)abstract
- Dairy concentrated animal feeding operations (CAFOs) are significant sources of methane (CH4) and ammonia (NH3) emissions in the San Joaquin Valley, California. Optical techniques, namely, remote sensing by Solar Occultation Flux (SOF) and Mobile extractive FTIR (MeFTIR), were used to measure NH3 air column and ground air concentrations of NH3 and CH4, respectively. Campaigns were performed in May and October 2019 and covered 14 dairies located near Bakersfield and Tulare, California. NH3 and CH4 emission rates from single CAFOs averaged 101.9 ± 40.6 kgNH3/h and 437.7 ± 202.0 kgCH4/h, respectively, corresponding to emission factors (EFs) per livestock unit of 9.1 ± 2.7 gNH3/LU/h and 40.1 ± 17.8 gCH4/LU/h. The NH3 emissions had a median standard uncertainty of 17% and an expanded uncertainty (95% Confidence Interval (CI)) of 37%; meanwhile, CH4 emissions estimates had greater uncertainty, median of 25% and 53% (in the 95% CI). Decreasing NH3 to CH4 ratios and NH3 EFs from early afternoon (13:00) to early night (19:00) indicated a diurnal emission pattern with lower ammonia emissions during the night. On average, measured NH3 emissions were 28% higher when compared to daytime emission rates reported in the National Emissions Inventory (NEI) and modeled according to diurnal variation. Measured CH4 emissions were 60% higher than the rates reported in the California Air Resources Board (CARB) inventory. However, comparison with airborne measurements showed similar emission rates. This study demonstrates new air measurement methods, which can be used to quantify emissions over large areas with high spatial resolution and in a relatively short time period. These techniques bridge the gap between satellites and individual CAFOs measurements.
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| 5. |
- Vouitsis, Ilias, et al.
(author)
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Transport-related airborne nanoparticles : Sources, different aerosol modes, and their toxicity
- 2023
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 301
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Research review (peer-reviewed)abstract
- Nanoparticle emissions from transport are of considerable importance because of their dominance in terms of particle number concentration in most urban atmospheres. Nanoparticles may carry toxic substances, posing a serious threat to pedestrians, passengers and residents. The road sector has been studied intensively in both academia and industry and considerable knowledge has already been gathered. Shipping is also a significant source of nanoparticles both at the global and the European level and may be responsible for cardiopulmonary diseases and lung cancer at the global level, while ship emissions are known as one of the least regulated sources of pollutants. Aviation nanoparticle emissions have also received increasing attention in recent years because of the rapid growth of air transport volumes and the expected expansion to meet capacity needs for future years. Exhaust nanoparticle emissions from diesel rail transport are not very well known and only a few sources addressing actual emission rates are available. All modes of transport are sources of non-exhaust nanoparticle number emission associated with the tire, brake, and road/rail surface wear and tear. This paper provides a literature review to identify the different aerosol modes (i.e., primary, delayed primary, and secondary) from each transport source (road, shipping, aviation, rail), in both laboratory and field tests and to explore their toxicity relevance. The review focuses on nanoparticles (<100 nm) and investigates both exhaust and non-exhaust emissions. We present details on nanoparticles produced by transport sources in the urban environment and parameters that influence nanoparticle emissions. Also, we review the potential relationship between the different aerosol modes and their toxicity effects and point out some issues concerning nanoparticle collection for chemical and toxicity characterization. As regards the toxicity part, it is concluded that transport sources emit large number of nanoparticles which may pose a health risk. They can damage the respiratory tract and lungs, thus playing a crucial role in the physiology of pulmonary pathologies. These nanoparticles can also affect other organs, and the cardiovascular, nervous, and reproductive systems. The combination of oxidative stress, mitochondrial damage, inflammation, and activation of apoptosis, are the initiators of the systemic toxicity of nanoparticles, triggered by a unique combination of heavy metals and organic compounds present in combustion products.
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| 6. |
- Yang, Liu, et al.
(author)
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Exposure to greenness, air pollution and respiratory health among pre-school children in northern China
- 2023
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In: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 298
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Journal article (peer-reviewed)abstract
- Background: Evidence from developed countries on the association between greenspace and childhood respira-tory health has been inconsistent whilst such evidence is largely lacking in the developing world where rapid urbanization is occurring. This study aimed to investigate the associations between surrounding greenness, air pollution and respiratory health among pre-school children in a rapidly developing city in China.Methods: We recruited 2920 pre-school children in Taiyuan city. Greenness exposure was represented by the Normalized Difference Vegetation Index (NDVI) which combined estimations based on a weighted mean that children spend time both in kindergarten and home (75% home, 25% kindergarten). Air pollution exposures were estimated from a land-use-regression model which was also calculated based on a weighted mean as with greenness. Logistic regression was performed to assess the relationships between greenness, air pollution and respiratory symptoms.Results: Greenness had negatively impacted respiratory health among pre-school children in Taiyuan city, particularly for current dry cough at night. A 0.1-unit increment for NDVI300m was associated with an Odds Ratio (OR) of 2.45 (95%CI: 1.33-4.53) for dry cough at night. The associations were robust after adjusting for air pollution and road condition. No statistically significant associations were found between air pollution and any symptoms. The mediating effect of air pollution on dry cough at night with greenness was not observed.Conclusion: Our study found that within different buffers, a higher level of greenness was consistently associated with a higher risk of dry cough at night among pre-school children. This finding has indicated that environmental policies on urban greening should be scientifically justified to protect respiratory health among young children.
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| 7. |
- Yi, Xin, et al.
(author)
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Compound-specific radiocarbon analysis of benzene polycarboxylic acids for source apportionment of polyaromatic organic matter in ambient aerosols
- 2023
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In: Atmospheric Environment. - 1352-2310 .- 1873-2844. ; 307
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Journal article (peer-reviewed)abstract
- Polyaromatic organic matter (POM) is an important group of pollutants and light absorbers in ambient aerosols, which consists of a wide range of chemicals with fused benzene rings. POM in ambient aerosols is mainly derived from the incomplete combustion of fossil fuel and biomass. Source apportionment of POM is crucial for advising efficient mitigation of anthropogenic emissions, but that is a challenge due to the complicated composition of POM and ambient aerosols. Benzene polycarboxylic acids (BPCAs) have recently been introduced as molecular markers of atmospheric POM. Compound-specific radiocarbon analysis of BPCAs is expected to be a powerful tool for apportioning fossil sources and contemporary (i.e., biomass burning) sources of POM in ambient aero-sols, yet this application is still lacking. We developed a method for radiocarbon analysis of BPCAs substituted with 3-6 carboxylic groups (B6CA, B5CA, B4CAs and B3CAs). BPCAs were isolated with preparative liquid chromatography with high recoveries (>= 85%). The method is validated with reference materials with fossil and contemporary radiocarbon signatures. Successful radiocarbon analysis of BPCAs was achieved for these reference materials after correcting for the presence of average blanks (B6CA: 1.2 +/- 0.2 mu g, B5CA: 2.3 +/- 0.6 mu g, individual B4CAs: 2.7 +/- 0.2 mu g and individual B3CAs: 6.9 +/- 0.7 mu g). Source apportionment of POM based on radiocarbon
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| 8. |
- Holzinger, R., et al.
(author)
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A signature of aged biogenic compounds detected from airborne VOC measurements in the high arctic atmosphere in March/April 2018
- 2023
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In: Atmospheric Environment. - 1352-2310. ; 309
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Journal article (peer-reviewed)abstract
- During the PAMARCMiP 2018 campaign (March and April 2018) a proton-transfer-reaction mass spectrometer (PTR-MS) was deployed onboard the POLAR 5 research aircraft and sampled the high Arctic atmosphere under Arctic haze conditions. More than 100 compounds exhibited levels above 1 pmol/mol in at least 25% of the measurements. We used acetone mixing ratios, ozone concentrations, and back trajectories to identify periods with and without long-range transport from continental sources. During two flights, surface ozone depletion events (ODE) were observed that coincided with enhanced levels of acetone, and methylethylketone, and ice nucleating particles (INP).Air masses with continental influence contained elevated levels of compounds associated with aged biogenic emissions and anthropogenic pollution (e.g., methanol, peroxyacetylnitrate (PAN), acetone, acetic acid, meth-ylethylketone (MEK), proprionic acid, and pentanone). Almost half of all positively detected compounds (>100) in the high Arctic atmosphere can be associated with terpene oxidation products, likely produced from mono-terpenes and sesquiterpenes emitted from boreal forests. We speculate that the transport of biogenic terpene emissions may constitute an important control of the High Arctic aerosol burden. The sum concentration of the detected aerosol forming vapours is-12 pmol/mol, which is of the same order than measured dimethylsulfide (DMS) mixing ratios and their mass density corresponds to approximately one fifth of the measured non-black -carbon particles.
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