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Oxyfuel combustion can reduce CO2 emissions from fossil fuels. Hence, it is currently being investigated for potential use in oil shale-fired power plants, which currently produce most of Estonia’s electricity. Here, experiments were performed with kukersite oil shale for both oxyfuel and conventional combustion in a 60 kWth circulating fluidized bed combustor. In this paper, we provide data on the ash composition including mineral compositions and heavy metal concentrations. Oxyfuel conditions did not noticeably influence the concentrations of heavy metals in the ash but did have significantly lower amounts of free lime because of inhibition of the carbonate decomposition reactions. The results suggest that oxyfuel combustion would produce no significant problems in terms of the behavior of the ash or the fate of heavy metals contained in the ash.

In this study, oil shale combustion emission measurements were conducted in a 60 kWth Circulating Fluidized Bed combustion test facility located in a laboratory-type environment. A comprehensive set of instruments including a nitrate-ion-based Chemical Ionization Atmospheric Pressure interface Time-of-Flight Mass Spectrometer, a Soot-Particle Aerosol Mass Spectrometer, and a Potential Aerosol Mass (PAM) chamber was utilized to investigate the chemical composition and concentrations of primary and secondary emissions in oil shale combustion. In addition, the size distribution of particles (2.5–414 nm) as well as concentration and composition of gaseous precursors were characterized. Altogether 12 different experiments were conducted. Primary emissions were studied in seven experiments and aged emissions using PAM chamber in five experiments. Combustion temperatures and solid fuel circulation rates varied between different experiments, and it was found that the burning conditions had a large impact on gaseous and particulate emissions. The majority of the combustion particles were below 10 nm in size during good burning whereas in poor burning conditions the emitted particles were larger and size distributions with 2–3 particle modes were detected. The main submicron particle chemical component was particulate organic matter (POM), followed by sulfate, chloride, nitrate, and ammonium. The secondary particulate matter formed in the PAM chamber was mostly POM and the concentration of POM was many orders of magnitude higher in aged aerosol compared to primary emissions. A significant amount of aromatic volatile organic compounds (VOCs) was measured as well. VOCs have the potential to go through gas-to-particle conversion during the oxidation process, explaining the observed high concentrations of aged POM. During good combustion, when VOC emissions were lower, over 80% of SO2 was oxidized either to gaseous H2SO4 (37%) or particulate sulfate (46%) in the PAM chamber, which mimic the atmospheric processes taken place in the ambient air after few days of emission. publishedVersion

Objective To evaluate the short term associations between nitrogen dioxide (NO2) and total, cardiovascular, and respiratory mortality across multiple countries/regions worldwide, using a uniform analytical protocol. Design Two stage, time series approach, with overdispersed generalised linear models and multilevel meta-analysis. Setting 398 cities in 22 low to high income countries/regions. Main outcome measures Daily deaths from total (62.8 million), cardiovascular (19.7 million), and respiratory (5.5 million) causes between 1973 and 2018. Results On average, a 10 μg/m3 increase in NO2 concentration on lag 1 day (previous day) was associated with 0.46% (95% confidence interval 0.36% to 0.57%), 0.37% (0.22% to 0.51%), and 0.47% (0.21% to 0.72%) increases in total, cardiovascular, and respiratory mortality, respectively. These associations remained robust after adjusting for co-pollutants (particulate matter with aerodynamic diameter ≤10 μm or ≤2.5 μm (PM10 and PM2.5, respectively), ozone, sulfur dioxide, and carbon monoxide). The pooled concentration-response curves for all three causes were almost linear without discernible thresholds. The proportion of deaths attributable to NO2 concentration above the counterfactual zero level was 1.23% (95% confidence interval 0.96% to 1.51%) across the 398 cities. Conclusions This multilocation study provides key evidence on the independent and linear associations between short term exposure to NO2 and increased risk of total, cardiovascular, and respiratory mortality, suggesting that health benefits would be achieved by tightening the guidelines and regulatory limits of NO2., HaK was supported by the National Natural Science Foundation of China (92043301, 82030103, and 91843302) and China Medical Board Collaborating Program (16-250). AG and FS were supported by the Medical Research Council, UK (MR/M022625/1), the Natural Environment Research Council, UK (NE/R009384/1), and the European Union’s Horizon 2020 Project Exhaustion (820655). VH was supported by the Spanish Ministry of Science and Innovation (PCIN-2017-046), and the German Federal Ministry of Education and Research (01LS1201A2). YH and MH were supported by the Environment Research and Technology Development Fund (JPMEERF15S11412) of the Environmental Restoration and Conservation Agency, Japan. JK and AU were supported by the Czech Science Foundation (18-22125S). ST was supported by the Shanghai Municipal Science and Technology Commission (18411951600). Y-LLG was supported by a Career Development Fellowship of the Australian National Health and Medical Research Council (APP1163693). SL was supported by an Early Career Fellowship of the Australian National Health and Medical Research Council (APP1109193). JJKJJ and NR were supported by the Academy of Finland (310372). The funders had no role in considering the study design or in the collection, analysis, interpretation of data, writing of the report, or decision to submit the article for publication.

Ambient ammonia (NH3) measurements were performed with a mobile platform in three European cities: Zurich (Switzerland), Tartu (Estonia) and Tallinn (Estonia) deploying an NH3 analyzer based on cavity ring-down spectroscopy. A heated inlet line along with an auxiliary flow was used to minimize NH3 adsorption onto the inlet walls. In addition, a detailed characterization of the response and recovery times of the measurement system was used to deconvolve the true NH3 signal from the remaining adsorption-induced hysteresis. Parallel measurements with an aerosol mass spectrometer were used to correct the observed NH3 for the contribution of ammonium nitrate, which completely evaporated in the heated line at the chosen temperature, in contrast to ammonium sulfate. In this way a quantitative measurement of ambient gaseous NH3 was achieved with sufficient time resolution to enable measurement of NH3 point sources with a mobile sampling platform. The NH3 analyzer and the aerosol mass spectrometer were complemented by an aethalometer and various gas-phase analyzers to enable a complete characterization of the sources of air pollution, including the spatial distributions and the regional background concentrations and urban increments of all measured components. Although at all three locations similar increment levels of organic aerosols were attributed to biomass burning and traffic, traffic emissions clearly dominated the city enhancements of NH3, equivalent black carbon (eBC) and carbon dioxide (CO2). Urban increments of 3.4, 1.8 and 3.0 ppb of NH3 were measured in the traffic areas in Zurich, Tartu and Tallinn, respectively, representing an enhancement of 36.6, 38.3 and 93.8% over the average background concentrations. Measurements in areas strongly influenced by traffic emissions (including tunnel drives) were used to estimate emission factors (EF) for the traffic-related pollutants. The obtained median EFs range between 136.8-415.1 mg kg−1 fuel for NH3, 157.1–734.8 mg kg−1 fuel for eBC and 39.9–324.3 mg kg−1 fuel for HOA. Significant differences were found between the EFs of certain components in the three cities, which were partially linked to an older vehicle fleet in Estonia compared to Switzerland. Using the determined EFs we show that traffic can fully explain the NH3 enhancements in the three cities and also presents a non-negligible fraction of the background concentrations, which are mostly related to agricultural activities. Moreover, the estimated total contribution of traffic to NH3 at all three locations is in good agreement with the available emission inventories.

Small firearm shooting emits residues of energetic materials as well as heavy metals of different particle sizes into the air, posing a risk to human health. The current study assessed concentratio ...

This work describes results obtained from the 2016 Aerosol Chemical Speciation Monitor (ACSM) intercomparison exercise performed at the Aerosol Chemical Monitor Calibration Center (ACMCC, France). Fifteen quadrupole ACSMs (Q_ACSM) from the European Research Infrastructure for the observation of Aerosols, Clouds and Trace gases (ACTRIS) network were calibrated using a new procedure that acquires calibration data under the same operating conditions as those used during sampling and hence gets information representative of instrument performance. The new calibration procedure notably resulted in a decrease in the spread of the measured sulfate mass concentrations, improving the reproducibility of inorganic species measurements between ACSMs as well as the consistency with co-located independent instruments. Tested calibration procedures also allowed for the investigation of artifacts in individual instruments, such as the overestimation of m/z 44 from organic aerosol. This effect was quantified by the m/z (mass-to-charge) 44 to nitrate ratio measured during ammonium nitrate calibrations, with values ranging from 0.03 to 0.26, showing that it can be significant for some instruments. The fragmentation table correction previously proposed to account for this artifact was applied to the measurements acquired during this study. For some instruments (those with high artifacts), this fragmentation table adjustment led to an “overcorrection” of the f44 (m/z 44/Org) signal. This correction based on measurements made with pure NH4NO3, assumes that the magnitude of the artifact is independent of chemical composition. Using data acquired at different NH4NO3 mixing ratios (from solutions of NH4NO3 and (NH4)2SO4) we observe that the magnitude of the artifact varies as a function of composition. Here we applied an updated correction, dependent on the ambient NO3 mass fraction, which resulted in an improved agreement in organic signal among instruments. This work illustrates the benefits of integrating new calibration procedures and artifact corrections, but also highlights the benefits of these intercomparison exercises to continue to improve our knowledge of how these instruments operate, and assist us in interpreting atmospheric chemistry. © 2019, © 2019 Author(s). Published with license by Taylor & Francis Group, LLC., Funding text #1 aLaboratoire de Météorologie Physique (LaMP), Aubiere, France; bInstitut National de l’Environnement Industriel et des Risques (INERIS), Verneuil-en-Halatte, France; cLaboratoire des Sciences du Climat et de l’Environnement (LSCE), CNRS-CEA-UVSQ, Gif-sur-Yvette, France; dAerodyne Research, Inc, Billerica, Massachusetts, USA; eEnvironment Energy and Water Research Center, The Cyprus Institute, Nicosia, Cyprus; fEstonian Environmental Research Center (EERC), Tallinn, Estonia; gFinnish meteorological institute (FMI), Helsinki, Finland; hIERSD, National Observatory of Athens, Athens, Greece; iDepartment of the Environment, Centre for Energy, Environment and Technology Research (CIEMAT), Madrid, Spain; jDeutscher Wetterdienst, Meteorologisches Observatorium Hohenpeißenberg, Hohenpeißenberg, Germany; kInstitute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland; lLeibniz Institute for Tropospheric Research, Leipzig, Germany; mEnvironmental Research Group, MRC-HPA Centre for Environment and Health, King’s College London, London, United Kingdom; nInstitute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Spain; oLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland; pNational Institute of R&D for Optoelectronics (INOE), Ilfov, Romania; qProambiente S.c.r.l CNR Research Area, Bologna, Italy Funding text #2 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654109. The US Department of Energy Small Business Innovative Research program (award number DE-SC0017041) provided support for development of ACSM calibration procedures. CNRS, CEA, and INERIS are acknowledged for financial support of the ACMCC. The intercomparison campaign and the following data treatment have been conducted in collaboration with the French reference laboratory for air quality monitoring (LCSQA), funded by the French Ministry of Environment. COST action CA16109 Chemical On-Line cOmpoSition and Source Apportionment of fine aerosoLs COLOSSAL grant is gratefully acknowledged for the support of data workshops. M.C. Minguillón acknowledges the Ramón y Cajal fellowship awarded by the Spanish Ministry of Economy, Industry and Competitiveness. The CIEMAT participation has been partially funded by MINECO/AEI/FEDER, UE (CGL2017-85344-R and CGL2017-90884-REDT) and TIGAS-CM (Y2018/EMT- 5177) Project. PSI is grateful for financial support by the Federal Office for the Environment in Switzerland.

Bootstrap analysis is commonly used to capture the uncertainties of a bilinear receptor model such as the positive matrix factorization (PMF) model. This approach can estimate the factor-related uncertainties and partially assess the rotational ambiguity of the model. The selection of the environmentally plausible solutions, though, can be challenging, and a systematic approach to identify and sort the factors is needed. For this, comparison of the factors between each bootstrap run and the initial PMF output, as well as with externally determined markers, is crucial. As a result, certain solutions that exhibit suboptimal factor separation should be discarded. The retained solutions would then be used to test the robustness of the PMF output. Meanwhile, analysis of filter samples with the Aerodyne aerosol mass spectrometer and the application of PMF and bootstrap analysis on the bulk water-soluble organic aerosol mass spectra have provided insight into the source identification and their uncertainties. Here, we investigated a full yearly cycle of the sources of organic aerosol (OA) at three sites in Estonia: Tallinn (urban), Tartu (suburban) and Kohtla-Järve (KJ; industrial). We identified six OA sources and an inorganic dust factor. The primary OA types included biomass burning, dominant in winter in Tartu and accounting for 73 % ± 21 % of the total OA, primary biological OA which was abundant in Tartu and Tallinn in spring (21 % ± 8 % and 11 % ± 5 %, respectively), and two other primary OA types lower in mass. A sulfur-containing OA was related to road dust and tire abrasion which exhibited a rather stable yearly cycle, and an oil OA was connected to the oil shale industries in KJ prevailing at this site that comprises 36 % ± 14 % of the total OA in spring. The secondary OA sources were separated based on their seasonal behavior: a winter oxygenated OA dominated in winter (36 % ± 14 % for KJ, 25 % ± 9 % for Tallinn and 13 % ± 5 % for Tartu) and was correlated with benzoic and phthalic acid, implying an anthropogenic origin. A summer oxygenated OA was the main source of OA in summer at all sites (26 % ± 5 % in KJ, 41 % ± 7 % in Tallinn and 35 % ± 7 % in Tartu) and exhibited high correlations with oxidation products of a-pinene-like pinic acid and 3-methyl-1, 2, 3-butanetricarboxylic acid (MBTCA), suggesting a biogenic origin., Acknowledgements. This work was funded by the Estonian–Swiss cooperation program “Enforcement of the surveillance network of the Estonian air quality: Determination of origin of fine particles in Estonia”. María Cruz Minguillón acknowledges the Ramón y Ca-jal Fellowship awarded by the Spanish Ministry of Economy, Industry and Competitiveness. The Labex OSUG@2020 (ANR-10-LABX-56) provided the funding for part of the analytical equipment at Institut des Géosciences de l’Environnement (IGE; France). We also acknowledge the contribution of the COST Action CA16109 COLOSSAL.

Air pollution is one of the main environmental concerns in urban areas, where anthropogenic emissions strongly affect air quality. This work presents the first spatially resolved detailed characterization of PM2.5 (particulate matter with aerodynamic equivalent diameter daero ≤ 2.5 µm) in two major Estonian cities, Tallinn and Tartu. The measurements were performed in March 2014 using a mobile platform. In both cities, the non-refractory (NR)-PM2.5 was characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) using a recently developed lens which increases the transmission of super-micron particles. Equivalent black carbon (eBC) and several trace gases including carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were also measured. The chemical composition of PM2.5 was found to be very similar in the two cities. Organic aerosol (OA) constituted the largest fraction, explaining on average about 52 to 60 % of the PM2.5 mass. Four sources of OA were identified using positive matrix factorization (PMF): hydrocarbon-like OA (HOA, from traffic emissions), biomass burning OA (BBOA, from biomass combustion), residential influenced OA (RIOA, probably mostly from cooking processes with possible contributions from waste and coal burning), and oxygenated OA (OOA, related to secondary aerosol formation). OOA was the major OA source during nighttime, explaining on average half of the OA mass, while during daytime mobile measurements the OA was affected by point sources and dominated by the primary fraction. A strong increase in the secondary organic and inorganic components was observed during periods with transport of air masses from northern Germany, while the primary local emissions accumulated during periods with temperature inversions. Mobile measurements offered the identification of different source regions within the urban areas and the assessment of the extent to which pollutants concentrations exceeded regional background levels (urban increments). HOA, eBC, CO2, and CO showed stronger enhancements on busy roads during the morning and evening traffic rush hours; BBOA had its maximum enhancement in the residential areas during the evening hours and RIOA was enhanced in both the city center (emissions from restaurants) and in the residential areas (emissions from residential cooking). In contrast, secondary components (OOA, sulfate (SO4), nitrate (NO3), ammonium (NH4), and chloride (Cl)) had very homogeneous distributions in time and space. We were able to determine a total PM2.5 urban increment in Tartu of 6.0 µg m−3 over a regional background concentration of 4.0 µg m−3 (i.e., a factor of 2.5 increase). Traffic exhaust emissions were identified as the most important source of this increase, with eBC and HOA explaining on average 53.3 and 20.5 % of the total increment, respectively.

Waste burning is globally important emission source of several toxic compounds. The objective of this study was to acquire emission factors (EF) for PCDD/Fs, HCBs, PAHs, PMx and for several gaseous pollutants from the residential combustion, where wood is burned with municipal solid waste (MSW). In addition to the wood, paper and cardboard waste, people also tend to burn MSW. As the burnable waste content in MSW has changed during the past years, it is important to assess the effect of this factor for air emissions nowadays and in the past. Therefore an attempt was made to derive EF for the past emissions. 18 experiments including samples of firewood and MSW were burned using Estonian most common old type masonry heater, measuring PMx, PCDD/F, HCB, PAH-s and gaseous pollutants. Significant correlation was found between PCDD/F, HCl, HCB and CO and between HCl and HCB in all 18 experiments. In three experiments (years 1990, 1995, 2000), the mean levels of PCDD/F were higher than the legislative limit value for combustion of MSW in waste incineration plants. The mean PCDD/F concentrations during the experiments was 0.0833 (0.0116–0.1550 95% Cl) ng I-TEQ Nm −3 11% O 2 . Since low chlorine levels in used fuel caused high emissions of PCDD/F and HCB, it indicates that the habit of burning these kinds of waste in residential heaters should be avoided. We can conclude that RWC is significant source of PCDD/F, HCB and PAH. In general, EF measured within this study are in accordance with literature data. There was remarkable difference in EF between different years. EF of PCDD/F and HCB found confirm the trend of development of MSW collection system leading to an increasing usage of MSW recycling. Nevertheless, people's awareness about the negative impacts of waste burning in household heaters, should be raised.

Emissions from cattle farms in Estonia may vary from emissions in other regions of Europe due climatic differences and the housing systems used. Emission factors (EF) for the tie and loose housing systems for dairy farming were measured. Ammonia, odour and H2S emission measurements were made in tie and loose housing cattle farms with solid and liquid manure systems. Measurement were carried out in 2007 (10 different days from February to October) and in 2013 (in 30 different days in July–August). The gaseous EFs calculated for the tie housing cow building were 5.34 ± 0.47 kg [NH3] y−1 AU−1, 19.36 ± 4.39 g [H2S] y−1 AU−1 and for odour was 1.77 ± 3.06 OU y−1 AU−1. The EFs for the loose housing cow barn were 6.50 ± 4.01 kg [NH3] y−1 AU−1, 51.34 ± 30.34 g [H2S] y−1 AU−1 and for odour were 15.63 ± 20.96 OU y−1 AU−1. The NH3 and H2S EFs were validated through dispersion modelling against ambient levels measured in vicinity of the farms using passive samplers. An Eulerian advection-diffusion model with meteorological data was used to validate NH3 and H2S emission data. There was in general good correlation between measured and modelled levels for NH3 in both farms and for H2S in farm B. In general the EF were reliable and can be used in local and regional emission inventories and in dispersion calculations, but variation of emissions with temperature needs be taken into account. Further research is required to investigate emissions from more dairy farms over longer periods.

The concentration of airborne particulate matter in large scale uninsulated loose housing cowsheds was investigated. Airborne particulate matter can be a potential risk factor for human and animal health. Also investigated were correlations between indoor particulate matter, noxious gas concentrations and other microclimate parameters. Measures of inhalable particulate matter (PMtotal, PM10) and respirable particulate matter (PM2.5 and PM1.0), carbon dioxide (CO 2 ) and ammonia (NH 3 ) concentrations, air temperature, and relative humidity were taken at eight to 13 locations in nine large uninsulated loose housing cowsheds in Estonia from September 2008 to August 2009. The mean recorded concentrations of PMtotal were 205 ± 270 μg m −3 , PM10 65 ± 121 μg m −3 , PM2.5 18 ± 46 μg m −3 and PM1.0 10 ± 11 μg m −3 . The overall mean inside air CO 2 concentration was 553 ± 315 ppm, and that of ammonia 1.2 ± 1.9 ppm. The mean air temperature was 9.6 ± 6.6 °C, and relative humidity 83.2 ± 16.8%. The concentration of particulate matter (all fractions) inside the uninsulated loose housing cowsheds was low compared to pig and poultry housing systems. There was a clear seasonal variation between measurements in summer and winter. The particulate matter (all fractions) and CO 2 concentrations were higher, and ammonia concentrations lower, in the winter. The particulate matter concentration in the atmosphere also had an effect on the internal environment in uninsulated loose housing cowsheds.