Found 9983 publications. Showing page 99 of 400:
2019
Fatty alcohols. Anthropogenic and natural occurence in the environment. 2nd edition.
Royal Society of Chemistry (RSC)
2019
2019
This report presents VOC measurements carried out during 2017 at EMEP monitoring sites. In total, 20 sites reported VOC data from EMEP VOC sites this year. Some of the data sets are considered preliminary and are not included in the report. The monitoring of NMHC (non-methane hydrocarbons) has become more diverse with time in terms of instrumentation. Starting in the early 1990s with standardized methods based on manual sampling in steel canisters with subsequent analyses at the lab, the methods now consist of a variety of instruments and measurement principles, including automated continuous monitors and manual flask samples. For oxygenated VOCs (OVOCs), sampling in DNPH-tubes with subsequent labanalyses is still the only method in use at EMEP sites. Within the EU infrastructure project ACTRIS-2, data quality issues related to measurements of VOC have been an important topic. Many of the institutions providing VOC data to EMEP have participated in the ACTRIS-2 project, either as formal partners or on a voluntary basis. Participation in ACTRIS-2 has meant an extensive effort with data checking including detailed discussions between the ACTRIS community and individual participants. There is no doubt that this extensive effort has benefited the EMEP program and has led to improved data quality in general. Comparison between median levels in 2017 compared to the medians of the previous 10-years period, revealed a similar north-to-south pattern for several species. Changes in instrumentation, procedures, station network etc. during the last two decades make it difficult to provide a rigorous and pan-European assessment of long-term trends of the observed VOCs. In this report we have estimated the longterm trends in NMHC over the 2000-2017 period at six selected sites by two independent statistical methods. These estimates indicate marked differences in the trends for the individual species. Small or non-significant trends were found for ethane over this period followed by propane which also showed fairly small reductions. On the other hand, components linked to road traffic (ethene, ethyne and toluene) showed the strongest drop in mean concentrations, up to 60-80% at some stations. The trend in n-butane was between these two groups of species with an estimated drop in the annual mean concentration of 20-50% over the 2000-2017 period.
NILU
2019
In the framework of the EURODELTA-Trends (EDT) modeling experiment, several chemical transport models (CTMs) were applied for the 1990–2010 period to investigate air quality changes in Europe as well as the capability of the models to reproduce observed long-term air quality trends. Five CTMs have provided modeled air quality data for 21 continuous years in Europe using emission scenarios prepared by the International Institute for Applied Systems Analysis/Greenhouse Gas – Air Pollution Interactions and Synergies (IIASA/GAINS) and corresponding year-by-year meteorology derived from ERA-Interim global reanalysis. For this study, long-term observations of particle sulfate (SO2−4
), total nitrate (TNO3), total ammonium (TNHx) as well as sulfur dioxide (SO2) and nitrogen dioxide (NO2) for multiple sites in Europe were used to evaluate the model results. The trend analysis was performed for the full 21 years (referred to as PT) but also for two 11-year subperiods: 1990–2000 (referred to as P1) and 2000–2010 (referred to as P2).
The experiment revealed that the models were able to reproduce the faster decline in observed SO2 concentrations during the first decade, i.e., 1990–2000, with a 64 %–76 % mean relative reduction in SO2 concentrations indicated by the EDT experiment (range of all the models) versus an 82 % mean relative reduction in observed concentrations. During the second decade (P2), the models estimated a mean relative reduction in SO2 concentrations of about 34 %–54 %, which was also in line with that observed (47 %). Comparisons of observed and modeled NO2 trends revealed a mean relative decrease of 25 % and between 19 % and 23 % (range of all the models) during the P1 period, and 12 % and between 22 % and 26 % (range of all the models) during the P2 period, respectively.
Comparisons of observed and modeled trends in SO2−4
concentrations during the P1 period indicated that the models were able to reproduce the observed trends at most of the sites, with a 42 %–54 % mean relative reduction indicated by the EDT experiment (range of all models) versus a 57 % mean relative reduction in observed concentrations and with good performance also during the P2 and PT periods, even though all the models overpredicted the number of statistically significant decreasing trends during the P2 period. Moreover, especially during the P1 period, both modeled and observational data indicated smaller reductions in SO2−4
concentrations compared with their gas-phase precursor (i.e., SO2), which could be mainly attributed to increased oxidant levels and pH-dependent cloud chemistry.
An analysis of the trends in TNO3 concentrations indicated a 28 %–39 % and 29 % mean relative reduction in TNO3 concentrations for the full period for model data (range of all the models) and observations, respectively. Further analysis of the trends in modeled HNO3 and particle nitrate (NO−3
) concentrations revealed that the relative reduction in HNO3 was larger than that for NO−3 during the P1 period, which was mainly attributed to an increased availability of “free ammonia”. By contrast, trends in modeled HNO3 and NO−3 concentrations were more comparable during the P2 period. Also, trends of TNHx concentrations were, in general, underpredicted by all models, with worse performance for the P1 period than for P2. Trends in modeled anthropogenic and biogenic secondary organic aerosol (ASOA and BSOA) concentrations together with the trends in available emissions of biogenic volatile organic compounds (BVOCs) were also investigated. A strong decrease in ASOA was indicated by all the models, following the reduction in anthropogenic non-methane VOC (NMVOC) precursors. Biogenic emission data...
2019
2019
Monitoring of environmental contaminants in air and precipitation, annual report 2018
This report presents environmental monitoring data from 2018 and time-trends for the Norwegian programme for Long-range atmospheric transported contaminants. The results cover 200
organic compounds (regulated and non-regulated), 11 heavy metals, and organic chemicals of potential Arctic concern.
NILU
2019
The aim of this work was to assess how improvements to the indoor environment could affect the future condition, frequency and costs of major conservation-cleaning campaigns on the monumental paintings (1909–1916) by Edvard Munch, centrally located in the Aula assembly hall of the University of Oslo. A lower soiling rate is expected to reduce the need for frequent and major cleaning campaigns. Estimations were performed using the freely available NILU-EnvCul web-model. The conservation of these large, mostly unvarnished, oil paintings is challenging, and it is important to understand the potential benefits of preventive conservation measures. The results from the model suggested benefits from preventive conservation in protecting the paintings, and as a cost-efficient strategy to reduce the soiling and cleaning frequency. The model results indicated that an improvement in the indoor air quality in the Aula, of 50–80% as compared to the 1916–2009 average, would increase the time until the next similar major conservation cleaning campaign from approximately 45 years to between about 85 and 165 years. This should give a 45–70% reduction in the respective conservation costs. This saving was probably initiated by improvements in the recent past, before the last Aula campaign in 2009–11.
2019
Målet med studien er å vurdere effekten av tilskudd til utskifting av gamle vedovner til nye rentbrennende ovner, og i hvilken grad ordningen har påvirket det totale partikkelutslippet og luftkonsentrasjoner i Oslo kommune. NILU har utført tre beregninger; 1) utslippsmodellering og spredningsberegninger for 4 ulike scenarioer; 2) utslippsreduksjon fra tilskuddsordningen i Oslo kommune; og 3) vurdering av tidsutvikling av vedfyringsutslipp, vedforbruk og utslippsfaktorer for kommuner med og uten tilskuddsordning. Modellering og vurdering av den potensielle utslippsreduksjonen som kan tilskrives tilskuddsordningen, viser at tilskuddsordningen potensielt har en stor effekt på reduksjon av partikkelutslipp og konsentrasjoner av PM2.5 og PM10. Beregnigene viser at tilskuddsordningen i Oslo kommune gir betydelig redusert utslippsfaktor over tid, men effekten på totalt PM-utslipp er liten.
NILU
2019
2019
Air quality in Europe — 2019 report
This report presents an updated overview and analysis of air quality in Europe from 2000 to 2017. It reviews the progress made towards meeting the air quality standards established in the two EU Ambient Air Quality Directives and towards the World Health Organization (WHO) air quality guidelines (AQGs). It also presents the latest findings and estimates of population and ecosystem exposure to the air pollutants with the greatest impacts.
Publications Office of the European Union
2019
2019
The Mineral Aerosol Profiling from Infrared Radiances (MAPIR) algorithm retrieves vertical dust concentration profiles from cloud-free Infrared Atmospheric Sounding Interferometer (IASI) thermal infrared (TIR) radiances using Rodgers' optimal estimation method (OEM). We describe the new version 4.1 and evaluation results. Main differences with respect to previous versions are the Levenberg–Marquardt modification of the OEM, the use of the logarithm of the concentration in the retrieval and the use of Radiative Transfer for TOVS (RTTOV) for in-line radiative transfer calculations. The dust aerosol concentrations are retrieved in seven 1 km thick layers centered at 0.5 to 6.5 km. A global data set of the daily dust distribution was generated with MAPIR v4.1 covering September 2007 to June 2018, with further extensions planned every 6 months. The post-retrieval quality filters reject about 16 % of the retrievals, a huge improvement with respect to the previous versions in which up to 40 % of the retrievals were of bad quality. The median difference between the observed and fitted spectra of the good-quality retrievals is 0.32 K, with lower values over oceans. The information content of the retrieved profiles shows a dependence on the total aerosol load due to the assumption of a lognormal state vector. The median degrees of freedom in dusty scenes (min 10 µm AOD of 0.5) is 1.4. An evaluation of the aerosol optical depth (AOD) obtained from the integrated MAPIR v4.1 profiles was performed against 72 AErosol RObotic NETwork (AERONET) stations. The MAPIR AOD correlates well with the ground-based data, with a mean correlation coefficient of 0.66 and values as high as 0.88. Overall, there is a mean AOD (550 nm) positive bias of only 0.04 with respect to AERONET, which is an extremely good result. The previous versions of MAPIR were known to largely overestimate AOD (about 0.28 for v3). A second evaluation exercise was performed comparing the mean aerosol layer altitude from MAPIR with the mean dust altitude from Cloud–Aerosol LIdar with Orthogonal Polarization (CALIOP). A small underestimation was found, with a mean difference of about 350 m (standard deviation of about 1 km) with respect to the CALIOP cumulative extinction altitude, which is again considered very good as the vertical resolution of MAPIR is 1 km. In the comparisons against AERONET and CALIOP, a dependence of MAPIR on the quality of the temperature profiles used in the retrieval is observed. Finally, a qualitative comparison of dust aerosol concentration profiles was done against lidar measurements from two ground-based stations (M'Bour and Al Dhaid) and from the Cloud–Aerosol Transport System (CATS) instrument on board the International Space Station (ISS). MAPIR v4.1 showed the ability to detect dust plumes at the same time and with a similar extent as the lidar instruments. This new MAPIR version shows a great improvement of the accuracy of the aerosol profile retrievals with respect to previous versions, especially so for the integrated AOD. It now offers a unique 3-D dust data set, which can be used to gain more insight into the transport and emission processes of mineral dust aerosols.
2019
2019
Recent Trends in Maintenance Costs for Façades Due to Air Pollution in the Oslo Quadrature, Norway
This study assesses changes since 1980 in the maintenance cost of the façades of the historical 17th to 19th century buildings of the Oslo Quadrature, Norway, due to atmospheric chemical wear, including the influence of air pollution. Bottom up estimations by exposure–response functions for an SO2 dominated situation reported in the literature for 1979 and 1995 were compared with calculations for the present (2002–2014) multi-pollutant situation. The present maintenance cost, relative to the total façade area, due to atmospheric wear and soiling was found to be about 1.6 Euro/m2 per year. The exposure to local air pollution, mainly particulate matter and NOx gases, contributed to 0.6 Euro/m2 (38%), of which the cost due to wear of renderings was about 0.4 Euro/m2 (22%), that due to the cleaning of glass was 0.2 Euro/m2 (11%), and that due to wear of other façade materials was 0.07 Euro/m2 (5%). The maintenance cost due to the atmospheric wear was found to be about 3.5%, and that due to the local air pollution about 1.1% of the total municipal building maintenance costs. The present (2002–2014) maintenance costs, relative to the areas of the specific materials, due to atmospheric wear are probably the highest for painted steel surfaces, about 8–10 Euro/m2, then about 2 Euro/m2 for façade cleaning and the maintenance of rendering, and down to 0.3 Euro/m2 for the maintenance of copper roofs. These costs should be adjusted with the importance of the wear relative to other reasons for the façade maintenance.
2019
2019