Number Concentrations and Modal Structure of Indoor/Outdoor Fine Particles in Four European Cities

Indoor/outdoor aerosol size distribution was measured in four European cities (Oslo-Norway, Prague-Czech Republic, Milan-Italy and Athens-Greece) during 2002 in order to examine the differences in the characteristics of the indoor/outdoor modal structure and to evaluate the effect of indoor sources to the aerosol size distributions. All the measurement sites were naturally ventilated and were occupied during the campaigns by permanent residents or for certain time periods by the technical staff responsible for the instrumentation. Outdoor particle number (PN) concentrations presented the higher values in Milan and Athens (median values 1.4 x 10(4) # cm(-3) and 2.9 x 10(4) # cm(-3) respectively) as a result of elevated outdoor emissions and led to correspondingly higher indoor values compared to Oslo and Prague. In absence of indoor activities, the indoor concentrations followed the fluctuations of the outdoor concentrations in all the measurement sites. Indoor activities (cooking, smoking, etc.) resulted in elevated indoor PN concentrations (maximum values ranging between 1.7 x 10(5) # cm(-3) and 3.2 x 10(5) # cm(-3)) and to I/O ratios higher than one. The I/O ratios were size dependant and for periods without indoor activities, they presented the lowest values for particles <50 nm (0.51 +/- 0.15) and the ratios increased with fine particle size (0.79 +/- 0.12 for particles between 100-200 nm). The analysis of the modal structure showed that the indoor aerosol size distribution characteristics differ from the outdoors under the effect of indoor sources. The percentage of unimodal size distributions increased during indoor emissions, compared to periods without indoor sources, along with the number concentration of Aitken mode particles, indicating emissions in specific size ranges according to the type of the indoor source.Peer reviewe

Reversal of Long-Term Trends in Ethane Identified from the Global Atmosphere Watch Reactive Gases Measurement Network

Reactive gases play an important role in climate and air pollution issues. They control the self-cleansing capability of the troposphere, contribute to air pollution and acid deposition, regulate the lifetimes and provide tracers for deciphering sources and sinks for greenhouse gases. Within GAW, the focus is placed on long-term, high-quality observations of ozone (O3), carbon monoxide (CO), volatile organic compounds (VOC), nitrogen oxides (NOx), and sulfur dioxide (SO2). More than 100 stations worldwide carry out reactive gases measurements with data reported to two World Data Centers. The reactive gases program in GAW cooperates The WMO GAW Reactive Gases Program with regional networks and other global monitoring initiatives in order to attain a complete picture of the tropospheric chemical composition. Observations are being made by in-situ monitoring, measurements from commercial routine air-crafts (e.g. IAGOS), column observations, and from flask sampling networks. Quality control and coordination of measurements between participating stations are a primary emphasis. GAW reactive gases data in rapid delivery mode are used to evaluate operational atmospheric composition forecasts in the EU Copernicus Atmospheric Monitoring Service. Oversight of the program is provided by GAW-WMO coordinated Reactive Gases Scientific Advisory Committee (RG-SAG)

Air pollution trends in the EMEP region between 1990 and 2012

The present report synthesises the main features of the evolution over the 1990-2012 time period of the concentration and deposition of air pollutants relevant in the context of the Convention on Long-range Transboundary Air Pollution: (i) ozone, (ii) sulfur and nitrogen compounds and particulate matter, (iii) heavy metals and persistent organic pollutants. It is based on observations gathered in State Parties to the Convention within the EMEP monitoring network of regional background stations, as well as relevant modelling initiatives. Joint Report of: EMEP Task Force on Measurements and Modelling (TFMM), Chemical Co-ordinating Centre (CCC), Meteorological Synthesizing Centre-East (MSC-E), Meteorological Synthesizing Centre-West (MSC-W)

Base cations deposition in Europe

The support from the Nordic Council of Ministers, the Working Group for Air and Sea Pollution, has significantly contributed to the development of unified calculations of base cation deposition across Europe with the EMEP model. Previous estimates of base cation deposition in Europe have mainly been based on empirical approaches of varying quality depending on country. The results of the model calculations will be used by CLRTAP and EU to assess the need for reduction of emissions of acidifying air pollutants in agreement with the Gothenburg protocol and NEC. The EMEP model has been extended to calculate the deposition of four base cations; calcium (Ca2+), magnesium (Mg2+), potassium (K+) and sodium (Na+). Natural emissions (from sea salt and wind blown dust) as well as anthropogenic emissions (from combustion and industrial processes) have been considered. Base cations are assumed to behave in a similar manner as primary particles in the atmosphere, and hence the transport and deposition of base cations are considered in the same way as primary particles in the EMEP model. The result of the EMEP modelling was compared with wet deposition fluxes derived from the EMEP and ICP-Forest network, and throughfall measurements from the ICP-Forest network, to assess the robustness of the model calculations. This comparison showed encouraging results. However, it was recognised that the EMEP model can be developed further, particularly regarding the estimates of base cation sources, to correctly quantify the base cation deposition in Europe. Furthermore, to provide a confident assessment of the results of the EMEP model, it is of great importance to further develop and improve the measurement methodologies and the methods applied to estimate dry deposition.The support from the Nordic Council of Ministers, the Working Group for Air and Sea Pollution, has significantly contributed to the development of unified calculations of base cation deposition across Europe with the EMEP model. Previous estimates of base cation deposition in Europe have mainly been based on empirical approaches of varying quality depending on country. The results of the model calculations will be used by CLRTAP and EU to assess the need for reduction of emissions of acidifying air pollutants in agreement with the Gothenburg protocol and NEC. The EMEP model has been extended to calculate the deposition of four base cations; calcium (Ca2+), magnesium (Mg2+), potassium (K+) and sodium (Na+). Natural emissions (from sea salt and wind blown dust) as well as anthropogenic emissions (from combustion and industrial processes) have been considered. Base cations are assumed to behave in a similar manner as primary particles in the atmosphere, and hence the transport and deposition of base cations are considered in the same way as primary particles in the EMEP model. The result of the EMEP modelling was compared with wet deposition fluxes derived from the EMEP and ICP-Forest network, and throughfall measurements from the ICP-Forest network, to assess the robustness of the model calculations. This comparison showed encouraging results. However, it was recognised that the EMEP model can be developed further, particularly regarding the estimates of base cation sources, to correctly quantify the base cation deposition in Europe. Furthermore, to provide a confident assessment of the results of the EMEP model, it is of great importance to further develop and improve the measurement methodologies and the methods applied to estimate dry deposition

Indirect evidence of the composition of nucleation mode atmospheric particles in the high Arctic

Previous long-term observations have shown that nanoparticle formation events are common in the summer-time high Arctic and linked to local photochemical activity. However, current knowledge is limited with respect to the chemical precursors of resulting nanoparticles and the compounds involved in their subsequent growth. Here we report case-study measurements during new particle formation (NPF) events of the particle size distribution (diameter &gt; 7 nm) and for the first time the volatility of monodisperse particles having diameter ≤40 nm, providing indirect information about their composition. Volatility measurements provide indirect evidence that a predominant fraction of the 12 nm particle population is ammoniated sulfates in the summertime high Arctic. Our observations further suggest that the majority of the sub-40 nm particle population during NPF events does not exist in the form of sulfuric acid but rather as partly or fully neutralized ammoniated sulfates.Atmospheric Remote Sensin

Determination of time- and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: the 2010 Eyjafjallajokull eruption

The April-May, 2010 volcanic eruptions of Eyjafjallajokull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that large improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 +/- 4.2 Tg for particles in the size range of 2.8-28 mu m diameter. We evaluate the results of our model results with a posteriori ash emissions using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "Normal" flying zone in up to 14% (6-16%), 2% (1-3%) and 7% (4-11%), respectively, of the European area. For a limit of 2 mg m(-3) only two episodes with fractions of 1.5% (0.2-2.8%) and 0.9% (0.1-1.6%) occurred, while the current "No-Fly" zone criterion of 4 mg m(-3) was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

New Directions: The future of European urban air quality monitoring

Air quality, especially in urban areas, deteriorated with the industrial revolution and the following centuries. It is only during the last 60 years, following e.g. the infamous London smog (1952), that the health impacts of air pollution have been recognised and acted upon. In the developed world, abatement strategies and closure of major industries have led to significant air quality improvements (Harrison, 2004; Lamarque et al., 2010; Monks et al., 2009; Smith et al., 2011). Even so, the evaluation of current research within the Clean Air for Europe (CAFE) process has clearly shown that, even today, investments in further air quality improvements will have a beneficial return financially, in terms of population health, environmental improvements and in quality of life (EEA, 2007; Stern, 2006). The measurement of air quality changed dramatically during the last century reflecting the concurrent knowledge about the adverse effects of air pollution, as well as the technological developments. The earliest measurement methods were often labour intensive, needed long analysis times and had a low time resolution. Routine measurements of air quality can be traced back to the Montsouris Manuscript Click here to download Manuscript: AMT_AtmosEnv_NewDirection_19_09_2013.docx Click here to view linked References 2 Observatory in Paris, where ozone was measured between 1876 and 1910 (Volz and Kley, 1988). Since then, scientists have pursued the concept of making measurements of air pollutants at fixed monitoring sites using well established, calibrated and comparable methods. Developments in air quality monitoring techniques during the second half of the 20th century enabled higher data quality to be obtained, with lower detection limits, using automated, continuous methods. One of the first real-time measurement techniques was initially developed by Fowler as early as 1949 for the measurement of e.g. CO2 (Keeling, 1960). Developments in online air quality monitoring enabled the development of public warning systems and immediate notifications if alert thresholds were exceeded. Short-term measures could then be taken to reduce emissions during pollution episodes. Measures included traffic reductions and closure of industrial facilities during e.g. winter smog episodes in Germany in the early 80’s (Bruckmann et al., 1986). Such reactive measures are now commonplace in new legislation (EC Directive, 2008; CFR 40, 2011; JAPC, 2011), along with public information to help vulnerable people to cope with pollution episodes (Kelly et al., 2012).JRC.H.2-Air and Climat