Amodio, M., Andriani, E., Angiuli, L., Assennato, G., de Gennaro, G., Di Gilio, A., Giua, R., Intini M., Menegotto M., Nocioni, A., Palmisani, J., Perrone, M. R., Placentino, C. M. & Tutino, M. 2011: Chemical characterization of PM in the Apulia Region: local and long-range transport contributions to particulate matter. Boreal Env. Res. 16: 251–261.
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Salma, I., Borsós, T., Aalto, P. P. & Kulmala, M. 2011: Time-resolved number concentrations and size distribution of aerosol particles in an urban road tunnel. Boreal Env. Res. 16: 262–272.
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Maenhaut, W., Wang, W. & Chi, X. 2011: Semivolatile behaviour and filter sampling artifacts for dicarboxylic acids during summer campaigns at three forested sites in Europe. Boreal Env. Res. 16: 273–287.
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Liao, L., Dal Maso, M., Taipale, R., Rinne, J., Ehn, M., Junninen, H., Äijälä, M., Nieminen, T., Alekseychik, P., Hulkkonen, M., Worsnop, D. R., Kerminen, V.-M. & Kulmala, M. 2011: Monoterpene pollution episodes in a forest environment: indication of anthropogenic origin and association with aerosol particles. Boreal Env. Res. 16: 288–303.
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Paramonov, M., Grönholm, T. & Virkkula, A. 2011: Below-cloud scavenging of aerosol particles by snow at an urban site in Finland. Boreal Env. Res. 16: 304–320.
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Guenther, A., Kulmala, M., Turnipseed, A., Rinne, J., Suni, T. & Reissell, A. 2011: Integrated land ecosystem–atmosphere processes study (iLEAPS) assessment of global observational networks. Boreal Env. Res. 16: 321–336.
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Kulmala, M., Alekseychik, P., Paramonov, M., Laurila, T., Asmi, E., Arneth, A., Zilitinkevich, S. & Kerminen, V.-M. 2011: On measurements of aerosol particles and greenhouse gases in Siberia and future research needs. Boreal Env. Res. 16: 337–362.
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Amodio, M., Andriani, E., Angiuli, L., Assennato, G., de Gennaro, G., Di Gilio, A., Giua, R., Intini M., Menegotto M., Nocioni, A., Palmisani, J., Perrone, M. R., Placentino, C. M. & Tutino, M. 2011: Chemical characterization of PM in the Apulia Region: local and long-range transport contributions to particulate matter. Boreal Env. Res. 16: 251–261.

The chemical composition of PM₁₀ samples collected during a monitoring campaign performed at five Apulia Region sites (Torchiarolo, Galatina, Taranto-Tamburi, Palagiano and Montalbano-Ostuni) was investigated. Ionic fraction, metals, carbonaceous compounds and polycyclic aromatic hydrocarbons (PAHs) were determined for all samples. The PM concentrations showed a regional background of PM₁₀ at all the sites except for Taranto and Torchiarolo which are characterized by an important industrial area close to the town and by a local biomass burning source, respectively. A principal component analysis (PCA) applied to the dataset provided four sources relevant for the area under investigation, that were identified as combustion processes, crustal, marine aerosol and secondary particulate matter. The integrated approach used in this work (chemical characterization of the samples, meteorological information and statistical analysis) allowed to evaluate the synergistic effect of regional secondary particulate and long-transport contributions to PM₁₀ concentrations at the sampling sites and to provide useful information in order to characterize the most relevant local emission sources.

Salma, I., Borsós, T., Aalto, P. P. & Kulmala, M. 2011: Time-resolved number concentrations and size distribution of aerosol particles in an urban road tunnel. Boreal Env. Res. 16: 262–272.

We used flow-switching type differential mobility particle sizer in a diameter range of 6–1000 nm and vehicle counting detectors with a time resolution of 10 min for 15 days in July 2010 in the Castle District Tunnel, Budapest. The total particle number concentrations varied from 5.1 x 10³ to 465 x 10³ cm^–3 with a median of 143 x 10³ cm^–3. The median was greater by a factor of 12 than that for the urban ambient air. The mean (± SD) contribution of ultrafine particles to the total particle number was 85% ± 1%, which is significantly greater than for the urban ambient air. Diurnal variations in the number concentrations in the tunnel on workdays exhibited different time pattern than the traffic, which was explained by ventilation. Number size distributions of particles were resolved into Aitken and accumulation modes with the overall median diameters of 33 and 86 nm, respectively. The mean Aitken mode/accumulation mode concentration ratio was 3.6.

Maenhaut, W., Wang, W. & Chi, X. 2011: Semivolatile behaviour and filter sampling artifacts for dicarboxylic acids during summer campaigns at three forested sites in Europe. Boreal Env. Res. 16: 273–287.

The sampling artifacts for C₂–C₅ dicarboxylic acids (DCAs) were studied by collecting high-volume PM_2.5 samples using front and back quartz-fibre filters. The filters were analysed for carbonaceous components, and for inorganic cationic and anionic and organic anionic species. Back/front filter ratios were determined for the C₂–C₅ DCAs, but also for methanesulphonate (MSA^–), the various inorganic species, and the carbonaceous components. The sampling artifacts for the inorganic species were small (< 5%) with the exception of those for nitrate. The median back/front filter ratios for MSA^– and the C₂–C₅ DCAs increased in the following order: oxalate (1.5%)–succinate (3%)–MSA^– (4%)–malonate (2%–9%)–glutarate (7%–26%). Most of these ratios are smaller than those that were obtained for organic carbon, total carbon, and especially water-soluble organic carbon. Our back/front ratios for the C₂–C₅ DCAs are lower to much lower than those found in other studies.

Liao, L., Dal Maso, M., Taipale, R., Rinne, J., Ehn, M., Junninen, H., Äijälä, M., Nieminen, T., Alekseychik, P., Hulkkonen, M., Worsnop, D. R., Kerminen, V.-M. & Kulmala, M. 2011: Monoterpene pollution episodes in a forest environment: indication of anthropogenic origin and association with aerosol particles. Boreal Env. Res. 16: 288–303.

We used a monoterpene volume mixing ratio dataset measured from 12 June 2006 to 24 September 2007 and from 1 June 2008 to 3 March 2009 at the SMEAR II station to quantify the magnitude of anthropogenic monoterpene emissions aside from biogenic origins, to examine the anthropogenic sources, and to look at other associated pollutants. We discuss the relations between increased monoterpene mixing ratios and particle concentrations. We also characterize chemical properties of aerosol particles during two monoterpene pollution episodes in case studies. Out of 580 days analyzed, anthropogenic monoterpene pollution episodes were found on 341 (58.8%) days. The average monoterpene mixing ratio increased from 0.19 to 0.26 ppbv due to the presence of anthropogenic monoterpenes, which is equal to an increase of 36.8%. The observed anthropogenic monoterpenes were mostly from the Korkeakoski sawmill. Other gas pollutants might occasionally be emitted during the episodes, but did not show clear association with anthropogenic monoterpenes. Aerosol particle concentrations substantially increased during episodes, and monoterpene mixing ratios showed strong connections with Aitken mode particles both in number and volume concentrations. Particles associated with monoterpene episodes reached a CCN (cloud concentration nucleus) size. The chemical characterizations of aerosol particles in case studies show that the increase in aerosol particle mass was mainly from secondary organic aerosol.

Paramonov, M., Grönholm, T. & Virkkula, A. 2011: Below-cloud scavenging of aerosol particles by snow at an urban site in Finland. Boreal Env. Res. 16: 304–320.

Below-cloud scavenging of aerosol particles by snow is an important mechanism of wet deposition in mid-latitude, polar and mountainous regions. The study presents an analysis of below-cloud snow scavenging of aerosol particles in the 0.01–1 µm size range and 0.1–1.2 mm h^–1 snowfall rate range for an urban environment. The calculated mean scavenging coefficients were in good agreement with those previously reported for a rural background site in Finland. The variation of scavenging coefficients across the size distribution clearly exhibited a Greenfield gap for particles 0.06–0.3 µm in diameter. It was shown that snow is a better scavenger of aerosol particles than rain per equivalent water content. The relative humidity (RH) was deemed the most important meteorological parameter affecting the efficiency of snow scavenging, where an increase in the RH clearly resulted in an increase in below-cloud scavenging coefficient values. A new parameterization equation was developed for scavenging coefficients with respect to both particle diameter and relative humidity for snowfall intensities up to 1.2 mm h^–1.

Guenther, A., Kulmala, M., Turnipseed, A., Rinne, J., Suni, T. & Reissell, A. 2011: Integrated land ecosystem–atmosphere processes study (iLEAPS) assessment of global observational networks. Boreal Env. Res. 16: 321–336.

Long-term, continuous observations are needed for Earth system investigations and evaluation of simulations. The atmospheric and ecological communities have independently established field sites that have been running for many decades and are integrated into global networks. In the past decade, the importance of long-term observational networks focused on land ecosystem–atmosphere exchange, and the processes controlling land–atmosphere coupling, had been increasingly recognized and has led to the building of a global network of water, carbon and energy flux sites. This is an important step but further enhancements are necessary in order to quantify all of the land–atmosphere processes that need to be included in Earth system models. This paper describes the current land ecosystem–atmosphere measurement capabilities and presents the status and needs for global observational networks.

Kulmala, M., Alekseychik, P., Paramonov, M., Laurila, T., Asmi, E., Arneth, A., Zilitinkevich, S. & Kerminen, V.-M. 2011: On measurements of aerosol particles and greenhouse gases in Siberia and future research needs. Boreal Env. Res. 16: 337–362.

The role of the world’s boreal forest for our understanding of the climate system is indisputable. Due to the large area covered, the forest’s biophysical (e.g. surface energy balance, albedo) and biogeochemical (e.g. bidirectional exchange of greenhouse gases or aerosol precursors) processes are known to affect today's climate, and will need to be accounted for in studies of climate feedbacks in response to anthropogenic warming. However, observations that are needed to develop and evaluate terrestrial and climate models are still relatively scarce, especially for the Siberian part of the boreal forest. Here, we present a short overview of aerosol and greenhouse gas measurements over Siberia, aiming to also survey a large fraction of the existing literature in Russian. We aim to highlight areas of least data coverage and argue that, due to the importance of Siberia in the global climate system, a coordinated research program is needed to address some of the open research questions: The Pan Siberian Experiment.