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2019
2019
2019
2019
Europe's urban air quality — re-assessing implementation challenges in cities
European Environment Agency
2019
2019
Two years of continuous in situ measurements of Arctic low‐level clouds have been made at the Mount Zeppelin Observatory (78°56′N, 11°53′E), in Ny‐Ålesund, Spitsbergen. The monthly median value of the cloud particle number concentration (Nc) showed a clear seasonal variation: Its maximum appeared in May–July (65 ± 8 cm−3), and it remained low between October and March (8 ± 7 cm−3). At temperatures warmer than 0 °C, a clear correlation was found between the hourly Nc values and the number concentrations of aerosols with dry diameters larger than 70 nm (N70), which are proxies for cloud condensation nuclei (CCN). When clouds were detected at temperatures colder than 0 °C, some of the data followed the summertime Nc to N70 relationship, while other data showed systematically lower Nc values. The lidar‐derived depolarization ratios suggested that the former (CCN‐controlled) and latter (CCN‐uncontrolled) data generally corresponded to clouds consisting of supercooled water droplets and those containing ice particles, respectively. The CCN‐controlled data persistently appeared throughout the year at Zeppelin. The aerosol‐cloud interaction index (ACI = dlnNc/(3dlnN70)) for the CCN‐controlled data showed high sensitivities to aerosols both in the summer (clean air) and winter–spring (Arctic haze) seasons (0.22 ± 0.03 and 0.25 ± 0.02, respectively). The air parcel model calculations generally reproduced these values. The threshold diameters of aerosol activation (Dact), which account for the Nc of the CCN‐controlled data, were as low as 30–50 nm when N70 was less than 30 cm−3, suggesting that new particle formation can affect Arctic cloud microphysics.
American Geophysical Union (AGU)
2019
2019
2019
Air quality assessment and management in Europe and Norway: History, current status and future plans
2019
2019
2019
2019
Norwegian Scientific Committee for Food and Environment (VKM)
2019
The aim of the study is to assess the effect of the subsidy to replace old wood stoves for new clean burning stoves, and to what extent the scheme has influenced the total particle emissions and pollution concentrations in Oslo municipality. NILU selected three methods; 1) emission and dispersion modelling for 4 different scenarios; 2) estimate the emission reduction associated with the subsidy scheme in Oslo municipality; and 3) a comparison of changes in emissions, wood consumption and emission factors over time in municipalities with and without subsidy. Modeling and assessment of the potential emission reduction associated with the subsidy scheme shows that it has a potentially significant effect on the reduction of particulate emissions and concentrations of PM2.5 and PM10. The estimates show that the subsidy scheme in Oslo municipality gives a significant reduction in average emission factor over time. However, the effect on total PM-emissions is small.
NILU
2019
2019