@article{SchneidemesserSibiyaCaseiroetal.2021,
  author    = {Schneidemesser, Erika von and Sibiya, Bheki and Caseiro, Alexandre and Butler, Tim and Lawrence, Mark and Leitao, Joana and Lupa{\c{s}}cu, Aura and Salvador, Pedro},
  title     = {Learning from the COVID-19 lockdown in Berlin},
  series = {Atmospheric environment: X},
  volume    = {12},
  journal   = {Atmospheric environment: X},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2590-1621},
  doi       = {10.1016/j.aeaoa.2021.100122},
  pages     = {13},
  year      = {2021},
  abstract  = {Urban air pollution is a substantial threat to human health. Traffic emissions remain a large contributor to air pollution in urban areas. The mobility restrictions put in place in response to the COVID-19 pandemic provided a large-scale real-world experiment that allows for the evaluation of changes in traffic emissions and the corresponding changes in air quality. Here we use observational data, as well as modelling, to analyse changes in nitrogen dioxide, ozone, and particulate matter resulting from the COVID-19 restrictions at the height of the lockdown period in Spring of 2020. Accounting for the influence of meteorology on air quality, we found that reduction of ca. 30-50 \% in traffic counts, dominated by changes in passenger cars, corresponded to reductions in median observed nitrogen dioxide concentrations of ca. 40 \% (traffic and urban background locations) and a ca. 22 \% increase in ozone (urban background locations) during weekdays. Lesser reductions in nitrogen dioxide concentrations were observed at urban background stations at weekends, and no change in ozone was observed. The modelled reductions in median nitrogen dioxide at urban background locations were smaller than the observed reductions and the change was not significant. The model results showed no significant change in ozone on weekdays or weekends. The lack of a simulated weekday/weekend effect is consistent with previous work suggesting that NOx emissions from traffic could be significantly underestimated in European cities by models. These results indicate the potential for improvements in air quality due to policies for reducing traffic, along with the scale of reductions that would be needed to result in meaningful changes in air quality if a transition to sustainable mobility is to be seriously considered. They also confirm once more the highly relevant role of traffic for air quality in urban areas.},
  language  = {en}
}
@article{AichnerBussianLehnikHabrinketal.2015,
  author    = {Aichner, Bernhard and Bussian, Bernd M. and Lehnik-Habrink, Petra and Hein, Sebastian},
  title     = {Regionalized concentrations and fingerprints of polycyclic aromatic hydrocarbons (PAHs) in German forest soils},
  series = {Environmental pollution},
  volume    = {203},
  journal   = {Environmental pollution},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0269-7491},
  doi       = {10.1016/j.envpol.2015.03.026},
  pages     = {31 -- 39},
  year      = {2015},
  abstract  = {Samples of 474 forest stands in Germany were analysed for concentrations of polycyclic aromatic hydrocarbons (PAHs) in three sampling depths. Enhanced concentrations were mainly found at spots relatively close to densely industrialized and urbanized regions and at some topographically elevated areas. Average enrichment factors between mineral soil and humic layer depend on humus type i.e. decrease from mull via moder to more Based on their compound-patterns, the observed samples could be assigned to three main clusters. For some parts of our study area a uniform assignment of samples to clusters over larger regions could be identified. For instance, samples taken at vicinity to brown-coal strip-mining districts are characterized by high relative abundances of low-molecular-weight PAHs. These results suggest that PAHs are more likely originated from local and regional emitters rather than from long-range transport and that specific source-regions can be identified based on PAH fingerprints. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}