Print Email Facebook Twitter Long-term observations of the background aerosol at Cabauw, The Netherlands Title Long-term observations of the background aerosol at Cabauw, The Netherlands Author Mamali, D. Mikkilä, J. Henzing, B. Spoor, R. Ehn, M. Petäjä, T. Russchenberg, H. Biskos, G. Publication year 2018 Abstract Long-term measurements of PM2.5 mass concentrations and aerosol particle size distributions from 2008 to 2015, as well as hygroscopicity measurements conducted over one year (2008–2009) at Cabauw, The Netherlands, are compiled here in order to provide a comprehensive dataset for understanding the trends and annual variabilities of the atmospheric aerosol in the region. PM2.5 concentrations have a mean value of 14.4 μg m-3 with standard deviation 2.1 μg m-3, and exhibit an overall decreasing trend of −0.74 μg m-3 year-1. The highest values are observed in winter and spring and are associated with a shallower boundary layer and lower precipitation, respectively, compared to the rest of the seasons. Number concentrations of particles smaller than 500 nm have a mean of 9.2 × 103particles cm-3 and standard deviation 4.9 × 103particles cm-3, exhibiting an increasing trend between 2008 and 2011 and a decreasing trend from 2013 to 2015. The particle number concentrations exhibit highest values in spring and summer (despite the increased precipitation) due to the high occurrence of nucleation-mode particles, which most likely are formed elsewhere and are transported to the observation station. Particle hygroscopicity measurements show that, independently of the air mass origin, the particles are mostly externally mixed with the more hydrophobic mode having a mean hygroscopic parameter κ of 0.1 while for the more hydrophilic mode κ is 0.35. The hygroscopicity of the smaller particles investigated in this work (i.e., particles having diameters of 35 nm) appears to increase during the course of the nucleation events, reflecting a change in the chemical composition of the particles. © 2017 Elsevier B.V. Subject 2015 Urban Mobility & EnvironmentCAS - Climate, Air and SustainabilityELSS - Earth, Life and Social SciencesEnvironment & SustainabilityEnvironmentUrbanisationAir pollutionAtmospheric particlesHTDMAPM2.5SMPS To reference this document use: http://resolver.tudelft.nl/uuid:38780b2c-c845-44e9-bc1d-d5a6e6209f3d DOI https://doi.org/10.1016/j.scitotenv.2017.12.136 TNO identifier 784882 ISSN 0048-9697 Source Science of the Total Environment, 625, 752-761 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.