Particle collection characteristics of the compressible flow stages 1–6 of the Berner low-pressure impactor (BLPI, Hauke Aeras 25-4/0.015) have been studied. A new, real-time impactor stage efficiency measurement system has been developed. It is based on the use of two electrometers, one connected to the collection plate of the impactor, and the other to the backup filter. This method is used with singly charged, monodisperse dioctyl phthalate (DOP) particles to determine the shape of the collection efficiency curves of the BLPI. In addition, particle collection characteristics have been studied using fluorometric analysis. A new method for substrate film greasing is also introduced. Experimental cut diameters of stages 1–6, as determined with DOP particles using electrical measurement method, are 0.034, 0.066, 0.094, 0.17, 0.33, and 0.55 /un. They are clearly larger than corresponding values given by the manufacturer. The average of the square root of the Stokes number at 50% collection efficiency, based...

https://www.tandfonline.com/doi/pdf/10.1080/02786829108959469

On the Performance of the Berner Low Pressure Impactor

A major fraction of fine particle matter consists of organic carbon (OC) but its origin is still inadequately known. In this study the sources of OC were investigated in the northern European urban environment in Helsinki, Finland. Measurements were carried out over one year and they included both filter (PM 1 ) and online methods. From the filter samples OC, elemental carbon (EC), water-soluble OC (WSOC), levoglucosan and major ions were analyzed. Filter data together with the concentrations of inorganic gases were analyzed by Positive matrix factorization (PMF) in order to find the sources of OC (and WSOC) on an annual as well as on a seasonal basis. In order to study the diurnal variation of sources, OC and EC were measured by a semicontinuous OC/EC analyzer and major ions were determined by a Particle-into-Liquid Sampler coupled to ion chromatographs. According to PMF, OC concentrations were impacted by four sources: biomass combustion, traffic, long-range transport and secondary production. On an annual basis the OC concentration was dominated by secondary organic aerosol (SOA). Its contribution to OC was as high as 64% in summer, which besides anthropogenic sources may also result from the large biogenic volatile organic carbon (VOC) emissions in the boreal region. In winter biomass combustion constituted the largest fraction in OC due to domestic wood combustion for heating purposes. Traffic contributed to OC from 15 to 27%. Regarding the diurnal variation, the contribution from traffic was higher from 08:00 to 18:00 on weekdays than on weekends. The contribution from long-range transport to OC was 24% on average. All four sources also influenced the WSOC concentrations, however, the contribution of SOA was significantly larger for WSOC than OC.

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Sources of organic carbon in fine particulate matter in northern European urban air

Sources and chemical composition of atmospheric fine and coarse particles in the helsinki area

http://netfam.fmi.fi/YSSS08/ATMENV-S-06-01459.pdf

Chemical composition of aerosols during a major biomass burning episode over northern Europe in spring 2006: Experimental and modelling assessments

The predominant peak in the mass distribution emitted from each source measured in this study occurs at or below about 0.2 μm in particle diameter, whereas the Los Angeles atmospheric aerosol contains peaks at a variety of sizes in the range between 0.1 and 1.0 μm in particle diameter, including peaks at sizes larger than 0.2 μm. This suggests that considerable modification of the primary aerosol size distribution occurs because of subsequent processes in the atmosphere. The data presented here are intended for use in defining the size distribution of the primary combustion source effluent for use with mathematical models of the evolution of the atmospheric aerosol size distribution.

https://www.tandfonline.com/doi/pdf/10.1080/02786829108959478

Axel Berner

Papers

Mass size distributions of traffic aerosols at Vienna