AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Urban and Suburban Intermodal Fraction of Atmospheric Aerosol
JANA KOZAKOVA, Jan Hovorka, Jaroslav Schwarz, Charles University in Prague
Abstract Number: 224 Working Group: Urban Aerosols
Abstract Fine (PM1) and coarse (PM10-2.5) aerosols differ not only in size but in chemical composition and type of sources, among others. A clear separation between fine and coarse aerosol is obscurely defined. These fractions overlap in the aerodynamic particle size range 1-2.5 micro-meter, also called the intermodal fraction. Sources of both coarse and fine aerosols contribute to the intermodal fraction to a different extent relating to different meteorological conditions and types of location. The aim of this study was to characterize the intermodal fraction in urban and suburban localities and estimate to what extent fine/coarse aerosol sources contribute to this fraction.
We carried out a monthly measuring campaign in Ostrava city at an urban and a suburban site (Radvanice, Plesna) during winter 2014 and two 15-day campaigns in Prague (Benatska, Suchdol) during summer 2014 and winter 2015 in the Czech Republic. At all sites, five minute aerosol size distributions from 0.014-20 micrometers were recorded and daily samples of size resolved aerosol particles were sampled by Personal Cascade Impactor Sampler (PCIS).
The results from PCIS showed that the intermodal fraction represented an average mass range of 6-10% of the total PM10 in all locations. The highest average concentrations of coarse, intermodal and fine fraction (5, 4, 40 micrograms per cubic meter) were observed in the urban residential locality Radvanice situated near an industrial zone. In Ostrava, there was a similar ionic composition of the intermodal fraction with the coarse fraction observed at Radvanice, while the intermodal fraction was closer to the fine fraction at the Plesna site. In-depth aerosol source identification of the intermodal fraction will be conducted with the help of inductively coupled plasma mass spectrometry and scanning electron microscopy applied to aerosol samples.
The project is supported by the Czech Grant Agency (P503/12/G147) and Charles University Grant Agency (274213).