AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Urban and Suburban Intermodal Fraction of Atmospheric Aerosol in Winter 2014
JANA KOZAKOVA, Jan Hovorka, Jaroslav Schwarz, Charles University in Prague
Abstract Number: 85 Working Group: Urban Aerosols
Abstract Fine (PM1) and coarse (PM10-2.5) aerosols differ not only in size but in chemical composition, health effects, type of sources and others. A dividing line between fine and coarse aerosol is not clearly defined. These fractions overlap in the aerodynamic particle size range 1-2.5 micrometers, 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 locations. According to several studies, the intermodal fraction highly correlated with coarse aerosol in dry areas during high wind speed episodes. In contrast, other studies have shown higher or comparable correlation with fine aerosol. The aim of this study was to characterize the intermodal fraction in urban and suburban localities and estimate at what extent fine/coarse aerosol sources contribute to this fraction. Measuring campaign took place from 5.2.-7.3.2014 at urban and suburban locality situated up-wind of the Ostrava city. At both sites, five minute integrates of aerosol size distribution from 0.524-20 micrometers were determined and daily samples of size resolved aerosol particles were sampled by Personal Cascade Impactor Sampler (PCIS) and Berner Low Pressure Impactor (BLPI).The results from PCIS showed that the intermodal fraction represented mass range 3-31% of the total PM10 in both locations with higher mass range in the suburban locality. Average concentrations of coarse, intermodal and fine fraction are 5.1, 3.5 and 40.4 micrograms per cubic meter in urban locality and 2.4, 3.8 and 32.0 micrograms per cubic meter in suburban locality. In-depth aerosol source identification to the intermodal fraction will be conducted with the help of ion chromatography (IC), inductively coupled plasma mass spectrometry (ICP-MS) and transmission electron microscopy (TEM) applied to aerosol samples.
The project is supported by the Czech Grant Agency (P503/12/G147) and the Charles University Grant Agency (274213).