AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Intermodal Fraction of Particulate Matter in Indoor and Outdoor Microenvironments
MARTIN BRANIS, Jana Kozakova, Charles University in Prague, Faculty of Science
Abstract Number: 203 Working Group: Urban Aerosols
Abstract Coarse and fine particles overlap in a particle size interval between 1 and 2.5 micrometers. Since this interval appears between the accumulation and coarse mode it is called an intermodal fraction. Sources of both coarse and fine aerosols contribute to intermodal fraction to a certain extent and the contributions of individual sources may vary under different meteorological and/or spatial conditions. According to several studies, intermodal fraction correlates more with coarse aerosol during higher wind velocities and windstorms in arid regions. In contrast, other studies have shown ambiguous or different results. Concentrations of size-resolved particulate matter were monitored indoors and outdoors by a low volume cascade impactor during various seasons in different urban and rural locations. Multiple regression analysis with intermodal fraction as a dependent variable and coarse and fine aerosol, temperature, humidity, wind velocity as well as number of persons (indoors) as independent variables showed that generally, outdoor and indoor concentrations of the intermodal fraction were associated predominantly with coarse aerosol. Association between the intermodal and fine fraction was also documented, however, it was much lower than the above mentioned coarse-intermodal association. Future analysis will be focussed on chemical, mineralogical and morphological characteristics as well as the microclimatic conditions in order to find the various sources of this interesting fraction and ascertain the conditions which affect its formation.