2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
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Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology<br />
P69 ThE EPR STuDy OF PARTICuLATE MATTER<br />
nADEŽDA ŠTEVULOVá, ADRIAnA EŠTOKOVá and<br />
PAVeL STOPKA<br />
Technical University of Košice, Civil Engineering Faculty,<br />
Institute of Building and Environmental Engineering, Vysokoškolská<br />
4, 042 00 Košice, Slovak Republic,<br />
Nadezda.Stevulova@tuke.sk<br />
Introduction<br />
In recent years the role of particulate matter in environmental<br />
and health areas has come under increased attention<br />
of experts and public. The PM 10 and PM <strong>2.</strong>5 (particle fractions<br />
related to their size) concentrations show higher correlation to<br />
the negative health effects in comparison to the total suspended<br />
particulate matter 1 . Building constructions and materials<br />
play an important role in indoor particulate matter contamination<br />
due to particles infiltration through joint construction<br />
leakages and material distribution and deposition processes 2 .<br />
The dust particles are dangerous not only because of<br />
their high concentrations in dependence on their particle size<br />
but also because of their nature 3 . The surface of the inhaled<br />
particles which determines the biological response is large.<br />
The surface reactivity of particles depends on the number of<br />
reactive spots on the dust particles surface and on the distribution<br />
of various sites (free radicals and paramagnetic species)<br />
at the surface 4 . It determines the pathogenic potential of<br />
inhaled particles.<br />
This work is concerned with the particulate matter reactivity<br />
investigation by concentration of surface active centres.<br />
Experimental<br />
Both total suspended particles (TSP) and PM 10 measurement<br />
includes integral sampling onto a collection material<br />
(membrane filter Synpor 0.8 µm pore size, 35 mm in diameter)<br />
by sampling equipment VPS 2000 (Envitech, Trenčín) at<br />
flow rate of 960 dm 3 h –1 during sampling period of approximately<br />
24 hours.<br />
The surface reactive spots concentrations of suspended<br />
particulate matter were detected on the spectrometer ERS<br />
220 (GAS, Berlin) with a resonator RSX 216 at room temperature<br />
under following conditions: the microwave power<br />
10 mW, modulation amplitude 0.02 mT, time constant 0.5 s.<br />
The relative intensity of the signals measured for investigated<br />
dust samples was determined by comparing them with those<br />
of Mn(II)/ZnS a Cr(III)/MgO as standard samples. The EPR<br />
spectrum was recorded as the first derivation of the absorption<br />
spectrum at the speed record 14.3 mT min –1 .<br />
The quantitative and qualitative interpretation of obtained<br />
spectra was performed by computer software Origin.<br />
Results<br />
Typical EPR spectra of investigated total suspended particulate<br />
mater and PM 10 samples are illustrated in Figs. 1.–3.<br />
s474<br />
Fig. 1. EPR spectra of total suspended particulates<br />
Fig. <strong>2.</strong> EPR spectrum of PM 10<br />
Fig. 3. Detail of PM 10 EPR spectrum<br />
Wide singlet peak centered at g factor value was identified<br />
in EPR spectra of particulates. The g factors range from<br />
<strong>2.</strong>010 to <strong>2.</strong>093 for measured particle samples as the Table I<br />
shows.<br />
Singlet peak superponed by triplet peak with factor<br />
values g 1 = <strong>2.</strong>1162, g 2 = <strong>2.</strong>0700, g 3 = <strong>2.</strong>0191 was identified<br />
in EPR spectrum of total particulate matter in Fig. 1. It<br />
could be an isotropic triplet (g = <strong>2.</strong>07) with splitting constant<br />
a = 7.6375 +/ 0.5495 mT.