MEASUREMENTS OF AIRBORNE DUST CONCENTRATION IN TEHRAN EMPLOYING BETA ABSORPTION

M. A. Naimpour1, H. Rahimi1, A. A. Amini1, B. Machaj2

1 Atomic Energy Organization of Iran Nuclear Research Center, Tehran, Iran,
2 Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Dorodna 16, Poland


Measurements of airborne dust pollution were carried out in the northern part of Tehran. In the gauge used for the measurements, the dust from the air is deposited on a fiber glass air filter. The mass of the deposited dust is determined by attenuation of beta particles. The volume of the air is proportional to the pumping time of the air through the filter as the air flow rate is kept constant.
The results of measurements in the form of a diagram of dust concentration variation within a day indicate, in accordance with expectation, considerable difference from day to day. Average variation of dust concentration within a day for 2 months period has two maxima: one in morning hours (9-10 hrs) and the other at night (23-24 hrs). Daily average dust concentration for two months is contained within the limits: 0.063 mg/m3 to 0.192 mg/m3 and in a few cases it overpasses the permissible 0.150 mg/m3.
Further measurements of dust concentration are planned also in other parts of the city.