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Influence of aerosol distribution on solar UV flux on the surface
Abstracts
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stages in a form of technological product (powder). At the same time they serve for preliminary purification of the dust-laden gas. The final gas cleaning is made in the third stage. The system peculiarity is a possibility of wide adjustment of inlet and outlet pipe sizes in the cyclones and of the gas passage size in the scrubber. Due to these features a high collection efficiency is achieved without large energy consumption, relative to known similar systems. In comparison with other dust control methods, such as fabric filters and electrostatic precipitators. the system is much less expensive and simple in maintenance. It may be used practically for all kinds of dust in a wide range of gas flow rate. The combined dust collection system has been successfully used in industry of Russia, Kazakhstan, Byelorussia. Technical data obtained for the system during repeated tests are given. The system has been designed in several sizes to clean gases at the rate from 1000 up to 85 000 m3 h-r. The total system efficiency is no less than 99.9% and depends on dust properties and gas flow parameters.
INFLUENCE
OF AEROSOL DISTRIBUTION ON THE SURFACE E. H. Steinberger
Department
of Atmospheric
ON SOLAR
UV FLUX
and A. Dvorkin
Sciences, The Hebrew
University,
Jerusalem
91904
A one-dimensional numerical model has been developed for computing the solar flux in the wavelength region 290-385 nm at ground level. The UV flux depends on I”, namely the flux at the top of the atmosphere, the total ozone content, aerosol amounts and size distribution and the solar zenith angle. The aerosol size-distribution function chosen was the Junge model, however, the parameters of the distribution could be varied, thereby changing the size range of the particles and the total amount of aerosol. It has been found that smaller particles reduce the UV flux reaching the ground more strongly than larger particles, and this for the same amount of total aerosol. In addition, the direct UV flux is more strongly influenced by aerosols than the scattered radiation.
APPORTIONMENT
OF
AEROSOLS, INCLUDING SULFATES, URBAN AREA - AN UPDATE Y. Mamane
Faculty
of Civil Engineering.
IN THE
HAIFA
and E. Loshin
Technion-Israel
Institute
of Technology,
Haifa 32000
This study deals with receptor modeling of fine (< 2.5 pm) and coarse 2.5510 pm) particles in Haifa in order to identify the main sources and their impact on ambient particle concentration. The main results of the second year of this program are presented. The following analysis was performed: (1) Meteorological and statistical analysis of existing ambient air quality data collected by the Haifa District Environmental Towns Association; (2) Measurements of respirable suspended particles (RSP) concentrations and chemical analysis of filter samples, including Pb, SO,, and other ionic species; (3) Collection of fine and coarse particle fraction with a dichotomous sampler and X-ray fluorescence (XRF) analysis of the filters; (4) Scanning electron microscopy (SEM) of samples collected by the dichotomous sampler. In the winter of 1995/1996 the dichotomous sampler was placed in Neve-Shaanan, Haifa, and collected 30 pairs (fine and coarse) samples on Teflon and Nucleopore filters for 24 h each. The filters were analyzed for elemental content (30 elements) by XRF at the Atmospheric Research Exposure Assessment Laboratory (AREAL), U.S. Environmental Protection Agency. Also 500 selected particles were individually analyzed with a scanning electron microscope (SEM). The following results have been obtained from XRF and SEM analyses: Ca was the most abundant element in the coarse fraction (60% abundance versus 22% in the fine fraction). Al and Si were found in lower concentrations in the coarse fraction (22% both). In the fine concentration they contribute 14% (both elements). All values are the ratio of a given element to the sum of the XRF major elements (not including elements with Z 1 11). Sulfur dominates the fine fraction: 53% versus 8% in the coarse fraction. Electron microscopy analyses of the filters were consistent with these results. Chlorides were found at both fractions in small quantities. Contents of V and Ni are highly correlated, indicating the contribution of heavy oil combustion (the Haifa oil fired power plant and the Refineries), Apportionment of ambient particles in Haifa using the Chemical Mass Balance Receptor Model (CMB-7.0) yield inadequate source resolution, Apparently the use of source profiles collected in the U.S.A. may not be suitable for the Haifa Airshed.
1354
stages in a form of technological product (powder). At the same time they serve for preliminary purification of the dust-laden gas. The final gas cleaning is made in the third stage. The system peculiarity is a possibility of wide adjustment of inlet and outlet pipe sizes in the cyclones and of the gas passage size in the scrubber. Due to these features a high collection efficiency is achieved without large energy consumption, relative to known similar systems. In comparison with other dust control methods, such as fabric filters and electrostatic precipitators. the system is much less expensive and simple in maintenance. It may be used practically for all kinds of dust in a wide range of gas flow rate. The combined dust collection system has been successfully used in industry of Russia, Kazakhstan, Byelorussia. Technical data obtained for the system during repeated tests are given. The system has been designed in several sizes to clean gases at the rate from 1000 up to 85 000 m3 h-r. The total system efficiency is no less than 99.9% and depends on dust properties and gas flow parameters.
INFLUENCE
OF AEROSOL DISTRIBUTION ON THE SURFACE E. H. Steinberger
Department
of Atmospheric
ON SOLAR
UV FLUX
and A. Dvorkin
Sciences, The Hebrew
University,
Jerusalem
91904
A one-dimensional numerical model has been developed for computing the solar flux in the wavelength region 290-385 nm at ground level. The UV flux depends on I”, namely the flux at the top of the atmosphere, the total ozone content, aerosol amounts and size distribution and the solar zenith angle. The aerosol size-distribution function chosen was the Junge model, however, the parameters of the distribution could be varied, thereby changing the size range of the particles and the total amount of aerosol. It has been found that smaller particles reduce the UV flux reaching the ground more strongly than larger particles, and this for the same amount of total aerosol. In addition, the direct UV flux is more strongly influenced by aerosols than the scattered radiation.
APPORTIONMENT
OF
AEROSOLS, INCLUDING SULFATES, URBAN AREA - AN UPDATE Y. Mamane
Faculty
of Civil Engineering.
IN THE
HAIFA
and E. Loshin
Technion-Israel
Institute
of Technology,
Haifa 32000
This study deals with receptor modeling of fine (< 2.5 pm) and coarse 2.5510 pm) particles in Haifa in order to identify the main sources and their impact on ambient particle concentration. The main results of the second year of this program are presented. The following analysis was performed: (1) Meteorological and statistical analysis of existing ambient air quality data collected by the Haifa District Environmental Towns Association; (2) Measurements of respirable suspended particles (RSP) concentrations and chemical analysis of filter samples, including Pb, SO,, and other ionic species; (3) Collection of fine and coarse particle fraction with a dichotomous sampler and X-ray fluorescence (XRF) analysis of the filters; (4) Scanning electron microscopy (SEM) of samples collected by the dichotomous sampler. In the winter of 1995/1996 the dichotomous sampler was placed in Neve-Shaanan, Haifa, and collected 30 pairs (fine and coarse) samples on Teflon and Nucleopore filters for 24 h each. The filters were analyzed for elemental content (30 elements) by XRF at the Atmospheric Research Exposure Assessment Laboratory (AREAL), U.S. Environmental Protection Agency. Also 500 selected particles were individually analyzed with a scanning electron microscope (SEM). The following results have been obtained from XRF and SEM analyses: Ca was the most abundant element in the coarse fraction (60% abundance versus 22% in the fine fraction). Al and Si were found in lower concentrations in the coarse fraction (22% both). In the fine concentration they contribute 14% (both elements). All values are the ratio of a given element to the sum of the XRF major elements (not including elements with Z 1 11). Sulfur dominates the fine fraction: 53% versus 8% in the coarse fraction. Electron microscopy analyses of the filters were consistent with these results. Chlorides were found at both fractions in small quantities. Contents of V and Ni are highly correlated, indicating the contribution of heavy oil combustion (the Haifa oil fired power plant and the Refineries), Apportionment of ambient particles in Haifa using the Chemical Mass Balance Receptor Model (CMB-7.0) yield inadequate source resolution, Apparently the use of source profiles collected in the U.S.A. may not be suitable for the Haifa Airshed.