State of California

State Building
107 South Broadway
Los Angeles, CA

October 22, 1981
10:00 a.m.



81-22-1 Status Report: Ozone Modeling for the South
Coast Air Basin. (Report will be available
at hearing.) Continued to 11/18/81.

81-22-2 SCM, NOx from Cement Kilns was held over and
heard on 10/22. Materials are in 10/21 Board

81-22-3 Other Business
a. Closed Sessions
1. Personnel (as authorized by State Agency Open
Meeting Act).
2. Litigation (Pursuant to the attorney-client
b. Research Proposals 001
c. Delegations to Executive Officer


ITEM NO.: 81-22-2B.1

Research Proposal No. 1046-86 entitled, "Visibility Reduction as
Related to Aerosol Constituents."


Adopt Resolution 81-62 approving Proposal No. 1046-86 for funding
in an amount not to exceed $170,284.


Visibility reduction caused by air pollution, in addition to
being an aesthetic blight, is linked to acid precipitation and
possible adverse health effects, and it may result in significant
economic losses either direct or indirect. California
experiences both the best and poorest visibility conditions in
the country, and a recent ARB sponsored study has shown that the
poor visibility conditions result largely from poor air quality
rather than being purely a meteorological phenomenon.

Several recent studies have attempted to relate air quality
measurements to light extinction. However, recent research has
shown that measurements of particulate nitrate and sulfate are
prone to errors because of artifact loss and/or formation of
sulfates and nitrates on filter surfaces. The Air and Industrial
Hygiene Laboratory has just completed two successful research
projects for the Air Resources Board that are helping to identify
and to minimize artifact occurrence in sulfate and nitrate
particle analysis.

Only recently have atmospheric researchers begun to understand
the importance of carbonaceous particulate matter in visibility
reduction. Primary carbon particulate emissions will increase
drastically as dieselization of the light duty motor vehicle
fleet occurs. Also, the role of water vapor and its effect on
light scattering by particles has been confounded by possible
sampling artifacts, and as a result, it is not yet well

The objectives of this one-year study are to: 1) determine the
relationship between visibility reduction and aerosol and gas
concentrations under minimum artifact sampling conditions, 2)
determine the total light extinction caused by scattering and
absorption of light in the Bay Area and South Coast Air Basin, 3)
measure the gaseous components which serve as precursors to
visibility reducing particles, and 4) continue field measurements
which will contribute to our ability to reduce sampling errors
still further.

The proposed objectives will be accomplished through laboratory
development of measurement techniques, field measurements at
three urban sites for six days, and sample analysis.
Interlaboratory comparison work as well as replicate analysis
will determine the precision and accuracy of the measurement
techniques employed in this study.

This study will provide valuable information on the relative
roles of sulfate, nitrate and carbonaceous particles in
visibility degradation in the state of California. The proposed
work will also increase our understanding of the occurrence of
artifact sampling problems and the importance of atmospheric
water vapor in visibility reduction.

This information will assist the Board in developing strategies
to protect against visibility degradation in California caused by
excessive atmospheric concentrations of aerosol particles.