State of California
AIR RESOURCES BOARD
State Office Building
Room 1194
455 Golden Gate Avenue
San Francisco, CA
September 20, 1976
10:00 a.m.
AGENDA
76-17-1 Approval of Minutes of August 10 Board Meeting.
76-17-2 Emergency Plan - Consideration of Traffic Reduction
Strategies During Oxidant Emergency Episodes and
Criteria for Combination Oxidant - Sulfur Dioxide
Emergency Episodes.
76-17-3 Staff Report on San Diego Gas and Electric Company
Encina No. 5 Power Plant.
76-17-4 Other Business -
(a) Executive Session - Personnel and Litigation
(b) Research Proposals
ITEM NO.: 76-17-2
Emergency Plan
(a) Consideration of Traffic Reduction Strategies During
Oxidant Emergency Episodes, and
(b) Criteria for Combination Oxidant - Sulfur Dioxide
Emergency Episodes.
RECOMMENDATION
This is an informational report requested by the Board. No
specific action is required.
SUMMARY
(a) The University of San Diego statistical study shows that, at
certain inland locations where high oxidant concentrations
occur frequently in the summer months, the concentrations
observed on weekends are statistically significantly lower
than concentrations observed on weekdays, suggesting that a
strategy of creating weekend traffic patterns when oxidant
emergency conditions are forecast would be effective in
reducing or preventing Stage II and III conditions. Such
strategy would not be equally effective at locations near
the coast and might be counter productive during the winter.
(b) The Department of Health has recommended that a 0.1 ppm
cutoff be applied to the SO2 concentrations as well as the
oxidant concentrations in the criteria for combined
SO2-oxidant emergencies. Analysis of 1975 air quality data for
the South Coast Air Basin suggests that the proposed
criteria would result in a few Stage II episodes which would
not have occurred under the oxidant criteria alone. It
would appear that these episodes would result from adding
relatively low concentrations of SO2 to near episode
concentrations of oxidant, rather than vise versa.
The Board asked the staff to ask the oil companies and power
companies in the South Coast Air Basin to outline their
plans to meet the Emergency Plan requirements to reduce SO2
emissions. The staff report summarizes the comments of the
companies that have responded.
ITEM NO.: 76-17-3
San Diego Gas & Electric Company Encina 5 Power Plant.
SUMMARY
San Diego Gas and Electric Company has started construction of a
fifth generating unit at their Encina power plant and plans to
erect a 400-foot stack to disperse the pollutants from all five
generating units so as to avoid violating the state 24-hour SO2
and one-hour NOx air quality standards at the site of the power
plant.
RECOMMENDATION
The staff believes that adequate data is not presently available
to accurately project the total impact on basin wide air quality
from the use of tall stack dispersion methods such as the 400-foot
stack being constructed at Encina 5. The staff therefore
recommends that it conduct further studies to determine the
following:
(1) Whether the studies conducted by Stanford Research Institute
and Bechtel Power Corporation accurately reflect the total
volume and composition of pollutants which would be emitted
from the 400-foot stack at Encina 5, particularly in light
of recent developments in the availability and cost of low
sulfur fuel oil.
(2) Whether the studies conducted by the San Diego Air Pollution
Control District accurately reflect the total basin wide
impact of the emissions from the 400-foot stack at Encina 5
on ambient air quality in the San Diego Air Basin.
(3) Whether the anticipated emissions from the 400-foot stack at
Encina 5 are likely to interfere with the attainment and
maintenance of ambient air quality standards in the San
Diego Air Basin or other basins.
(4) Whether existing standards for measurement of SO2 and NOx
emissions accurately document the impact of such emissions
on basinwide ambient air quality.
(5) Whether regulations are necessary to require the use of best
available control technology to control the volume of
emissions from tall stacks in order to prevent such
emissions from interfering with the attainment and
maintenance of ambient air quality standards.