Tracking the Sacramento pollutant plume over the western Sierra Nevada. Final report

Technical Report · Sun Mar 01 04:00:00 EST 1998

OSTI ID:678947

Carroll, J J; Dixon, A J

The pollution plume from Sacramento is often directed over the Sierra Nevada foothills east-northeast of the city where the highest local concentrations of ozone are typically experienced. This study used an aircraft instrumented to measure meteorological conditions, ozone and other pollutants to examine the 3-dimensional nature of this plume. The aircraft was flown along three vertical planes oriented perpendicular to the upslope flow at 40, 80, and 120 km downwind of the city, three times each day. A fourth flight measured the same information at 40 and 80 km downwind. These measurements, as well as those documenting the meteorological setting and evolution of surface conditions, are presented. High residual ozone above the surface layer in the early morning hours appears to be necessary to produce afternoon concentrations in excess of 125 ppbv. The moderately polluted days were characterized by low residual pollutant concentrations aloft in the early morning and moderate to weak vertical stratification during the day. The cleaner days had good ventilation with deep layers of near stratification and moderate to strong winds. The maximum ozone concentrations were frequently observed in the afternoon, 40 to 80 km downwind of the city.

• Research Organization: California Univ., Dept. of Land, Air and Water Resources, Davis, CA (United States); California State Air Resources Board, Research Div., Sacramento, CA (United States)
• Sponsoring Organization: California State Air Resources Board, Sacramento, CA (United States)
• OSTI ID: 678947
• Report Number(s): PB--99-159444/XAB; CNN: Contract CARB-94-334
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
AIR POLLUTION MONITORING
AIRCRAFT
CALIFORNIA
ENVIRONMENTAL TRANSPORT
METEOROLOGY
OZONE
PLUMES