oday's flight (RF05) was a brief sampling of pollution with a 7500' MSL 
leg west of Denver, a descent into Centennial airport for a low 
approach, a climb to 22,000 feet, followed by a brief pass through small 
cu forming in the mountains west of Denver.   The boundary layer was 
very low (below about 6500 MSL), which capped high levels of pollutants 
from the Denver metro area, with cleaner air above.   There were a few 
layers above the BL, for example an inversion present at 16,000 feet and 
a wind shift from south (low) to northerly (higher) at 9,000.   The air 
dried out considerably above about 16,000.

Jeff Stith