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PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 696 August 12, 2004 by Phillip F. Schewe, Ben Stein

THE MASSIVE NORTHEAST BLACKOUT of a year ago not only shut off
electricity for 50 million people in the US and Canada, but
also shut off the pollution coming from fossil-fired turbogenerators
in the Ohio Valley. In effect, the power outage was an inadvertent
experiment for gauging atmospheric repose with the grid gone for the
better part of the day. And the results were impressive. On 15
August 2003, only 24 hours after the blackout, air was cleaner by
this amount: SO2 was down 90%, O3 down 50%, and light-scattering
particles down 70% over "normal" conditions in the same area. The
haze reductions were made by University of Maryland scientists
scooping air samples with a light aircraft. The observed pollutant
reductions exceeded expectations, causing the authors to suggest
that the spectacular overnight improvements in air quality "may
result from underestimation of emission from power plants,
inaccurate representation of power plant effluent in emission models
or unaccounted-for atomospheric chemical reactions." (Marufu et
al., Geophysical Research Letters, vol 31, L13106, 2004.)