The massive Northeast blackout

The massive Northeast blackout of a year ago shut off not only electricity for 50 million people in the US and Canada, but also the pollution coming from fossil-fueled turbogenerators in the Ohio Valley. In effect, the power outage was an inadvertent experiment for gauging atmospheric repose with the power grid gone. University of Maryland scientists sampled the air with two light-aircraft flights on 15 August 2003, one outside and one inside the blacked-out region; they also looked at samples from a year earlier. The results were striking: About 24 hours into the blackout, sulfur dioxide was down 90%, ozone was down 50%, and light-scattering particles were down 70% over “normal” conditions in the same area. The observed pollutant reductions exceeded expectations, which led the researchers to suggest that the spectacular overnight improvements in air quality “may result from underestimation of emissions from power plants, inaccurate representation of power plant...