Culture
An Amazingly Precise New Tool to Measure Roadway Pollution
Five percent of vehicles are responsible for 90 percent of toxic emissions. Now we can figure out who the culprits are.
Every few weeks, it seems, there's a new report on the hazards of living near a busy road. Asthma. Heart disease. Infant health risks.
But measuring roadway air pollution and its sources is difficult. Not long after exiting the tailpipe, emissions blend together in a cloud above the street, making it difficult to pinpoint the worst offenders. Five percent of vehicles -- the old, the broken, or the poorly designed -- are responsible for 90 percent of toxic emissions.