The air quality index Wednesday morning reached the “unhealthy” benchmark in cities across the United States including Seattle, Los Angeles and Pittsburgh. Major cities most often see these air quality index spikes after Fourth of July celebrations, said Dan Westervelt, an associate research professor at Columbia University and air pollution adviser to the State Department. “Basically, there was a huge spike particulate matter pollution last night. It’s still lingering around today, but I expect it wont last tomorrow,” Dr. Westervelt said. “I think the risk to healthy individuals is fairly low, since it is so short-lived.”

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Persons: Dan Westervelt, It’s, Westervelt, “, ” Organizations: Columbia University, State Department Locations: United States, Seattle, Los Angeles, Pittsburgh, West Coast