Is Living Close to I-5 Bad For Your Health?

A friend and co-worker is looking to relocate back to Capitol Hill. In his quest for Capitol Hill housing he has talked to a number of friends and agents and had not one, but two people recommend that he not live within a half mile of I-5 because of degraded air quality (a half mile from I-5 on Capitol Hill would put you at 12th.)

Photo from: Seen Not Heard on Flickr.

Having lived two blocks from I-5 in a west facing unit at The Carroll Apartments on Bellevue (rumored to go conversion but hasn't yet) I certainly found that I often had very dirty window sills but didn't notice any change in health when I moved across the street to to the Meritage or half a mile away at Trace Lofts.

Because I'm unwilling to pull out my math degree to figure out some air dispersion modeling I thought I'd ask here if anyone had an anecdotal stories of air quality and I-5, I-90, 520 or 99.

Update: here's a research paper on it, The Exposure of Disadvantaged Populations in Freeway Air-Pollution Sheds: A Case Study of the Seattle and Portland Regions.