Let’s face it: neither smog nor stacks of garbage are high on anyone’s list of coveted lifestyle amenities.  When you’re deciding whether or not to move to a new city, it can help to know whether that city is particularly clean or polluted.  Here’s some information on the cleanest U.S. cities.

Why it matters
Granted, if a city has a great deal else to offer, cleanliness may be relatively low on your list of things to worry about.  But polluted cities can damage your health, especially if you’re very old or very young.  The National Institutes of Health has funded studies showing that children living in areas with dirtier air are more likely to have more poorly functioning lungs compared to their cleaner-air peers.  Higher levels of ozone, found in urban smog, have been linked to higher levels of childhood asthma.  Sewage and water-contamination issues bring an entirely different set of health risks into play.  Simply put, a cleaner city can mean a higher quality of life.

Where to look for the cleanest cities
So which are the cleanest U.S. cities?  Two surveys released in 2008 — one in Travel & Leisure magazine, the other by Reader’s Digest — put Portland, OR at the top of the list.  A city of about 550,000, Portland gets top marks for its “smart growth” approach to urban planning, in which urban development is surrounded by designated agricultural land.  Downtown is well served by public transit, reducing the number of cars on the road and therefore air pollution.  As for waste management, Portland is currently in the midst of the “Big Pipe Project,”an updating of its sewer system.  The city is so proud of the Big Pipe Project it even recently installed a commemorative sculpture near the Willamette River.

The readers of Travel & Leisure also nominated Minneapolis/St. Paul, MN as one of the cleanest cities.  With a combined population of about 630,000, the cities were cited for access to public parks and the outdoors, environmental awareness, and availability of public transport.  Minneapolis has a well-developed Clean City program to fight litter and graffiti and publishes an annual Greenprint Report that checks the city’s progress on air pollution and sewer quality, among other topics.

Less densely populated Western cities have fewer cars to contribute to smog.  So when the American Lung Association surveyed the cleanest cities in terms of air pollution, cities such as Cheyenne, WY (population 55,000), Santa Fe, NM (population 65,000), and Bismarck, ND (population 59,000) ranked high.

The worst offenders, by contrast, were mostly industrial cities (Pittsburgh, PA and Birmingham, AL) or cities which grew up in an era of planning for cars rather than public transportation (Los Angeles, CA; Dallas/Fort Worth, TX; Charlotte, NC).  Many California cities in particular, such as Bakersfield and Fresno, benefit from being in a state with a credible public-policy commitment to the environment, but have high levels of smog and air pollution, thanks to local industry and smog-spewing traffic.

So if you’re looking for a clean city, rather than a polluted city, look for cities where there are lots of alternatives to driving a car (see: The Best Cities for Bikes).  Also look for cities which have been able to update their sewage systems recently, such as Austin, TX, which completed a $400 million upgrade to their system through the  Austin Clean Water Program in March 2009.

Finally, see if the city puts a high priority on the outdoors: public parks, riverfronts, walking or biking trails.  Even a city with a long history of industrial pollution may be getting greener — and cleaner.