I just checked the API doc and do not see Air Quality. I use Air Now to import the info into HE using AirNow.gov Driver
@sesummers, you do not need to have a PWS to get a key from WU. I don't know if this is newer or not since I signed up a couple of months ago, and do not have a PWS. Just sign up for a free account and go to the API Keys tab from your Profile and generate a key.
Within the WU webpage you can search and select a weather station you would like to get current conditions from and, the forecast data is pulled using gps, zipcode locations, etc..
