Is King’s Air Dirtier?

In this week’s Oregonian story on air pollution in NW Portland, this map of relative air quality was included. It is notable for the dark area in the center of King showing a higher concentration of pollutants. The number one contributor is listed as wood burning followed by the catch-all “area” category which includes: business and home fuel use, commercial cooking,
fuel storage and asphalt application. Is there more we could be doing?