I have been reading how Houston will surpass Los Angeles as the most polluted city this year. Both cities and surrounding areas rely too much on automobiles, and can be dirty, but the climates are quite different. L.A. gets very little rain most years, plus it is surrounded on land by mountains, making for a high pressure zone which traps smog. Houston averages over 45" of rain a year, and low pressure dominates most of the time. Houston gets flushed out far more often than L.A.
Are the measurements biased? What’s up?