I have to laugh at your head-scratching over the causes of pollution in the Salt Lake Valley ("Scientists tackle problem of particulate pollution," Tribune, Dec. 22).
When I was a kid in Salt Lake in the '50s, automobiles didn't have emission controls and catalytic converters. Many people heated their homes with coal-burning furnaces or wood-burning fireplaces. Nobody thought anything of the Utah Power and Light plant out on the west side of town, with its smokestacks.
And yet inversions were unknown. You don't suppose today's pollution could have anything to do with too many people, do you?