In 1958 trash collection programs were established, and backyard incinerators were banned in the hope of reducing smog. However, it was estimated that massive amounts of gasoline were evaporating from storage tanks, fuel pump nozzles, and delivery trucks. This was also considered a serious contributor to smog, and over the next 20 years several new rules, and several new devices, were put in place to alleviate it. There was still a great deal of smog, now identified as photochemical smog, despite the changes. The major remaining problem was ________.
the large distances traveled daily by solitary commuters
too many coal-fired power plants along the coast
insufficient city funding to improve waste dumps
the influx of new manufacturing, with new chemicals
indoor pollution from new houses, with new furniture