An environmental organization says smog got worse this year in cities and counties from Maine to Louisiana, and that while the hot, muggy summer is partly to blame, ozone-producing pollutants are the root cause.

"Obviously, the weather is part of the problem," Dan Weiss, Washington representative of the Sierra Club, said Monday in an interview. "But it's not the source. Blaming the weather for high levels of pollution is like blaming the ground for a plane crash. ..."The smoggy summer of '88 is an unpleasant preview of a dirty, unhealthy future unless Congress strengthens the Clean Air Act by restricting emissions from motor vehicles and industrial polluters," he said.

A Sierra Club survey found that through Aug. 3, 41 of 47 cities and counties had peak ozone readings at least 25 percent greater than the safe federal health standard, compared with 36 in this category for all of 1987.

The federal health standard for ozone is 0.12 parts per million. Ozone, which causes respiratory problems, is formed when nitrogen oxides and hydrocarbons combine in the presence of sunlight.

The Sierra Club said the worst reading was 0.24 ppm in Providence, R.I.