The number of Minnesotans exposed to secondhand smoke fell to an all-time low in 2010, and 9 in 10 people now forbid smoking in their homes, according a new state survey released Thursday.

The survey, conducted every three years by the Minnesota Department of Health, suggests that the state's controversial 2007 indoor smoking ban has produced a dramatic shift in Minnesotans' thinking on the hazards of cigarette smoke.

How dramatic? A majority of smokers now refuse to smoke in their own homes, the survey found.

"This is the first [survey] that captures the effects of the Freedom to Breathe Act," said Raymond Boyle, research director at ClearWay Minnesota, a nonprofit smoking-cessation and research group that partners on the survey. "It's very encouraging."

Nonetheless, about 45 percent of respondents reported being exposed to second-hand smoke at some point in the previous week, down from 57 percent three years ago.

More than 90 percent said they believe secondhand smoke is harmful.

In a spirited debate before the passage of the 2007 law, many bar and restaurant owners argued that a smoking ban would hurt their business. But researchers said Thursday that a recent University of Minnesota study indicates the smoking ban hasn't caused economic harm.

The study, which was separate from the state smoking survey, examined employment changes in bars and restaurants in the state between 2004 and 2008, the latest data available at the time, and found no sign that the smoking ban crimped hiring.

Gradual decline

Overall, the statewide survey found that adult smoking in Minnesota continued a gradual decade-long decline in 2010, dropping from 22 percent in 1999 to 16.1 percent last year and leaving Minnesota well below the national average, 20 percent of adults.

The survey also found:

• Young men with low incomes and little education are the most likely to smoke. In 2010, 21.8 percent of college-aged adults were smokers.

• The number of "heavy smokers" (more than 25 cigarettes a day) has declined from 10.3 percent of smokers in 2007 to 6.3 percent in 2010.

• The use of smokeless tobacco products has increased, from 3.1 percent in 2007 to 4.3 percent in 2010.

Kelly Michaels grew up in a smoky home and tried her first cigarette as a teenager with her sister. The habit lasted more than a decade, until she became engaged. Her fiancé had a son who was roughly the same age she was when she started smoking.

"It dawned on me that this is my family," said Michaels, who now has a 6-year-old daughter. "I never took another drag off a cigarette again."

Michaels hated the smell of smoke in her home, yet smoked there anyway until she quit. Her relatives knew right away to take their own cigarettes outside.

"I think everybody knows how hard it really is,'' said the 41-year-old from Bloomington. "Once you try to quit, you're supportive of others."

Taryn Wobbema is a University of Minnesota journalism student on assignment for the Star Tribune. Jeremy Olson • 612-673-7744