*The following is excerpted from an online article posted on HealthDay.
Progress made in limiting kids' exposure to secondhand smoke could be undermined by the increasing popularity of pot, a new study suggests.
"As we are removing cigarette smoke -- and that's a major public policy achievement -- that success will be attenuated by increasing exposure to secondhand marijuana smoke," said lead researcher Renee Goodwin.
The numbers confirm the trend.
Fewer parents are smoking cigarettes who have kids in the home these days -- about 20 percent in 2015 compared with more than 27 percent in 2002.
But marijuana use among cigarette-smoking parents increased dramatically during that same period, indicating that kids in those families could be exposed to more secondhand smoke than ever.
Among parents who smoke cigarettes, pot use increased from 11 percent in 2002 to over 17 percent in 2015, the researchers found.
"The kids who are already exposed to one thing, they're more likely to be exposed to both," said Goodwin, a professor with the City University of New York. "It's even worse for them."
Kids exposed to a combination of secondhand smoke from pot and tobacco are more likely to wind up in the emergency room or suffer an ear infection, according to another study presented earlier this month at the Pediatric Academic Societies annual meeting in Toronto.
In the latest study, Goodwin and her colleagues also found there's been an uptick in marijuana use among parents who don't smoke tobacco, from 2 percent to 4 percent during the same period.
However, marijuana use was nearly four times more common among cigarette smokers versus nonsmokers, the findings showed.
The trend toward marijuana legalization prompted the research team to look at whether parents are smoking pot more often around their kids.
Goodwin explained that she has a friend who works with a government agency in Colorado who often encounters casual marijuana use in other people's homes.
"He knocks on people's doors, someone comes to the door, a puff of cannabis smoke comes out and there's nothing wrong with that. It's not illegal," Goodwin said. "That's fine. But it is secondhand smoke."
To investigate, the researchers evaluated data from the federal National Survey on Drug Use and Health, an annual and nationally representative survey.
Dr. Karen Wilson, division chief for general pediatrics at the Icahn School of Medicine at Mount Sinai, in New York City, noted that a recent study in Colorado found about 16 percent of kids hospitalized for a lung infection called bronchiolitis had blood markers showing they'd been exposed to marijuana smoke.
Worse, about 46 percent of the kids had been exposed to both tobacco and pot smoke, Wilson said.
The study was published online May 14 in the journal Pediatrics.