Skip to content
Health
Link copied to clipboard

Are there risks from secondhand marijuana smoke? Early science says yes

Research demonstrates that just one minute of exposure to secondhand smoke makes it harder for the rats' arteries to expand and allow a healthy flow of blood.

Jen Zavala at a "Pop-Up Weed Garden" near the Art Museum Thursday, October 20, 2016.
Jen Zavala at a "Pop-Up Weed Garden" near the Art Museum Thursday, October 20, 2016.Read moreSTEVEN M. FALK / Staff Photographer
    by Marissa Ortega-Welch, KALW, External
    Published 

The inspiration arrived in a haze at a Paul McCartney concert a few years ago in San Francisco.

"People in front of me started lighting up and then other people started lighting up," said Matthew Springer, a biologist and professor in the division of cardiology at the University of California-San Francisco. "And for a few naive split seconds I was thinking to myself, 'Hey, they can't smoke in AT&T Park! I'm sure that's not allowed.' And then I realized that it was all marijuana."

Recreational pot was not legal yet in the state, but that stopped no one. "Paul McCartney actually stopped between numbers and sniffed the air and said, 'There's something in the air — must be San Francisco!'" Springer recalled.

As the visible cloud of pot smoke took shape, so did Springer's idea to study the effects of secondhand marijuana smoke.

He started thinking: San Franciscans would never tolerate those levels of cigarette smoke in a public place anymore. So why were they OK with pot smoke? Did people just assume that cannabis smoke isn't harmful the way tobacco smoke is?

Springer was already researching the health effects of secondhand tobacco smoke on rats at his lab at UCSF. He decided to run the same tests using joints.

“By the time I left the concert, I was resolved to at least try to make this happen,” he said.