Julie Woodside enjoys living in the Arden Arcade area northeast of downtown Sacramento, but lately she’s been worried about the occasional whiff of marijuana coming from a nearby home.

“It blows out of his window and all summer long I’m coping with, ‘should I open my window? Do I want to get high today?’ And I don’t want to get high, ever.”

She says she’s not against her neighbors using cannabis, but she does wonder if it’s affecting her health. She got curious about why Californians don’t see the same kind of messaging around pot use that they do for secondhand cigarette smoke. 

So she reached out through CapRadio’s “Great Question!” to ask whether any organizations are drawing attention to the health risks of marijuana smoke.

'Parallel Paths'

The short answer is yes. Though California already forbids smoking in public places, many cities and counties are passing local ordinances to make it clear that marijuana is forbidden anywhere tobacco is. Just last week, the city of San Ramon approved a cannabis ban in all public spaces. California landlords can also prohibit marijuana use on rental properties.

Earlier this fall the California Department of Public Health  launched a searchable directory of smoke-free policies by city. It’s part of the department’s “Secondhand Dangers” campaign emphasizing the risks of inhaling smoke through joints, cigarettes, vapes, or other methods. An online survey they conducted found nearly 40 percent of Californians reported exposure to secondhand marijuana smoke in 2018, up from 21.5 percent in 2016.

Cynthia Hallett with the Berkeley-based advocacy group Americans for Nonsmokers’ Rights has been on a mission to get cities to go entirely smoke-free. Like our question asker Woodside, she’d like to see the health concerns around marijuana smoke become as prominent as warnings about secondhand cigarettes. 

“They’re on these parallel paths and they’re not really in collaboration,” she said of tobacco and marijuana regulation. “That’s created some challenges in terms of what public health departments are able to do with respect to marijuana education.”

That’s partly because California scientists don’t have decades of research on the long-term effects of cannabis smoking, like they do with tobacco. It’s illegal federally, so research funding is hard to come by.

'It’s still smoke'

But there is reason for concern around secondhand pot smoke, said UC San Francisco cardiologist Matthew Springer. His work with rats suggests that a minute of exposure to either secondhand marijuana or tobacco smoke has the same negative effect on blood vessel performance. He says joints and blunts contain many of the same cancer-causing chemicals as cigarettes, and that inhaling those ultra-fine particles can lead to severe damage to the heart and lungs. 

“We really need to get through to people,” Springer said. “There’s a lot of wishful thinking in this assumption that marijuana somehow is just good for you … Not at all. Even if there are legitimate potential uses for cannabis, it’s still smoke. And smoke is going to be bad for you regardless of its source."

Still, another study from a UCLA physician has suggested more evidence is needed to prove a significant risk of lung disease from secondhand marijuana smoke. In a news release about that study, the National Organization for the Reform of Marijuana Laws stated that “cannabis smoke exposure fails to possess the same sort of significant adverse pulmonary effects as does tobacco.”

California recently allocated $3.8 million to the new UC Nicotine and Cannabis Policy Center at UC Merced in hopes of learning more about the short and long-term effects of secondhand marijuana. 

Woodside was also worried about whether nonsmokers can actually get high from nearby marijuana. The answer to that one depends on the situation. 

A study from the National Institutes of Health found that nonsmokers who inhaled marijuana smoke for three hours in a well-ventilated space did test positive for THC, the psychoactive ingredient in marijuana, but at well below the level needed to fail a drug test. In other scenarios where people were in confined, unventilated spaces and exposed to stronger weed, they were more likely to fail a drug test and experience mild impairment. 

And some veterinarians say your dog can get high, too.

Making spaces for cannabis

But in some parts of California, there’s a push to create public spaces for pot consumption. San Francisco now issues permits for cannabis-friendly events. In the spring of 2018, Sacramento approved a temporary marijuana permit for a pot-themed festival. 

This October, West Hollywood opened a restaurant with a designated areas where patrons can peruse a menu of edible and smokable cannabis products. The owner of the restaurant told Eater magazine that he installed a robust filtration system in the building to prevent smoky air from bothering patrons. Also in West Hollywood, a business combining a wellness center and “cannabis boutique” is set to open next year. 

Other cities are already following suit with cannabis lounges and cafes. A bill that would have established a state license for those businesses did not move forward in the last Legislative session. 

Hallett says her group is concerned about nonsmoking employees and patrons being exposed to unhealthy air in cannabis lounges. And she worries that permitted outdoor events could cause marijuana smoke to drift to nearby areas where nonsmokers could inhale it. 

“If you think about being at a concert, or being at a baseball stadium … we don’t allow cigarette smoking,” she said. “But [cannabis smoke] could be hazardous to sensitive people.”

Question asker Julie Woodside said she’s glad to know that there are people working on this issue. She didn’t realize until reading about Springer’s research that marijuana smoke carries carcinogens. 

“I'm surprised the smoke is similar to tobacco when we 'know' that cigarettes have chemicals added beyond what's in the plants,” she said in an email. “That's fascinating.”

Clarification: This story was changed to clarify that Dr. Matthew Springer worked with rats, not mice, to study the cardiovascular effects of secondhand marijuana smoke.