A new study shows trees in mid-city Los Angeles absorb up to 60% of carbon dioxide emissions during spring and summer when the trees are most active.

In 2021, researchers from the University of Southern California placed 12 sensors in central L.A. to monitor carbon dioxide levels.

Will Berelson, professor of earth sciences, environmental studies and spatial sciences at the University of Southern California-Dornsife, said trees are surprisingly effective at lowering carbon dioxide levels in the air.

"The input of CO2 from cars is predicted to be a certain level," Berelson explained. "But when we look for CO2, we find much less. This difference is due to uptake of CO2 by trees."

Berelson pointed out emissions are like passengers on a train, as wind moves pollution through the city, where some get picked up and dropped off. The sensors measure the pollution in real time. The research published in the journal Environmental Science and Technology found trees absorb about 30% of carbon dioxide, averaged over 24-hour periods over a year. So clean energy, improved public transit and broader emissions reductions are still needed.

Berelson noted the sensors, called a Carbon Census Array, will track carbon dioxide levels for years to come.

"The City of L.A. is always committed to reducing emissions and it isn't clear how they're going to keep track of whether their emissions have actually lowered or not," Berelson observed. "But we've got a way to now track emissions and quantify emissions."

The sensor network is now being expanded, with 12 additional sensors reaching out to Santa Monica on the west side of the city.

If they have not already, North Dakotans are urged to become familiar with an online tool detailing air quality in their area, as environmental officials said smoky air from expanding wildfire seasons requires more awareness.

Forecasters recently warned north-central states including North Dakota would see stretches of smoke-filled air or hazy skies due to wildfires burning in Canada.

Ryan Mills, ambient air monitoring manager for the North Dakota Department of Environmental Quality, said until recently, the state would not see winds pushing smoke here until deeper in June or early July but things have changed.

"The last few years, we've been seeing this kind of tick-up right away in May," Mills observed. "It's kind of like we've had to expand our fire season, if you will."

His office does not track the root causes of longer and more destructive wildfire seasons but researchers said climate change is a factor. When conditions surface, the website and mobile app AirNow.gov provides up-to-date information on local air quality. Residents, especially those with respiratory issues, are urged to limit outdoor activities.

Mills advised when there's an air quality alert and you can start to smell the smoke, it is time to block spaces where the air can seep into your house.

"Closing your windows, things of that nature," Mills recommended. "Obviously, don't be going in and out."

Other tips include adjusting the settings on air conditioners or vehicle vents to recirculate indoor air. Online maps and other tools are often color coded to further illustrate how safe it is to be outside for long periods. When colors such as orange, red and purple come into play, it means the air quality has worsened.


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A bill to legalize cigar smoking in designated Montana barrooms has failed a third reading in the state House. Similar legislation is introduced most years, although polls show it is unpopular among Montanans.

The 2005 Montana Clean Indoor Air Act outlawed smoking in indoor public spaces and workplaces to reduce secondhand smoke and its negative health effects. Before the law passed, Helena happened to be a laboratory for those effects when a city ordinance outlawed public smoking for six months in 2002.

Richard Sargent is a retired family physician in Helena, who also volunteers with the American Heart Association. He said changes to air pollution rapidly affect health.

"We had all kinds of physiology studies showing the things that lead to heart attacks happen fairly rapidly with exposure to secondhand smoke," Sargent pointed out. "Thirty minutes is enough."

Sargent was the lead author of a study which found the rate of heart attacks in Helena decreased about 40%, from 40% to 24%, the year the ordinance went into effect.

Sargent noted the bill started with distinct buildings allowing cigar smoking outside of taverns and then changed to separate rooms in a shared building. He stressed there is no way to isolate airflow in such a setup.

"The American Society of Heating, Refrigeration and Air Conditioning Engineers has stated repeatedly that there's no ventilation system that'll handle secondhand smoke," Sargent added. "It just can't be done."

Among those surveyed, 77% of Montana voters oppose legalizing cigar smoking in bars and 89% support the Clean Indoor Air Act, according to an American Cancer Society poll.


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As Cleveland tightens its air quality standards for the first time since 1977, health officials are urging residents to take simple steps at home to reduce their exposure to harmful pollutants.

The Environmental Protection Agency reported Americans spend about 90% of their time indoors, where air pollution levels can be two to five times higher than outdoor air.

Richard Stewart, public information officer of the Department of Public Health for the City of Cleveland, said the city's push is part of its efforts to engage local residents with new monitoring tools and resources through its "CLEANinCLE" initiative.

"A lot of folks don't realize small changes inside the home can really improve your quality of life," Stewart pointed out. "For example, taking your shoes off before you come in the house, checking for lead paint dust, cracking windows. Just regular cleaning can make a big difference in improved air quality in your house."

CLEANinCLE is a community air monitoring project, including sensors in multiple neighborhoods. The health department hosts two public meetings this week, one Wednesday from 6 p.m. to 7:30 p.m. at the Frederick Douglass Recreation Center and another on Thursday at the Community of Faith Assembly. Both events include free in-home air assessments and raffles for air purifiers and electric stoves.

While many cities face water-related lead risks, Stewart noted one of Cleveland's biggest concerns is still old paint. Officials are asking residents to look out for cracking or peeling paint surfaces, especially in older housing and report issues which could expose children to lead.

"There's no amount of lead that's acceptable in a child's bloodstream," Stewart emphasized. "If you see that 'alligator paint,' where it's cracking and kind of fizzling on the house, contact your landlord. And if you're not getting any results, contact us."

The city also has a Lead Hazard Control Grant Program to help eligible property owners remove lead paint.