Bay Area air: Does improving air quality mean it’s OK to go outside?

If you’ve sealed yourself inside your house over the past week because of the Bay Area’s unhealthy, smoke-filled air, you’re in for a respite this week.

An offshore weather system moved in earlier than expected early Tuesday morning, diluting the smoke from wildfires raging throughout California and bringing in cleaner air for much of the Bay Area. The Air Quality Index showed “good” or “moderate”-quality air had settled in different parts of the Bay Area, though with pockets of “unhealthy for sensitive groups” air showing up in San Jose, Gilroy, Pleasanton and Livermore.

Air quality will continue to fluctuate through Friday, but officials are hopeful that a strong weather system “will clean things out” this week and allow the Bay Area Air Quality Management District to lift the Spare the Air alerts that have been in effect since Aug. 18, said spokesman Aaron Richardson.

When air is “moderate,” with a measurement of 51 to 100, it’s generally safe to open windows and go outside, said Dr. Stephanie Christenson, an assistant professor of pulmonology at UC San Francisco.

“It’s safe for people to start getting out to exercise and to start moving around,” said Christenson, who said she finally opened up the windows of her San Francisco home on Tuesday for the first time in a week.

But Dr. Tina Sindher, an immunologist with Stanford Health Care, said she still advises people to be cautious about prolonged exposure to even “moderate” air, given that so much is unknown about the long-term effects of extended exposure to wildfire smoke that Bay Area residents have experienced.

“We’ve had 30 days now of exposure, versus a short-term acute exposure,” Sindher said. “We try to make these guidelines but we don’t completely understand the consequences.”

Richardson also warned that unhealthy air could return over the weekend, with shifting weather patterns bringing in air flow from the northwest and with it, smoke from the huge fires in Northern California and Oregon.

If the air quality degrades again, no one should count on bandanas or surgical masks to protect them from wildfire smoke. Health experts said people should continue to wear them in public to prevent the transmission of COVID-19, but these masks are too loose-fitting to keep out very small smoke particles, which can also pass through cloth. Experts have also cautioned against relying on the more sought-after N95 respirator masks because they are in short supply.

In the meantime, Richardson said “we’re getting some respite.” But if people want to go outside, Richardson said it would be a good idea for them to check out local hourly conditions via the air district website. He also recommends people look for updated readings, sometimes at the neighborhood level, on the Fire and Smoke map from the Environmental Protection Agency.

On AQI charts, “moderate” air measures 51 to 100 and is color coded yellow. Under such conditions, the EPA said it’s safe for most everyone to be outside, except for people who are “unusually sensitive” to pollution. Places with “moderate” readings on Tuesday included downtown San Jose, parts of Oakland, Berkeley’s Aquatic Park, Concord, Livermore and Redwood City.

Christenson voiced caution about people in areas with “orange” readings of 101 to 150, which means the air is “unhealthy for sensitive groups.” According to the EPA, healthy people can be active outside, but it’s risky for older adults, pregnant women and people with heart or lung conditions, such as asthma.

Christenson said older teens are generally OK, but the air in the “orange areas” isn’t healthy for infants and young children. That’s because their lungs and immune systems are still developing and could be harmed by extended exposure to such air. “We worry it could affect them in the future,” Christenson said.

Places in the Bay Area with orange readings Tuesday included the city of Pleasanton and Knox Avenue in San Jose. Gilroy was upgraded to an orange reading mid-Tuesday after getting the red “unhealthy” designation earlier in the day.

Indeed, much of the Bay Area was living with “unhealthy” air or worse over the weekend. “Unhealthy” air, which carries the red color coding, measures 151-200. Sensitive groups should avoid any prolonged or heavy exertion and stay inside, while everyone else should reduce the time they spend outside, the EPA advises. If people decide to go for walks, runs or hikes under such conditions, they should plan to take more breaks.

“Very unhealthy” air, which comes with the purple color coding, also blanketed parts of the Bay Area from Thursday through Monday. “Very unhealthy” air carries readings of 201 to 300, along with warnings that sensitive groups should avoid “all physical activities outdoors” and everyone else should avoid prolonged sessions outside.

Sindher said studies have found links between exposure to wildfire smoke and other forms of air pollution with respiratory diseases, such as asthma and chronic obstructive pulmonary disease. But she also said more recent studies of emergency room visits, including in California, have found a link between wildfire smoke and an increased risk of heart attacks and strokes. She said that’s probably due to the toxins from the smoke getting into the blood stream.

“It’s not just a lung issue,” Sindher said. “People may assume, ‘I’m young and healthy, and I don’t have asthma so I’m OK.’ But I don’t think we’re as safe as we could be.”

Christenson said that some people may think it’s still worth it to go for a walk or run, even when the air is rated “unhealthy.” People have to do their own risk-benefits analysis, she said.

“Exercise can help the immune system and really help mental health,” she said. “You have to monitor how you are feeling and what your body is telling you, if you’re exerting a lot.”

Christenson suggested that people go slowly as they return to exercising outdoors. They could start by walking, and then pull back if they feel any symptoms of smoke exposure, such as shortness of breath, cough, sore throat, fatigue or dizziness.

Source: mercurynews
Bay Area air: Does improving air quality mean it’s OK to go outside?