Palo Alto residents enduring an extended stretch of hot weather face a second hazard: ozone pollution severe enough to trigger a regional Spare the Air Alert through Tuesday, Oct. 6.
The Bay Area Air Quality Management District (BAAQMD) extended its Spare the Air Alert citing elevated ozone levels across the Santa Clara Valley and South Central Bay, the East Bay Times reported. The alert was first issued Saturday, Oct. 3. Air quality in Palo Alto's zone is forecast to exceed 100 on the U.S. EPA's Air Quality Index, a threshold the district classifies as unhealthy for sensitive groups.
Ozone at those levels can cause chest pain, throat irritation and congestion. It can worsen asthma, emphysema and bronchitis, and inflame lung tissue. Children, older adults and people with heart or respiratory conditions face the highest risk.
The BAAQMD said high inland temperatures, light surface winds and a delayed afternoon sea breeze are trapping smog at lower altitudes. That is pushing ozone into the "unhealthy for sensitive groups" range in the Santa Clara Valley, the East Bay and the Coast and Central Bay zone that includes San Francisco, according to San Francisco Chronicle reporting.
The district advised residents to exercise outdoors only during early morning hours, when ozone levels are lower. It also asks residents to limit driving.
Heat advisory through Wednesday
The ozone alert sits on top of a heat wave that has already pushed Palo Alto well past seasonal norms. The National Weather Service extended a heat advisory for the Santa Clara Valley through 10 p.m. Wednesday, Oct. 7. Daytime highs are forecast in the mid-90s to low 100s, roughly 15 to 25 degrees above average, according to Watchers.news.
The city of Palo Alto's hot weather advisory warns that people without access to cooling, homeless residents, the elderly and children are at highest risk for heat stroke, heat exhaustion and dehydration. The city advises avoiding outdoor and strenuous activities between 10 a.m. and 4 p.m. and never leaving people or pets in a closed, parked car.
Higher-elevation areas near Palo Alto may also see elevated fire weather conditions through Thursday, Oct. 8, according to the city's advisory.
Where to cool off
Palo Alto's five library branches are open as cooling centers during normal business hours:
- Children's Library, 1278 Harriet St.
- College Terrace Library, 2300 Wellesley St.
- Downtown Library, 270 Forest Ave.
- Mitchell Park Library, 3700 Middlefield Rd.
- Rinconada Library, 1213 Newell Rd.
Rinconada Pool's lap pool is open Monday through Friday, noon to 4:15 p.m., Saturday, noon to 5 p.m., and Sunday, 11 a.m. to 5 p.m. The play pool is open daily, 11 a.m. to 5 p.m. Mitchell Park also has a water park feature for kids.
Santa Clara County operates additional cooling centers across the region.
ABC7 meteorologist Drew Tuma said the warm spell could persist for two weeks, with temperatures remaining well above seasonal norms through the first half of October.
