Thousands of residents across parts of California, Nevada, Oregon, and South Dakota have been advised to stay indoors, as levels of fine particle pollution (PM2.5) will have reached “unhealthy” levels as of January 12, 2026, at 6 a.m. ET, the Environmental Protection Agency’s (EPA) AirNow Map shows. 

The EPA is urging people in sensitive groups, including the elderly, children, and those with certain health conditions, to completely avoid prolonged or intense outdoor activities. Everyone else should reduce their participation in long or intense outdoor pursuits. 

This is because physical activity causes people to breathe harder and faster, which means the fine particulate matter can penetrate deeper into the lungs if people are exercising outdoors. 

The EPA warns, “Your chances of being affected by particles increase the more strenuous your activity and the longer you are active outdoors. If your activity involves prolonged or heavy exertion, reduce your activity time—or substitute another that involves less exertion. Go for a walk instead of a jog, for example.”

What Do ‘Unhealthy’ Levels of PM2.5 Mean? 

PM2.5 are tiny, inhalable particles of pollution, 2.5 micrometers or less in size (smaller than a strand of hair), that are considered to be one of the most dangerous forms of air pollution, according to the EPA. 

This is because they get deep into the lungs—and sometimes even the bloodstream—triggering or exacerbating certain health conditions, like asthma, or causing symptoms ranging from coughing and nose, eye, and throat irritation to shortness of breath and chest tightness. 

The Environmental Protection Agency (EPA) uses the Air Quality Index (AQI) to report and classify air quality across the United States. The AQI is a standardized scale ranging from 0 to 301+, which categorizes air quality into the following levels:

• Good: 0 to 50—Air pollution poses little or no risk to the public
  
• Moderate: 51 to 100—Some pollutants may pose a moderate health concern for a very small number of unusually sensitive people
  
• Unhealthy for sensitive groups: 101 to 150—Members of sensitive groups (children, elderly, people with respiratory or heart conditions) may experience health effects; the general public is less likely to be affected
  
• Unhealthy: 151 to 200—Everyone may begin to experience health effects; members of sensitive groups may experience more serious effects
  
• Very Unhealthy: 201 to 300—Everyone may experience more serious health effects
  
• Hazardous: 301+—Health warnings of emergency conditions; the entire population is likely to be affected

What Causes PM2.5?

PM2.5 can come from a variety of sources, ranging from wildfires and smokestacks to emissions from vehicles and power or industrial plants. 

Bishop Gorman and Coronado’s boys basketball teams added another chapter to their rivalry at Saturday night’s Big City Showdown.

And the Gaels made sure they wouldn’t lose a third straight regular-season game to the Cougars.

Gorman, the two-time defending Class 5A state champion, almost saw its 10-point fourth quarter lead evaporate, but the Gaels, No. 4 in the Las Vegas Review-Journal’s Class 5A rankings, pulled through late to hold on for a 62-58 road win at No. 3 Coronado.

“It’s been a great rivalry,” Gorman boys coach Grant Rice said. “Student sections are both great, they always show out. I was proud of our guys, just a fun night. We got a lot of basketball left ahead of us. This league is really tough.”

Gorman’s win capped off the seven-game Big City Showdown. The most surprising result came before Gorman and Coronado took the court, when the Gorman girls crushed Centennial 91-54.

“We practice extremely hard,” Gorman girls coach Sheryl Krmpotich said. “Our master plan, they did to a T. I’m proud of the girls. They executed exactly what we wanted. We played tougher and we played smart.”

The games have started to provide a clearer look at the playoff picture with a month before the postseason. Here are three takeaways from the Big City Showdown:

1. Gorman boys stand tall

Gorman (11-7, 2-0 5A Southern League) was in control most of the way until late in the fourth quarter. Dino Roberts’ layup with just over five minutes left gave the Gaels a 51-41 advantage.

Then Coronado (6-7, 1-1) went on an 8-0 run and later made it a one-score game at 55-53 on a Demari Hunter layup with 2:50 left. Coronado cut the deficit to one possession twice in the final minute, and the Cougars had a chance to win the game, trailing 60-58 with eight seconds left.

But a Jonny Collins 3-pointer missed, Coronado couldn’t control possession and Gorman guard Ty Johnson made two free throws at the other end to seal the win for the Gaels.

“We’re a really balanced team,” Rice said. “We only have two seniors and two juniors that get minutes and the rest are sophomores. We’re learning. … I think the guys needed this big game in Vegas to get their confidence back. We still have to stay grounded because we’re a young team, but we showed we can be pretty good.”

Johnson, who was named the game MVP, led Gorman with 23 points. The sophomore point guard scored 11 points in the fourth quarter to help the Gaels secure the win. Braylen Williams added 13 points for Gorman and Dino Roberts scored 10.

“It just helps us excel,” Johnson said of Gorman’s depth. “We had Hudson Dannels making 3s, (Kameron Cooper) and Braylen hustling on the boards. Defense and rebounding are the two things that’ll get us a (win). We’re going to score, points are going to come.”

Munir Greg led Coronado with 22 points. Missouri State commit Amare Oba scored 16 points and DeVaughn Dorrough added 10 points for the Cougars.

2. Gorman girls dominate

Just like Coronado and Gorman on the boys side, the Centennial and Gorman girls have played close, thrilling games. Not on Saturday, though.

Led by 30 points from Texas commit Aaliah Spaight, the Gaels, No. 1 in the Review-Journal’s 5A rankings, led nearly the entire game in its rout of No. 3 Centennial.

“Every game, we’re getting better. Every quarter we get better,” Krmpotich said. “We still haven’t put four quarters together yet. We want to do that in February.”

Centennial (8-4, 1-1 5A Southern League) had no answers for Spaight and Gorman’s depth. The 5-foot-8-inch guard showcased her scoring range — stepback 3s, jumpers and incredible post moves — passing and defense, when Spaight was matched up with Centennial four-star forward Nation Williams.

“She’s the All-American on our team,” Krmpotich said of Spaight. “She sets a tone at practice. She sets a tone in the game. She is a true leader and you expect that. … She’s an extremely smart basketball player, basketball savvy, so we knew she knew how to guard (Williams).”

Gorman (13-1, 2-0), which is ranked No. 5 nationally by MaxPreps, made 12 3-pointers. Taylor Scandrick added 22 points off the bench for the Gaels. Williams led Centennial with 18 points.

“We can rotate in and out. We have an inside-out game. We have kids that can post, kids that can drive to the bucket, kids than can shoot a 3,” Krmpotich said. We’re very multidimensional, so it’s very hard to defend just one or two people.”

3. Look at 5A

There are still plenty of challengers looking to dethrone Gorman for the 5A boys title race.

One matchup at the Big City Showdown pitted two of those contenders with No. 1 Liberty holding off No. 5 Desert Pines 67-66. Liberty led by 21 points early in the third quarter. Tyus Thomas scored 15 points to pace Liberty (13-5, 2-0).

The Patriots could be the biggest threat to Gorman, and you can’t count out Desert Pines, but there are other contenders in 5A with Democracy Prep and Mojave. Coronado should be primed for a state title run come February.

On the 5A girls side, No. 2 Democracy Prep will get its shots at Gorman and Centennial late in the regular season. Democracy Prep beat Gorman twice last year and came up short to Centennial in the 5A title game.

Contact Alex Wright at awright@reviewjournal.com. Follow @AlexWright1028 on X.