The Brief

Fireworks on the Fourth of July bring a uniquely abrasive spirit of festivity to Southern California — along with terrible air pollution. Nearly every year, the region experiences its most hazardous air quality on July 4 and 5, even in areas that don’t put on their own pyrotechnics shows.

So what exactly lingers in the air after all those oohs and ahhs? What are we breathing?

As with most things that explode, fireworks emit a lot of particulate matter — a mixture of tiny particles suspended in the air.

With fireworks, the ingredients of that particulate matter are metals that produce blasts or colors, said Scott Epstein, air quality assessment manager at the South Coast Air Quality Management District.

“ Some of those metals are actually toxic to breathe,” he added.

The AQMD, which monitors and regulates pollution in Southern California, lists the metals that can help create different colors: strontium (pinks, oranges and purples); magnesium (silvers); barium (greens).

Some illegal fireworks also contain lead.

“The range of unknowns of what's in there is something people should think about when they make their choices,” said Will Barrett, senior director for nationwide clean air advocacy with the American Lung Association.

But beyond the possibility that the pollution could be toxic, fireworks release high levels of fine particle pollution in the air. In fact, Epstein said the amount of pollution is “ nearly the highest that we see all year.”

This fine particle pollution, which you may have heard about in terms such as “PM 2.5” or “PM 10,” which indicates the size of the particle, can get deep into the lung and cause health issues.

“ Usually anything 2.5 microns or less is what gets really deep into the lungs,” said Dr. Isabel Pedraza, associate professor of medicine at Cedars-Sinai hospital in L.A.

Ingesting these particles can cause dangerous inflammation in the lungs and blood vessels.

This often causes symptoms you can feel immediately, such as decreased lung capacity, coughing and worsening asthma. But it can also increase the risk of heart attacks, strokes and arrhythmias.

Pedraza runs a clinic that primarily treats patients with asthma and COPD. She said the pollution from fireworks exacerbates symptoms of lung disease.

“ After fireworks is always a bit of a busy time,” she said.

She also explained that children will feel the effects more acutely. They tend to have a higher respiratory rate, so they may be breathing in more pollutants. But also: “ They're smaller, and so it takes less concentration to have an effect,” Pedraza said.

How to protect yourself as much as possible

So what to do?

Lower your exposure, every expert said.

Specifically, Epstein highlighted “ staying inside, keeping your windows and doors closed, running an air purifier or your HVAC fan,” to help keep your indoor space clear of pollution.

The pollution often lingers the night of the Fourth, especially if winds aren’t dispersing the pollution.

“ It just sits around, gets trapped by our mountains, gets trapped in kind of the lowest levels of the atmosphere,” Epstein said.

Backyard fireworks may also increase emissions closer to the ground where you’re breathing.

Depending on the wind, areas farther from original sites of the fireworks can be affected as well.

“This stuff can be carried in the air, sometimes miles away, depending on what the wind speed is,” Pedraza said.

This can be a risk not only to those with preexisting health conditions, but also to elderly people, children or outdoor workers.

If you have to be outside, an N95 mask may offer some, though not complete, protection, experts said.

If not fireworks, what?

There are alternatives. Several Southern California cities are putting on drone shows for reasons that include varying from air pollution and fire safety concerns.

But even experts on pollution and lung health differed on how to weigh health risks against the sense of camaraderie and awe inspired by rockets’ red glare on Independence Day.

“ I'm originally from Boston,” Pedraza said, “and they have one of the best fireworks displays every year that I've ever seen.”

Barrett also acknowledged the unique sense of celebration that fireworks can bring, but highlighted the possibility that drones and lasers could replace that.

“That can give you the really amazing family moments, the holiday moments where fireworks have been used — and do it without the heavy dose of pollution,” he said.

Regardless, fireworks celebrations will be happening across Southern California. At the very least, you can be aware of the air pollution from maps produced by AQMD and others.

Epstein warned, though, that backyard or illegal fireworks may create “localized hotspots” of pollution. A neighborhood surrounding that area may have higher concentrations of pollution that may not be captured by a region-wide map.

Four million acres of California’s wildest backcountry could soon be opened to paving roads and logging.

The Trump administration announced last week that it’s pushing forward with a proposal to scrap a 2001 rule that blocks logging, road building and other construction in parts of national forests. The administration argues repealing the so-called “roadless rule” is key to managing vegetation to better prevent wildfires on public lands.

Environmental advocates and other groups worry rescinding the rule would harm pristine habitat and the wildlife it supports, and open up more public land to industrial activities and human access that can cause more wildfires.

And locals are worried about losing access to some of the last protected natural lands in the region.

“What we're dealing with here in the roadless rule is the protection of the backcountry,” said David Browning, president of the Orange County Mountain Bike Association, “where you can actually go out and be having an experience where you don't hear traffic, where you don't see buildings, where you actually remember what it was like before all of us got here.”

In Southern California, large swaths of the Los Padres, Angeles, San Bernardino and Cleveland national forests would lose protections.

Browning, who spoke with All Things Considered host Julia Paskin on Monday, said he’s particularly concerned about the Santa Ana Mountains, where much of Orange County’s backcountry biking trails exist within a roadless area that could be opened to construction.

“Our mission is to protect and expand trail access, and so our entire agenda is to make sure that in a highly populated county, like Orange, that we have available the outdoors to be able to go and enjoy,” he said.

Browning takes issue with the wildfire argument — he pointed to the 2024 Airport Fire, which was sparked when heavy equipment operated by Orange County employees struck a rock. They were moving large boulders that day to, in part, block vehicles from getting into a dry brush area and potentially starting a fire. Browning said the “roadless rule” prevents such access that could increase the risk of fire. A recent peer-reviewed study supports that, finding that although roads are important for managing a fire once it ignites, they’re also more likely to be a place where a fire starts.

Though addressing wildfires and protecting public lands have become heavily politicized under the Trump administration, Browning thinks most locals probably aren’t as divided.

“ I don't think this is a party issue,” he said. “We want to hold onto the outdoors and protect them as best we can.”

There unfortunately isn’t much respite in sight for heat-weary Southern Californians.

Forecasters say this week’s heat wave is likely to be the hottest so far this summer. Extreme heat warnings will be in effect from the National Weather Service for almost the entire region from Tuesday morning through Friday evening.

Temperatures will peak between Tuesday and Thursday.

Highs in downtown Los Angeles are expected to reach around 100 degrees, and the warmest inland valleys will get up to 112. L.A. County beaches will hit the high 80s.

Forecasters have also issued Red Flag Warnings for the interior mountains and foothills of Los Angeles, Ventura and Santa Barbara counties. Gusty winds and low humidity at higher elevations mean fires could spark and spread quickly.

At lower elevations, humidity continues to make the heat feel more sweltering and make it harder to cool down, especially at night. Nighttime temperatures will only get down to the 70s in most places, including along the coast.

A slight cooldown is expected this weekend, though forecasters say temperatures will stay above normal into next week.

The extreme heat this week poses an especially high risk of heat-related illness for people over 65, young children, people who work or spend a lot of time outside and those without access to air conditioning.

Driving the heat

Several factors are behind this week’s heat wave, many of which have also been behind the rest of this summer’s consistently hot weather.

The main driver is a high pressure air system hovering over the southwestern U.S., trapping warm air, compressing it and warming it further, and blocking cooler air from entering the region.

Offshore winds are also pushing warm inland air toward the coast, preventing cooler onshore winds from blowing inland.

“That blocks our natural air conditioning off the ocean from coming in as early as it normally does,” said Weather Service meteorologist Mike Wofford. “So as long as that cool air stays offshore, it heats up on land.”

The offshore winds are not strong enough, however, to significantly dry out the air in the L.A. Basin and cut down on the humidity.

“That's probably going to be around for the whole summer because you’ve got all this warm ocean water that's feeding into that,” Wofford said.

Warmer seawater evaporates faster, adding to moisture in the air and increasing humidity across the region, especially along the coasts.

Air quality warnings

Along with the heat this week, many Southern Californians also have smog to worry about.

The South Coast Air Quality Management District issued an ozone advisory on Monday for inland areas of Los Angeles and Orange counties, much of Riverside County and parts of San Bernardino County. It will remain in effect through Friday evening.

The multi-day smog event is in part driven by the heatwave.

Officials say ozone pollution may reach unhealthy levels or higher in the Santa Clarita Valley, parts of the San Gabriel and San Bernardino valleys, and portions of the San Bernardino Mountains.

Under unhealthy levels, it’s possible for anyone to experience adverse health effects like difficulty breathing and throat irritation. Sensitive populations could experience more serious effects.

Levels are expected to be unhealthy for sensitive groups in the San Fernando Valley, Perris Valley, Mission Viejo, Lake Elsinore, Corona, Hemet, Riverside and Pasadena.

Officials advise certain vulnerable groups — including people with heart or lung disease, those with asthma, pregnant women, children and people over 65 — to limit their time outdoors.

Officials predict that ozone levels will be lower along the coast.