Science

Killer whales are killer whales, right? It might be a lot more complicated than that

Published

9 months ago

April 11, 2024

Killer whales are killer whales, right? It might be a lot more complicated than that

More than 150 years ago, a San Francisco whaler noticed something about killer whales that scientists may be about to formally recognize — at least in name.

Charles Melville Scammon submitted a manuscript to the Smithsonian in 1869 describing two species of killer whales inhabiting West Coast waters.

Now a new paper published in Royal Society Open Science uses genetic, behavioral, morphological and acoustic data to argue that the orcas in the North Pacific known as residents and transients are different enough to be distinct species. They propose using the same scientific names Scammon is believed to have coined in the 19th century.

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Killer whales, found in all oceans, are currently considered one global species. The new proposed species would mark the first split of the ferocious apex predators, which, if approved, could have significant conservation and scientific implications — in addition to furthering a decades-long quest to properly classify the whales.

The two proposed species may look indistinguishable to the untrained eye, but there are subtle differences in their fins and markings — and many more unseen ones. They don’t speak the same “language” or nosh on the same food. And they have no interest in hanging out with one another, despite often dwelling in the same waters. Most significantly, researchers say, their DNA shows clear distinction.

Transients — also called Bigg’s killer whales — hunt seals and other marine mammals in small packs in expansive waters stretching from Southern California to the Arctic Circle. And they’re not very chatty while they sneak up on prey — they need to maintain stealth. They sport pointy, triangle-shaped dorsal fins with a solid white “saddle patch” behind it.

Residents, meanwhile, stick to fish — primarily Chinook salmon. They love to gab and hang out with the family. In fact, most offspring stay with their mothers their entire lives. Because fish don’t hear very well, they’re free to chatter as they chow down. Residents hew closer to coastlines, from Central California to southeast Alaska, where salmon congregate. Their fins tend to curve back toward the tail and intrusions of black sometimes extend into their saddle patches.

A third type of killer whale roams the Pacific, but less is known about it; these offshore whales live farther out and prey on sharks and other large fish. A recent study found evidence of another, previously unknown group in the open ocean.

Taxonomy, the scientific discipline of naming and classifying animals, is how we break down critters into species. It’s an intellectual exercise that has real-world consequences.

“We’re facing a global conservation crisis, losing species that we don’t even know exist,” said Phillip Morin, the new study’s lead author and a marine mammal geneticist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center.

If you think of killer whales as one species — a big pie — then killing some of them off here might not be a cause for concern, Morin said. But if you start parsing out species and subspecies — slices of the pie — then it’s suddenly possible to lose a unique, irreplaceable group.

A portion of the fish-eating resident killer whales — known as Southern Residents — is already listed as endangered in the U.S. and Canada. Salmon depletion from overfishing and habitat destruction has starved them, and only about 75 are left now. But if they’re designated as part of a species, the International Union for Conservation of Nature will assess them (and transients) separately.

Study co-author Thomas Jefferson, a marine mammal biologist, also with NOAA’s Southwest Fisheries Science Center in La Jolla, believes the residents would probably be categorized on the conservation union’s Red List as threatened or endangered, possibly even critically endangered.

About 20 years ago, when Morin first began his foray into the world of marine mammal genetics, he said there was agreement that the taxonomy of cetaceans — which includes whales, dolphins and porpoises — was “really poor.”

Classification of land animals is often done by measuring bones, but water dwellers are hard to collect and store. Researchers don’t have extensive collections of whale skulls in museums from around the world, and it isn’t necessarily ethical to acquire them. They needed other tools — such as better genetics, drone recordings and satellite tagging — which didn’t exist yet.

“The genetics has now finally come to the point where we can do this on a broad scale and get the kind of resolution and information that we didn’t have,” Morin said.

Over two decades, researchers went from analyzing thousands to billions of base pairs of DNA from individual killer whales. The enhanced detail has allowed scientists to “look back through time,” Morin said, and answer questions about which killer whale populations are closely related — or not — and when differences emerged.

Based on their genetic analyses, Morin and his team estimate that transients diverged from other orcas between 200,000 and 300,000 years ago, while residents began to split off about 100,000 years ago.

Only a small tissue sample is needed to analyze killer whale DNA to tell a big genetic story.

“We can actually go out with a crossbow and collect a little teeny bit of tissue from a living whale — just shoot a little dart at it and collect a little bit of skin,” Jefferson said.

Of course, scientists in the 19th century dedicated to describing and categorizing whales didn’t have access to this cutting-edge technology.

Virtually nothing was known about marine mammals of the West Coast of North America in the mid-1800s, when Charles Melville Scammon, the whaler, began meticulously documenting and measuring cetaceans, Jefferson said. (Scammon bears no relation to Herman Melville, author of whale-centric “Moby Dick.”)

When Scammon’s paper from 1869 describing a variety of cetaceans of the West Coast, including orcas, made it to the Smithsonian, he had “every reason to believe that his article would be well received,” according to “Beyond the Lagoon,” a biography of the seaman. He knew things no other zoologist did because of his proximity to the whales and keen eye.

In a paper penned three years later, Scammon paints a vivid picture of killer whales, from their “beautifully smooth and glossy skin” to their “somewhat military aspect,” even including drawings. He recounts a gruesome attack, seen in “Lower California,” by a trio of killer whales on a gray whale and her baby.

The orcas assaulted the pair for at least an hour, eventually killing the younger whale while exhausting the mother. “As soon as their prize had settled to the bottom, the trio band descended, bringing up large pieces of flesh in their mouths, which they devoured after coming to the surface,” Scammon wrote. “While gorging themselves in this wise, the old whale made her escape, leaving a track of gory water behind.”

What Scammon didn’t know was that his earlier manuscript would fall into the hands of Edward Drinker Cope, a naturalist who had a reputation for being overly ambitious and warring with colleagues for credit.

Cope, secretary of the Academy of Natural Sciences of Philadelphia, slapped his own introduction on the paper with descriptions and Latin names of the orcas inhabiting the Northern Pacific.

Because of rules governing the scientific naming of animals, Cope would forever be credited with the names believed to have been chosen by Scammon. Nevermind that Cope probably never saw a living killer whale.

The paper also misidentified Scammon and gave him little credit. When the whaler saw it, he was furious, according to the biography.

“It‘s a really, really strange and very weird and dramatic episode in the history of marine mammal biology, how these names came about,” Jefferson said.

Many of Scammon’s observations turned out to be erroneous. Often he logged differences between male and female killer whales rather than differences between species, said Michael Milstein, a spokesperson for NOAA. But his inquiry set the stage for more rigorous research to come.

Morin and his research team propose using the same Latin names from more than a century ago for the species they identified in their recent study.

The researchers call transients Orcinus rectipinnus, noting that, in Latin, “recti means right or upright, and pinna means fin, feather, or wing, most likely referring to the tall erect dorsal fin of males.”

Residents, meanwhile, are labeled Orcinus ater. Ater means black or dark, according to the study, “which probably refers to the largely black color of this species.”

All killer whales are currently classified as Orcinus orca, a macabre nod to their vicious reputation. Some say Orcinus means “of the kingdom of the dead,” a reference to Orcus, a Roman god of the underworld.

There are also common, or informal names, to consider.

The researchers suggest sticking with “Bigg’s” for transients, honoring Michael Bigg, the father of modern-day orca research.

The team plans to consult tribes who have a connection to the resident whales, including the Lummi Nation and Tulalip tribes of the Northwest, before settling on a common name, according to Milstein.

“They decided not to try to rush it to match the paper, but to take the time to make sure it is done in a way that everyone understands and believes in,” Milstein said.

John Durban, an associate professor with Oregon State University’s Marine Mammal Institute and co-author of the new study, said he supports using the name “Blackfish,” which is used by some tribes in the Pacific Northwest.

Complex rules govern the discipline of taxonomy, and typically a specimen must be designated as a reference point when it’s first named.

However, the original specimens studied by Scammon were destroyed or disappeared. According to Jefferson, one at the California Academy of Sciences in San Francisco was wiped out by the historic 1906 earthquake and subsequent fire. Another, believed to have been in Scammon’s personal possession, can’t be found.

So the researchers found stand-ins at the Smithsonian.

Whether the broader community of marine mammal biologists will accept the researchers’ findings — and adopt Scammon’s and Cope’s names — will soon be determined.

The proposal is slated to go before a committee from the Society for Marine Mammalogy, which will vote in a few months on whether to greenlight designation of the species. Jefferson and another author of the new study sit on the committee and will recuse themselves from the vote.

Even today, Scammon has to contend with detractors.

Robert Pitman, a marine ecologist with Oregon State University who was not involved in the study, isn’t “entirely happy” with the names put forth.

The names were conceived “before science, by and large, especially biological science, had any rigor,” Pitman said. “And then the descriptions that [Scammon] puts with those names are just so vague. I’m kind of doubtful that those names will stand.”

Names aside, he expects most marine mammalogists will be on board with the proposed species; many have suspected species-level differences among the well-studied whales of the Pacific Northwest. He said the case for splitting off the mammal-eating transients is particularly strong.

The newly identified species are believed to be harbingers of more to come.

Pitman, who has studied killer whales in Antarctica for over 10 years, said there’s a similar divide between mammal- and fish-eating killer whales in those waters.

There are five identified types, and Pitman thinks at least one will turn out to be a different species. Some look dramatically different.

“And it’ll probably be easier now that somebody’s already made the first step in saying, ‘There’s more than one species out there.’”

Science

2024 Brought the World to a Dangerous Warming Threshold. Now What?

Published

8 hours ago

January 10, 2025

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2024 Brought the World to a Dangerous Warming Threshold. Now What?

Source: Copernicus/ECMWF

Note: Temperature anomalies relative to 1850-1900 averages.

At the stroke of midnight on Dec. 31, Earth finished up its hottest year in recorded history, scientists said on Friday. The previous hottest year was 2023. And the next one will be upon us before long: By continuing to burn huge amounts of coal, oil and gas, humankind has all but guaranteed it.

The planet’s record-high average temperature last year reflected the weekslong, 104-degree-Fahrenheit spring heat waves that shuttered schools in Bangladesh and India. It reflected the effects of the bathtub-warm ocean waters that supercharged hurricanes in the Gulf of Mexico and cyclones in the Philippines. And it reflected the roasting summer and fall conditions that primed Los Angeles this week for the most destructive wildfires in its history.

“We are facing a very new climate and new challenges, challenges that our society is not prepared for,” said Carlo Buontempo, director of the Copernicus Climate Change Service, the European Union monitoring agency.

But even within this progression of warmer years and ever-intensifying risks to homes, communities and the environment, 2024 stood out in another unwelcome way. According to Copernicus, it was the first year in which global temperatures averaged more than 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, above those the planet experienced at the start of the industrial age.

For the past decade, the world has sought to avoid crossing this dangerous threshold. Nations enshrined the goal in the 2015 Paris agreement to fight climate change. “Keep 1.5 alive” was the mantra at United Nations summits.

Yet here we are. Global temperatures will fluctuate somewhat, as they always do, which is why scientists often look at warming averaged over longer periods, not just a single year.

But even by that standard, staying below 1.5 degrees looks increasingly unattainable, according to researchers who have run the numbers. Globally, despite hundreds of billions of dollars invested in clean-energy technologies, carbon dioxide emissions hit a record in 2024 and show no signs of dropping.

One recent study published in the journal Nature concluded that the absolute best humanity can now hope for is around 1.6 degrees of warming. To achieve it, nations would need to start slashing emissions at a pace that would strain political, social and economic feasibility.

But what if we’d started earlier?

By spewing heat-trapping gases into the atmosphere, humankind has lifted global temperatures to record highs.

If nations had started reducing emissions in 2005, they could have made gradual cuts to limit warming to 1.5 degrees.

Starting in 2015, when the Paris agreement was adopted, would have required steeper cuts.

Starting today would require cuts so drastic as to appear essentially impossible.

“It was guaranteed we’d get to this point where the gap between reality and the trajectory we needed for 1.5 degrees was so big it was ridiculous,” said David Victor, a professor of public policy at the University of California, San Diego.

The question now is what, if anything, should replace 1.5 as a lodestar for nations’ climate aspirations.

“These top-level goals are at best a compass,” Dr. Victor said. “They’re a reminder that if we don’t do more, we’re in for significant climate impacts.”

The 1.5-degree threshold was never the difference between safety and ruin, between hope and despair. It was a number negotiated by governments trying to answer a big question: What’s the highest global temperature increase — and the associated level of dangers, whether heat waves or wildfires or melting glaciers — that our societies should strive to avoid?

The result, as codified in the Paris agreement, was that nations would aspire to hold warming to “well below” 2 degrees Celsius while “pursuing efforts” to limit it to 1.5 degrees.

Even at the time, some experts called the latter goal unrealistic, because it required such deep and rapid emissions cuts. Still, the United States, the European Union and other governments adopted it as a guidepost for climate policy.

Christoph Bertram, an associate research professor at the University of Maryland’s Center for Global Sustainability, said the urgency of the 1.5 target spurred companies of all kinds — automakers, cement manufacturers, electric utilities — to start thinking hard about what it would mean to zero out their emissions by midcentury. “I do think that has led to some serious action,” Dr. Bertram said.

But the high aspiration of the 1.5 target also exposed deep fault lines among nations.

China and India never backed the goal, since it required them to curb their use of coal, gas and oil at a pace they said would hamstring their development. Rich countries that were struggling to cut their own emissions began choking off funding in the developing world for fossil-fuel projects that were economically beneficial. Some low-income countries felt it was deeply unfair to ask them to sacrifice for the climate given that it was wealthy nations — and not them — that had produced most of the greenhouse gases now warming the world.

“The 1.5-degree target has created a lot of tension between rich and poor countries,” said Vijaya Ramachandran, director for energy and development at the Breakthrough Institute, an environmental research organization.

Costa Samaras, an environmental-engineering professor at Carnegie Mellon University, compared the warming goals to health officials’ guidelines on, say, cholesterol. “We don’t set health targets on what’s realistic or what’s possible,” Dr. Samaras said. “We say, ‘This is what’s good for you. This is how you’re going to not get sick.’”

“If we were going to say, ‘Well, 1.5 is likely out of the question, let’s put it to 1.75,’ it gives people a false sense of assurance that 1.5 was not that important,” said Dr. Samaras, who helped shape U.S. climate policy from 2021 to 2024 in the White House Office of Science and Technology Policy. “It’s hugely important.”

Scientists convened by the United Nations have concluded that restricting warming to 1.5 degrees instead of 2 would spare tens of millions of people from being exposed to life-threatening heat waves, water shortages and coastal flooding. It might mean the difference between a world that has coral reefs and Arctic sea ice in the summer, and one that doesn’t.

Each tiny increment of additional warming, whether it’s 1.6 degrees versus 1.5, or 1.7 versus 1.6, increases the risks. “Even if the world overshoots 1.5 degrees, and the chances of this happening are increasing every day, we must keep striving” to bring emissions to zero as soon as possible, said Inger Anderson, the executive director of the United Nations Environment Program.

Officially, the sun has not yet set on the 1.5 target. The Paris agreement remains in force, even as President-elect Donald J. Trump vows to withdraw the United States from it for a second time. At U.N. climate negotiations, talk of 1.5 has become more muted compared with years past. But it has hardly gone away.

“With appropriate measures, 1.5 Celsius is still achievable,” Cedric Schuster, the minister of natural resources and environment for the Pacific island nation of Samoa, said at last year’s summit in Azerbaijan. Countries should “rise to the occasion with new, highly ambitious” policies, he said.

To Dr. Victor of U.C. San Diego, it is strange but all too predictable that governments keep speaking this way about what appears to be an unachievable aim. “No major political leader who wants to be taken seriously on climate wants to stick their neck out and say, ‘1.5 degrees isn’t feasible. Let’s talk about more realistic goals,’” he said.

Still, the world will eventually need to have that discussion, Dr. Victor said. And it’s unclear how it will go.

“It could be constructive, where we start asking, ‘How much warming are we really in for? And how do we deal with that?’” he said. “Or it could look very toxic, with a bunch of political finger pointing.”

Methodology

The second chart shows pathways for reducing carbon emissions that would have a 66 percent chance of limiting global warming this century to 1.5 degrees Celsius above the preindustrial average.

Science

U.S. Efforts to Cut Emissions Stalled in 2024 as Power Demand Surged

Published

16 hours ago

January 9, 2025

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U.S. Efforts to Cut Emissions Stalled in 2024 as Power Demand Surged

America’s efforts to cut its climate change pollution stalled in 2024, with greenhouse gas emissions dropping just a fraction, 0.2 percent, compared to the year before, according to estimates published Thursday by the Rhodium Group, a research firm.

Despite continued rapid growth in solar and wind power, emissions levels stayed relatively flat last year because demand for electricity surged nationwide, which led to a spike in the amount of natural gas burned by power plants.

The fact that emissions didn’t decline much means the United States is even further off-track from hitting President Biden’s goal of slashing greenhouse gases 50 percent below 2005 levels by 2030. Scientists say all major economies would have to cut their emissions deeply this decade to keep global warming at relatively low levels.

Since 2005, United States emissions have fallen roughly 20 percent, a significant drop at a time when the economy has also expanded. But to meet its climate goals, U.S. emissions would need to decline nearly 10 times as fast each year as they’ve fallen over the past decade. That seems increasingly unlikely, experts say, especially since President-elect Donald J. Trump has promised to dismantle Mr. Biden’s climate policies and promote the production of fossil fuels, the burning of which generates greenhouse gases.

“On the one hand, it is notable that we’ve now seen two years in a row where the U.S. economy grew but emissions went down,” said Ben King, an associate director at the Rhodium Group. “But it’s far from enough to achieve our climate targets.”

The biggest reason that U.S. emissions have fallen in recent years is that electric utilities have been retiring their older, dirtier coal-fired power plants and replacing them with cheaper and less-polluting natural gas, wind and solar power. That trend mostly continued last year, with a few unexpected ups and downs.

The nation’s demand for electricity, which has stayed more or less flat for two decades, suddenly jumped by roughly 3 percent in 2024, in large part because scorching heat during the summer caused many Americans to crank up their air-conditioners. A smaller factor was that tech companies have been building more energy-hungry data centers in states like Virginia and Texas.

While power companies installed large numbers of wind turbines, solar panels and batteries last year to meet rising demand, natural gas use also rose to record highs, while coal use declined only slightly. The net result was that emissions from the power sector increased an estimated 0.2 percent, according to the Rhodium Group.

At the same time, transportation, the nation’s largest source of greenhouse gases, saw an 0.8 percent rise in emissions last year. Gasoline and jet fuel consumption both increased as Americans continued to drive and fly more after the pandemic. Nearly 10 percent of new car sales in 2024 were less-polluting electric vehicles, but those models still make up a small fraction of total cars on the road and have yet to put a major dent in transportation emissions.

On the flip side, emissions from America’s industrial sector — which includes steel, cement and chemicals — fell by 1.8 percent in 2024. Some of that may have been the result of lost output, as two hurricanes and a strike at the nation’s ports disrupted some factory activity in the fall, Mr. King said.

“It’s a reminder that there’s always some bumpiness in emissions,” Mr. King said. “It’s not just a question of how many electric vehicles are on the road or how much solar we’ve installed. A big portion of our economy still relies on fossil fuels.”

One of the most striking findings in this year’s data was that emissions from oil and gas operations dropped roughly 3.7 percent in 2024. Even though the United States produced record amounts of oil and near-record amounts of natural gas last year, many companies appear to have curbed leaks of methane, which is the main ingredient in natural gas and which can seep into the atmosphere and contribute significantly to global warming.

Over the past few years, the Biden administration and several states have adopted new regulations that require oil and gas producers to detect and fix methane leaks. Many companies also have financial incentives to capture methane to sell rather than vent it into the air.

Between 2014 and 2024, U.S. companies appear to have reduced the amount of methane that escaped, per each cubic feet of gas they produced, by 40 percent, according to the Rhodium Group.

Several experts have estimated that greenhouse gases generated in the United States could start dropping sharply in the years ahead if many clean energy policies stay in place, particularly the 2022 Inflation Reduction Act that pumped hundreds of billions of dollars into low-carbon energy technologies such as electric vehicles, wind turbines, solar panels, nuclear reactors, green hydrogen and batteries.

While Mr. Trump has pledged to scrap many of Mr. Biden’s subsidies and tax credits for electric vehicles and low-carbon energy, it remains to be seen whether Congress will agree.

That law has not yet had a major impact on the country’s emissions, said Mr. King, since it takes time for new factories to open and power plants to get built. But, he said, data shows that low-carbon energy and transportation now make up fully 5 percent of total U.S. private investment.

“That’s a leading indicator that things are changing quickly,” he said.

Science

How to protect yourself from the smoke caused by L.A. wildfires

Published

1 day ago

January 9, 2025

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How to protect yourself from the smoke caused by L.A. wildfires

You don’t have to live close to a wildfire to be affected by its smoke. With severe winds fanning the fires in and around Pacific Palisades, the Pasadena foothills and Simi Valley, huge swaths of the Southland are contending with dangerous air quality.

Wildfire smoke can irritate your eyes, nose, throat and lungs. The soot may contain all kinds of dangerous pollutants, including some that may cause cancer. The tiniest particles in smoke can travel deep into your lungs or even enter your bloodstream.

Conditions like these aren’t good for anyone, but they’re particularly bad for people in vulnerable groups, including children, those with asthma or other respiratory conditions, people with heart disease and those who are pregnant.

Here’s what you should know to keep yourself safe.

Stay indoors

Minimize your exposure to unhealthy air by staying inside and keeping your doors and windows shut.

If you have a central heating and air conditioning system, you can keep your indoor air clean by turning it on and keeping it running. Make sure the fresh-air intake is closed so that you’re not drawing in outdoor air.

Keep your pets inside

They shouldn’t breathe the unhealthy air either.

Check your air filters

Clean filters work better than dirty ones, and high-efficiency filters work better than regular ones. The California Air Resources Board and the South Coast Air Quality Management District recommend filters with a MERV rating of 13 or higher.

You might consider using portable high-efficiency air cleaner in a room where you spend the most time. The U.S. Environmental Protection Agency has information about them here, and CARB has a list of certified cleaning devices here.

Don’t pollute your indoor air

That means no burning candles or incense. If your power is out and you need to see in the dark, you’re much better off with a flashlight or headlamp.

If you’re cold, bundle up. This is not the time to start a cozy fire in the fireplace. Don’t use a gas stove or wood-fired appliances, since these will make your indoor air quality worse, not better, the AQMD says.

The CDC also advises against vacuuming, since it can stir up dust and release fine particles into the air.

Take care when cleaning up

You don’t want your skin to come into contact with wildfire ash. That means you should wear long sleeves, pants, gloves, socks and shoes. The AQMD even wants you to wear goggles.

If you’re sweeping up ash outdoors, get a hose and mist it with water first. That will keep it from flying up in the air as you move it around. Once the ash is wet, sweep it up gently with a broom or mop. Bag it up in a plastic bag and throw it away.

It’s a good idea to wash your vehicles and outdoor toys if they’re covered in ash. Try not to send ashy water into storm drains. Direct the dirty water into ground areas instead, the AQMD advises.

Those with lung or heart problems should avoid clean-up activities.

Discard spoiled food…

If you lost power for a significant length of time, the food in your refrigerator or freezer may be spoiled.

Food kept in a fridge should stay safe for up to four hours if you’ve kept the door closed. If you’ve been without power for longer than that, you’ll need to toss all perishable items, including meat, poultry, fish, eggs, milk and cut fruits and vegetables. Anything with “an unusual smell, color, or texture” should be thrown out as well, according to the U.S. Centers for Disease and Control Prevention.

Refrigerated medicines should be OK unless the power was out for more than a day. Check the label to make sure.

…even if it was in the freezer

Your freezer may be in better shape, especially if it’s well-stocked. Items in a full freezer may be safe for up to 48 hours if it’s been kept shut, and a half-full freezer may be OK for up to 24 hours. (The frozen items help keep each other cold, so the more the better.)

If items have remained below 40 degrees Fahrenheit (4 degrees Celsius) or you can still see ice crystals in them, they may be OK to use or refreeze, according to the federal government’s food safety website.

Ice cream and frozen yogurt should be thrown out if the power goes out for any amount of time. Meat, poultry, seafood, eggs, milk and most other dairy products need to go if they were exposed to temperatures above 40 degrees F for two hours or longer. The same goes for frozen meals, casseroles, soups, stews and cakes, pies and pastries with custard or cheese fillings.

Fruit and fruit juices that have started to thaw can be refrozen unless they’ve started to get moldy, slimy or smell like yeast. Vegetables and vegetable juices should be discarded if they’ve been above 40 degrees F for six hours or more, even if they look and smell fine.

Breakfast items like waffles and bagels can be refrozen, as can breads, rolls, muffins and other baked goods without custard fillings.

Consider alternative shelter

If you’ve done everything you can but your eyes are still watering, you can’t stop coughing, or you just don’t feel well, seek alternative shelter where the air quality is better.

Hold off on vigorous exercise

Doing anything that would cause you to breathe in more deeply is a bad idea right now.

Mask up outdoors

If you need to be outside for an extended time, be sure to wear a high-quality mask. A surgical mask or cloth mask won’t cut it — health authorities agree that you should reach for an N95 or P-100 respirator with a tight seal.

Are young children at greater risk of wildfire smoke?

Very young children are especially vulnerable to the effects of wildfire smoke because their lungs are still rapidly developing. And because they breathe much faster than adults, they are taking in more toxic particulate matter relative to their tiny bodies, which can trigger inflammation, coughing and wheezing.

Any kind of air pollution can be dangerous to young children, but wildfire smoke is about 10 times as toxic for children compared to air pollution from burning fossil fuels, said Dr. Lisa Patel, clinical associate professor of pediatrics at Stanford Children’s Health. Young children with preexisting respiratory problems like asthma are at even greater risk.

Patel advises parents to keep their young children indoors as much as possible, create a safe room in their home with an air purifier, and try to avoid using gas stoves to avoid polluting the indoor air.

Children over the age of 2 should also wear a well-fitting KN95 mask if they will be outdoors for a long period of time. Infants and toddlers younger than that don’t need to mask up because it can be a suffocation risk, Patel said.

What are the risks for pregnant people?

Pregnant people should also take extra precautions around wildfire smoke, which can cross the placenta and affect a developing fetus. Studies have found that exposure to wildfire smoke during pregnancy can increase the risk of premature birth and low birth weight. Researchers have also linked the toxic chemicals in smoke with maternal health complications including hypertension and preeclampsia.

What about other high-risk populations?

Certain chronic diseases including asthma, chronic obstructive pulmonary disease or other respiratory conditions can also make you particularly vulnerable to wildfire smoke. People with heart disease, diabetes and chronic kidney disease should take extra care to breathe clean air, the CDC says. The tiny particles in wildfire smoke can aggravate existing health problems, and may make heart attacks or strokes more likely, CARB warns.

Get ready for the next emergency

Living in Southern California means another wildfire is coming sooner or later. To prepare for the bad air, you can:

Stock up on disposable respirators, like N95 or P-100s.
Have clean filters ready for your A/C system and change them out when things get smoky.
Know how to check the air quality where you live and work. The AQMD has an interactive map that’s updated hourly. Just type in an address and it will zoom in on the location. You can also sign up to get air quality alerts by email or on your smartphone.
Know where your fire extinguisher is and keep it handy.
If you have a heart or lung condition, keep at least five days’ worth of medication on hand.

Times staff writer Karen Garcia contributed to this report.