You don't just have to worry about smoke in a wildfire...
On June 17, a fire broke out at a massive, refrigerated warehouse in the Boyle Heights neighborhood of Los Angeles. Flames smoldered inside the roughly 500,000-square-foot building... and clouds of black smoke blocked out the sky.
When a ruptured ammonia line filled the air with poisonous fumes, officials worried about something that could be just as deadly as the flames... polluted air.
They ordered nearby residents to shelter in place. Folks closed their doors and windows and kept their air conditioners running to stay safe from the poisonous gas.
That shelter-in-place order was later lifted, but concerns about air quality remained. A particle-pollution advisory remained in effect through midday today – six days after the fire started.
And this wasn't Southern California's only recent bout with dangerous smoke...
Wildfires triggered another smoke advisory just last month. And a fast-moving wildfire near Spokane, Washington destroyed homes and forced nearly 12,000 residents to evacuate last week.
Emergencies like these make it impossible to ignore air-quality concerns... And while there's no mistaking the danger in thick clouds of smoke, what about when you can't see it?
Harmful air can be invisible and odorless... It's something we encounter in our everyday lives. Worse, it can penetrate deep into your lungs...
The American Lung Association's latest annual State of the Air report found that 152.3 million Americans – about 44% of the population – live in places that earned a failing grade for ozone or particle pollution.
What's more, new research suggests polluted air doesn't just trigger a temporary bout of hacking and wheezing... Over time, it could lead to asthma and chronic obstructive pulmonary disease ("COPD") and worsen existing lung diseases.
Two of the biggest threats in polluted air are fine particulate matter and ground-level ozone.
Fine particulate matter, or PM2.5, is a mix of soot, smoke, dust, metals, and liquid droplets measuring no more than 2.5 microns across. (A micron is one-millionth of a meter.) They're microscopic... which makes them dangerous. While larger particles get caught in your nose and throat, PM2.5 can travel deep into the lungs, reaching the tiny air sacs where oxygen enters your bloodstream.
Ground-level ozone is different. It's a gas created when sunlight and heat react with pollutants from sources like cars, power plants, gas pumps, and factories. That's why ozone levels often climb on hot, sunny days.
The ozone layer high above Earth protects us from the sun's ultraviolet rays. But ozone near the ground will attack the lungs when you breathe it in. It irritates and tightens the airways, making it harder to breathe. The American Lung Association even compares the inflammation with a sunburn inside of your lungs.
Both types of pollutants can set off oxidative stress. That's when unstable molecules called free radicals start to overwhelm the body's defenses, resulting in damage that activates the immune system and causes inflammation.
Short-term exposure may lead to coughing, wheezing, chest tightness, or an asthma attack. Repeat those exposures, and you end up trapping your lungs in a cycle of injury and repair. Over time, that damages cells and tissues. It also reduces lung function.
In fact, research published in January found in a review of 77 studies that exposure to particulate matter unleashes widespread, harmful molecular changes. These include increasing levels of oxidative-stress markers, depleting protective antioxidants, altering how genes control inflammation, and changing the bacterial makeup in your nose and even in the gut to promote oxidative stress.
And that's not all...
Another study published in January followed roughly 3.2 million Danish adults for 18 years. Researchers analyzed individuals' exposure to PM2.5, nitrogen dioxide, and black carbon (or soot). Higher exposure to all three pollutants was linked to a higher chance of developing adult-onset asthma and COPD.
And a study published this month in Environmental Epidemiology tracked 169,713 COPD patients in Northern California. For every 10-microgram-per-cubic-meter increase in average yearly PM2.5 exposure, the risk of death rose 15%. Respiratory-related death rates rose 22%, and COPD flare-ups increased 35%. (For reference, 10 micrograms per cubic meter is slightly more than the Environmental Protection Agency's annual PM2.5 limit of 9 micrograms per cubic meter.)
And remember: Your lungs aren't always the final destination for these pollutants. Very small particles can easily slip into the bloodstream or possibly even travel from the nose to the brain. So it's not surprising that exposure to these ultrafine pollutants is linked to Alzheimer's disease, dementia, and Parkinson's disease.
Two Steps to Protect Your Lungs Against Bad Air
Here's what I recommend if you want to protect your lungs and the rest of your body...
Check the Air Quality Index ("AQI") forecast before heading out. It estimates the expected air-pollution levels in your area, plus the severity of health effects after exposure, on a scale from 0 to 500. A higher number means poorer air quality and greater health concerns.
When pollution levels are high, it's a good idea to limit your outdoor time, like moving exercise indoors and avoiding exerting yourself outside. (The greater your exertion, the more air you'll suck in.) You can find the AQI through your local news station's weather forecast and most weather apps or websites.
Build a cleaner-air sanctuary. During poor-AQI days, close all windows and doors and run an air purifier appropriately sized for the room. I recommend a machine with a "true HEPA" filter that can capture 99.97% of airborne particles – those that are small enough to get deep into your lungs and cause health problems.
I also recommend getting an air purifier with the "AHAM Verifide" logo on the box or in the product description. This means the unit has been tested by the Association of Home Appliance Manufacturers' ("AHAM") independent laboratories.
AHAM measures how efficiently the device cleans the air via the clean air delivery rate ("CADR"). There are multiple CADR scores for pollutants like pollen, dust, and tobacco smoke. A higher CADR score means faster cleaning of the air. Make sure your air purifier's CADR score is at least two-thirds of the total square footage of the room you need clean air in.
What We're Reading...
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Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Health & Wealth Bulletin Research Team
June 23, 2026