High California heat triggers risks for those with asthma, allergies. How to cope

As summer temperatures across Northern California remain in the triple digits, people with asthma and allergies face special risks, health experts warned.

“Hot and humid weather and exposure to pollens, mold spores and air pollution can cause asthma symptoms to flare,” the Allergy & Asthma Network said.

For some, summer heat can alleviate allergies and asthma symptoms, the network said.

But in other cases the heat can exacerbate symptoms and trigger asthma attacks.

“For people with asthma, breathing in hot air, whether dry or filled with moisture, can trigger symptoms because it causes the airways to tighten and narrow,” the American Lung Association said.

Heat also can worsen air pollution, trapping ozone and particulate matter, which also can make breathing more difficult for people with asthma.

“Summer months also increase exposure to different triggers such as tree, grass or ragweed pollen, thunderstorms, campfires and air pollution,” the network said.

Stifling heat also can trap pollutants, smoke or other irritants, the American Lung Association said.

Here’s what to know:

How to avoid asthma attacks in high heat

The American Lung Association has some tips for people with asthma and allergies in extreme heat:

• Check before you go. Check the temperature, air quality and pollution forecast before heading out.
• Stay cool and hydrated. “Drinking plenty of water can help thin any mucus accumulating in your lungs or airways as well as cool off your body.” A dehumidifier and air conditioner also can help you keep cool.
• Keep your medication on hand. Make sure your inhalers and other medication is always accessible.
• Create a clean room in your home. A clean room is a place where you make a dedicated effort to minimize exposure to any fine particle pollution, including pollen, dust, pet dander, mold spores, smog and wildfire smoke that seeps into your home. The EPA also has tips on creating a clean room
• Communicate. Check in often with friends and family, and ask for help if you need it.
• Be prepared for power outages. Power outages may occur in high heat or in blackouts to prevent wildfires. If you use a nebulizer, oxygen concentrator or other electronic device to assist your breathing, plan ahead for power outages.

This story was originally published July 15, 2026 at 3:27 PM with the headline "High California heat triggers risks for those with asthma, allergies. How to cope."