Bay Area smoke season peaks in September and October, often on the warmest, clearest-looking days. Pets breathe faster than we do and cannot choose to stay inside. Flat-faced dogs, cats with asthma, seniors and any pet with heart or airway disease feel it first, and often before the air looks bad.
Why fall is the risky window here
Northern California’s fire season runs through the dry months and peaks late. By September the hills have had no meaningful rain for months, the wind patterns shift, and smoke from fires hundreds of miles away settles into the Bay.
The part that catches people out is that smoke days often do not feel like bad weather. The air is warm, the sky can look hazy rather than alarming, and a walk feels perfectly pleasant to a person. Fine particulate does not announce itself.
Palo Alto sits where valley air can hold pollutants for days once they arrive, so a smoke event here is often a matter of days rather than an afternoon.
Why pets are affected more than we are
Three reasons, and they compound.
They breathe faster. A resting dog takes roughly twice as many breaths per minute as a person, and a cat more still. More breaths means more particulate.
They are closer to the ground, where heavier particles settle.
They cannot opt out. A dog still needs to go outside, and it will happily run in air a person would avoid, because dogs do not connect exercise with how the air feels.
Fine particulate is small enough to travel deep into the lungs and cross into the bloodstream, which is why smoke affects the heart as well as the airways.
Which pets feel it first
- Flat-faced dogs and cats. Bulldogs, French bulldogs, pugs, boxers, Persians. Their airways are already compromised, and smoke removes the margin. Our guide to brachycephalic airway syndrome explains why that margin was narrow to begin with
- Cats with asthma, for whom a smoke event is a classic trigger
- Any pet with heart disease, since particulate stresses the cardiovascular system
- Seniors, who have less reserve
- Puppies and kittens, whose lungs are still developing
- Birds, which are extraordinarily sensitive to airborne particulate and should be moved to the cleanest room in the house
Signs to watch for
Mild irritation is common and usually settles indoors. What matters is recognizing when it is more than that.
Watch at home:
- Coughing or gagging
- Watery or red eyes, or squinting
- Nasal discharge or sneezing
- Reduced appetite
- Less energy than usual, or reluctance to walk
Call us the same day:
- Coughing that persists indoors or worsens
- Faster breathing at rest, or breathing that looks like effort
- Wheezing, or any noise on breathing
- Open-mouth breathing in a cat, which is always urgent regardless of cause
- Weakness, stumbling or disorientation
- Blue, gray or very pale gums, which is an emergency
- Any worsening in a pet with known heart or airway disease
Count your pet’s breaths in a minute while it is sleeping and write the number down on a clear day. Having a normal to compare against is genuinely useful, and it is the single most helpful thing you can tell us on the phone during a smoke event.
What to do when the air is bad
- Check the AQI, not the sky. Use it the way you would a forecast, and check it before every outing rather than once in the morning
- Keep pets indoors with windows and doors closed when the AQI is unhealthy
- Short bathroom breaks only. Out and back, no walks, no fetch, no dog park
- Cut exercise hard. Exertion means deeper, faster breathing, which is exactly what you are trying to avoid. A dog that gets no run for three days is fine; a dog that runs in heavy smoke may not be
- Run a HEPA air cleaner in the room your pet actually spends time in
- Change HVAC filters and run the system on recirculate
- Wipe the coat and paws after outdoor trips to remove settled ash
- Keep water available everywhere and encourage drinking
- Tire them out indoors. Food puzzles, scent games and short training sessions. Mental work substitutes for physical work better than most owners expect
- Do not put a mask on a pet. They do not seal, pets will not tolerate them, and they can restrict breathing further
Plan before it happens
Smoke events arrive with little warning and often coincide with power shutoffs, which take out your air cleaner and your air conditioning at the same time.
- Identify the room you would close off and keep cleanest
- Have a HEPA cleaner and spare filters before the season, not during it
- Keep two weeks of your pet’s food and anything it is regularly given on hand
- Have a carrier per cat, accessible rather than in the garage
- Keep a current photo and confirm your microchip registration details, since evacuations separate pets from owners
- Know which emergency hospital you would use and have the number written down, not only in your phone
If your pet has existing heart or airway disease, talk to us before the season rather than during a smoke event. Our medical services team can put a plan in place, and our pet diagnostics give us a baseline on the chest and heart, which makes it far easier to tell a smoke flare from a deterioration when the air is bad.
Frequently asked questions
What AQI is too high to walk my dog?
There is no single number that fits every pet. As a practical guide, a healthy adult dog can usually manage brief outings in moderate air, but once the AQI is in the unhealthy range, keep outings to bathroom breaks. For flat-faced dogs, asthmatic cats, seniors and pets with heart disease, restrict much earlier. Judge by the animal as well as the number.
My cat is indoor only. Is she safe?
Safer, but not unaffected. Indoor air tracks outdoor air unless you are actively filtering, and older buildings leak. Asthmatic cats flare during smoke events even without going outside. Run a HEPA cleaner in the room she uses most.
How long do signs last after the smoke clears?
Mild irritation usually settles within a day or two of clean air. Coughing that persists more than a few days after the air improves is not just residual irritation and should be examined, particularly in cats and in any pet with existing disease.
Can I give my pet anything to help?
Please do not give anything without asking us first. Products intended for people are frequently unsuitable and some are dangerous to pets. If your pet has an existing airway condition, call us and we will advise on your specific animal rather than on a general rule.
Is it worse for dogs or cats?
Both are affected. Cats show it less obviously, which makes them easier to miss, and open-mouth breathing in a cat is always an emergency. Birds are the most sensitive of all and should be prioritized.
What if we have to evacuate?
Have carriers, food, a current photo and your microchip details ready before the season. Never leave pets behind, and identify pet-friendly options in advance, because sorting that out during an evacuation is when animals get separated from their families.
Speak to the team at Universal Pet Hospital
If your pet has a heart or airway condition, call us before smoke season on (650) 362-7969 so we have a plan in place.
Published by the team at Universal Pet Hospital.
This article is for general educational purposes only and is not a substitute for an in-person veterinary examination or advice about your individual pet. If you have an urgent concern about your pet, contact Universal Pet Hospital or your nearest emergency veterinary hospital right away.
Universal Pet Hospital
3337 El Camino Real, Palo Alto, CA 94306
Phone: (650) 362-7969
Hours: Monday to Friday 8:00 AM to 7:00 PM; Saturday and Sunday 9:00 AM to 5:30 PM