Wildfire Smoke & Cats: AQI Action Levels, Clean-Room Setup, and When to See a Vet

❤ By Pawfect Cat Care Editorial Team • Updated: August 2025

⇒About this guide: Written by the Pawfect Cat Care editorial team and fact-checked with reputable veterinary sources. For educational purposes only—not a substitute for professional veterinary advice.

Quick take: Wildfire smoke can irritate a cat’s eyes and airways—even indoor cats aren’t fully shielded. This guide shows simple steps to cut smoke indoors, what to do at each AQI level, and the warning signs that require a veterinarian. A printable action table is included.

Table of Contents

1. Why Smoke Matters for Indoor Cats
2. AQI Basics: What the Numbers Mean
3. AQI Action Table for Cat Parents
4. Create a Clean-Room (Fast)
5. DIY Air Purifier (Corsi-Rosenthal Box)
6. Hydration, Food & Litter Box Tweaks
7. Red-Flag Symptoms: Call a Vet
8. FAQs
9. Sources

1) Why Smoke Matters for Indoor Cats

Wildfire smoke carries tiny particles (PM2.5) that can travel deep into the airways and irritate the eyes, nose, and throat. Seniors, flat-nosed breeds, and cats with heart or respiratory disease are more vulnerable. Staying indoors helps, but smoke can still seep through windows and vents, so proactive indoor air management is essential.

Related quick-reads on our site: Heat Safety Guide • Wet vs Dry Cat Food • Urinary Health • Cat Anxiety • Why Is My Cat Meowing So Much?

2) AQI Basics: What the Numbers Mean

The Air Quality Index (AQI) translates pollution into categories: Good (0–50), Moderate (51–100), Unhealthy for Sensitive Groups—USG (101–150), Unhealthy (151–200), Very Unhealthy (201–300), and Hazardous (301+). During wildfire events, the main driver is usually PM2.5. For most homes, you should start reducing outdoor time for pets at USG and move to indoor-only routines once AQI is Unhealthy or worse.

3) AQI Action Table for Cat Parents

AQI Level	What to Do for Your Cat	Notes
0–50 (Good)	Normal routines; keep water fresh.	Track local AQI so you can react quickly if it rises.
51–100 (Moderate)	Short outdoor time only if needed; start closing leaky windows; run an air purifier in main room.	Sensitive cats (asthma, seniors) may already need indoor-only.
101–150 (USG)	Indoor-only except quick bathroom breaks; choose a clean-room with purifier on high; gentle play only.	Watch for eye redness, coughing, unusual lethargy.
151–200 (Unhealthy)	Keep all cats strictly indoors; seal windows/doors; run purifier(s) continuously; move nap spots far from windows.	Avoid any outdoor exercise; monitor closely for breathing changes.
201–300 (Very Unhealthy) / 301+ (Hazardous)	Shelter in the clean-room; add a second purifier or a DIY unit; limit door opening; prepare for possible vet care if symptoms appear.	If you’re feeling symptoms from the air, your cat likely is too—treat as urgent.

4) Create a Clean-Room (Fast)

Pick the smallest comfortable room (bedroom or office). Shut windows, close unused vents, and place a HEPA purifier or a DIY unit near the cat’s resting area. Use a towel at the door’s bottom to reduce leaks. Keep fresh water and a litter box inside if AQI is very high. Rotate soft bedding; smoke odors cling to fabric.

Fan placement: Use gentle airflow that circulates through (not at) the cat’s face. Position purifiers away from curtains and corners for better intake.

5) DIY Air Purifier (Corsi-Rosenthal Box)

If you don’t have a HEPA unit, build a DIY purifier in 15–20 minutes using a box fan, four MERV-13 filters (20"×20"), cardboard for a top shroud, and duct tape. Place it in the clean-room and run on medium or high during smoky periods.

1. Arrange four filters in a square (arrows pointing inward), tape edges to seal.
2. Place the fan on top blowing out (pulling air through filters), tape to seal.
3. Add a cardboard shroud on the fan’s front to improve efficiency.
4. Label the date; check filters weekly and replace when dark or after prolonged smoke events.

Safety: Use a modern, UL-listed fan; don’t leave it running unattended on high heat surfaces. Keep away from curious paws.

6) Hydration, Food & Litter Box Tweaks

• Multiple water stations: Two or three wide bowls or a quiet fountain. Drop a single ice cube if your cat likes cooler water.
• Moist meals: Lean on wet food to support hydration; see our wet–dry mixing guide.
• Routine for calm: Short, gentle play in the morning/evening can reduce restlessness; see cat anxiety tips.
• Litter placement: Keep boxes away from drafty doors and smoky windows; scoop more often (smoke odors can stress cats).

7) Red-Flag Symptoms: Call a Vet

Seek veterinary advice the same day if you notice persistent coughing, noisy or open-mouth breathing, fast breathing at rest, unusual lethargy, disorientation, blue-tinged gums/tongue, or eye inflammation with discharge. Cats with asthma or heart disease can worsen quickly—don’t wait if breathing looks labored.

8) FAQs

Should my cat wear a mask outdoors? No. Masks are not designed for cats and can impede breathing. Keep outings brief or skip them entirely during smoky days.

Which filters should I buy? Look for purifiers rated for PM2.5 with a true HEPA filter. For DIY units, use MERV-13 filters sized to match your fan.

Windows cracked for “fresh air”? Keep them closed during smoke events; bring in outside air only when AQI improves.

How do I track AQI? Use your local weather app or a national AQI map; set alerts and plan the day around cleaner hours.

⇛Sources

1. AirNow — Protect Your Pets from Wildfire Smoke
2. UC Davis Environmental Health Sciences — Protecting Animals & Pets
3. CDC — Wildfires: Safety Guidelines (Pets included)
4. Corsi-Rosenthal Foundation — How to Build a DIY Air Cleaner

Related on Pawfect Cat Care: Heat Safety • Wet vs Dry Cat Food • Urinary Health • Cat Anxiety • Why Is My Cat Meowing So Much?