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• Posted March 4, 2026

Your Furry Roommate May Be Affecting The Air You Breathe

Dogs may bring more than companionship into a home: They can also affect the air we breathe indoors, a new study shows.

Researchers found that dogs release airborne particles, gases and microbes that can affect indoor air quality. In some cases, the levels were similar to, and sometimes higher than, what humans release.

The findings were published last month in the journal Environmental Science & Technology.

“By quantifying what dogs add to indoor air, we can build more realistic indoor air quality and exposure models and better inform ventilation strategies — without blaming pets or discouraging pet ownership," study author Dusan Licina, a researcher at the Human-Oriented Built Environment Laboratory in Lausanne, Switzerland, said in a news release.

To study the issue, researchers examined several dogs in a controlled lab setting and compared their emissions to those produced by their owners.

The team tested four small dogs, all Chihuahuas, and three large dogs, including a Tibetan Mastiff, a Newfoundland and an English Mastiff. 

Each group was studied separately in a room with its owner. Scientists measured gases, tiny particles in the air and microbes.

Large dogs released carbon dioxide and ammonia at levels similar to humans, the study found, and at much higher levels than small dogs.

Small and large dogs alike also released more airborne particles than their owners. The smallest dogs produced the most particles, likely because they were more active during testing.

When it came to microbes, the bigger pooches had the biggest impact. They released the highest levels of bacteria and fungi into the air, many of which appeared to come from outdoors.

That means dogs may bring outside microbes into the home and change the mix of microorganisms indoors.

The researchers say the findings suggest dogs can influence indoor air quality as much as humans — and sometimes even more.

Licina noted that dogs may act like mobile transport vectors, meaning they carry particles and microbes from outside environments into indoor spaces.

The scientists said future studies will look at how other pets such as cats, rabbits and rodents, may affect indoor air.

They said pets should be considered when designing ventilation systems for homes.

More information

PNAS has more on air pollution and pet health.

SOURCE: American Chemical Society, news release, March 3, 2026