Indoor air quality can be significantly impacted by the presence of dogs, according to a new study released this week by the École Polytechnique Fédérale de Lausanne in Switzerland. Researchers found a notable increase in particles and microorganisms in environments with canine companions.
The research took place in a highly controlled environmental chamber in Friburgo, Germany, involving three large dogs and four tiny dogs, including Chihuahuas. The chamber maintained constant temperature and humidity while continuously filtering the air, allowing scientists to attribute any changes in air quality solely to the animals’ presence.
Everyday actions such as shaking, scratching, and receiving affection cause dogs to release relatively large particles into the air, including dust, pollen, plant debris, and microorganisms, the scientists determined. Sensors registered bursts of indoor air pollution each time the animals moved.
The study too revealed that larger dogs can emit two to four times more microorganisms than a person in the same room.
Balancing Risks and Benefits: Dogs’ Impact on Indoor Air Health and Chemistry
Despite these findings, researchers emphasize that the effects aren’t entirely negative. “This high level of microbial diversity isn’t necessarily bad news. Some studies suggest that exposure to a variety of microbes can stimulate the development of the immune system, especially in children,” explained Professor Dusan Licina, a researcher at the laboratory where the study was conducted.
However, Licina cautioned that the actual impact of these microorganisms on human health remains uncertain and can vary from person to person.
The study also established that dogs generate 40% fewer ozone derivatives than humans. In people, this gas reacts with skin fats like squalene, producing chemical compounds such as aldehydes, ketones, and other small particles.
While dogs don’t naturally produce squalene, the substance can adhere to their skin after contact with humans and subsequently react with ozone, creating chemical byproducts.
Regarding other gases, scientists concluded that dogs emit similar amounts of carbon dioxide (CO₂) and ammonia as humans. This is as, although they release proportionally more ammonia per unit of CO₂, they tend to spend more time at rest and breathe more slowly.
“A large dog, such as a Mastiff or Newfoundland, can produce as much CO₂ as an adult human at rest,” the researchers detailed.
