Indoor Air Pollution and Respiratory Disease in Pets

Potential indoor airborne hazards for pets are similar to those that affect people, including tobacco smoke, incense, cooking fumes, cleaning chemicals, and kerosene and coal combustion.

Investigators in Taiwan recently examined this topic in detail to see if common air pollutants influence the development of respiratory disease in pet dogs and cats.

Study Design

Dogs and cats presenting to the National Taiwan University Veterinary Hospital were enrolled in the prospective study over a 12-month period. All participants lived primarily indoors, were at least 1 year old, and were assigned to the disease or control group based on the presence and history of respiratory signs.

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Owners completed a written questionnaire describing the air pollutants in the home (eg, tobacco smoke, incense, paint, cooking fumes) as well as the incidence, duration, and characteristics of respiratory illness in their pets. Researchers also used an air quality monitor to sample concentrations of particulates measuring 2.5 μm or less (PM 2.5) in participating homes. The PM 2.5 level is used commonly as an estimator of air quality. During a single home visit, readings were taken in the 5 areas of the home most commonly frequented by participating pets and then averaged for final analysis.

An additional 146 hospital clients completed questionnaires to estimate the prevalence of pet respiratory signs and various airborne pollutants in the home.

Results

Eighty-three dogs and 64 cats with respiratory disease were enrolled in the study, while 38 dogs and 17 cats served as controls. Client responses indicated that frequent exposure to cooking fumes, secondhand smoke, incense burning, and household chemicals occurred in 73%, 33%, 17%, and 12% of homes, respectively. The most common diagnoses in dogs were lower respiratory tract disease, tracheal collapse, and upper airway disease. Cats were diagnosed most frequently with lower airway disease, upper airway disease, and pneumonia.

Exposure to secondhand smoke, cooking fumes, and household chemicals was not significantly different between pets with and without respiratory disease; however, burning of incense correlated with an increased prevalence of respiratory disease in dogs.

Unacceptably high PM 2.5 concentrations were found in 48% and 53% of households with pet dogs and cats, respectively. High levels were associated consistently with respiratory disease in cats but not in dogs. The investigators did note that several households of dogs with respiratory disease were statistical outliers with “extremely high” PM 2.5 concentrations.

According to logistic regression analysis, unacceptably high PM 2.5 concentration and lower ambient temperature were predictors of feline respiratory disease. However, signalment factors including older age, smaller body size, and higher body condition score were more important predictors of respiratory disease in dogs than were air pollutants.

Major Conclusions

High concentration of fine air particles in the examined households was significantly associated with respiratory disease in cats, suggesting potentially harmful effects of indoor air pollutants on feline patients. Canine respiratory disease was more significantly affected by signalment factors than with pollutant exposure.

Dr. Stilwell received her DVM from Auburn University, followed by a MS in fisheries and aquatic sciences and a PhD in veterinary medical sciences from the University of Florida. She provides freelance medical writing and aquatic veterinary consulting services through her business, Seastar Communications and Consulting.