As if sweaty machines weren’t enough, here’s something else that may add to your gym’s ick factor: poor air quality. The typical indoor workout facility contains microscopic airborne pollutants, according to a new study in Building and Environment.
Researchers placed air quality monitors in 11 indoor gyms in Portugal. (The gyms were similar to the average gym in the United States.) The monitors measured levels of common air pollutants, including carbon dioxide, carbon monoxide, particulate matter—microscopic particles composed of metals, sulfate, and chloride, among other chemicals—and volatile organic compounds, which include chemicals likes acetone and formaldehyde. Measurements were taken for about two hours per day during each gym’s peak times.