References and Sources
[1] Bougault, V. et al. (2025). “Air quality, respiratory health and performance: a summary of the IOC consensus subgroup narrative review on Acute Respiratory Illness in Athletes.” British Journal of Sports Medicine, 59(7), 480-490. See also: Rundell, K.W. (2012). “Effect of air pollution on athlete health and performance.” British Journal of Sports Medicine, 46(6), 407-412. Research confirms air pollution adversely affects athletic performance during both training and competition, with pollutants causing oxidative damage and inflammation in the airways.
[2] The average adult respiratory rate at rest is 12 to 20 breaths per minute. Sources: American Lung Association, “Understanding Vital Signs: The Importance of Your Respiratory Rate”; Cleveland Clinic, “Vital Signs”; Physiopedia, “Respiratory Rate.” At an average of approximately 15 breaths per minute, this yields roughly 21,600 breaths per day. The figure of 20,000 is the commonly cited rounded estimate.
[3] U.S. Environmental Protection Agency. “Sources of Indoor Particulate Matter (PM).” EPA.gov. The EPA identifies indoor PM sources including biological contaminants (mold spores, pet dander, dust mites), particles from cooking and cleaning, consumer products, and outdoor PM that infiltrates buildings.
[4] U.S. Environmental Protection Agency. “The Inside Story: A Guide to Indoor Air Quality.” EPA.gov. The EPA states that indoor levels of pollutants may be two to five times, and occasionally more than 100 times, higher than outdoor levels.
[5] Klepeis, N.E. et al. (2001). “The National Human Activity Pattern Survey (NHAPS): A Resource for Assessing Exposure to Environmental Pollutants.” Journal of Exposure Science and Environmental Epidemiology, 11, 231-252.
[6] U.S. EPA. “What is a HEPA filter?” and “Guide to Air Cleaners in the Home.” EPA.gov. HEPA (High Efficiency Particulate Air) filters capture particles by forcing air through a fine mesh. The filter’s effectiveness depends on air being drawn through the filtration medium.
[7] U.S. EPA. “Guide to Air Cleaners in the Home.” EPA.gov. Standard mechanical filters, including HEPA, are designed to remove particles. They do not remove gaseous pollutants such as volatile organic compounds (VOCs) including formaldehyde, benzene, and other chemicals.
[8] Heard, D.E. & Pilling, M.J. (2003). “Measurement of OH and HO2 in the Troposphere.” Chemical Reviews, 103(12), 5163-5198. Hydroxyl radicals are widely recognized as the primary oxidizing agent responsible for the removal of most trace gases and pollutants in the troposphere.
[9] WellisAir patented hydroxyl generator technology. The oxidation process breaks down organic contaminants, with the primary end products being trace quantities of water vapor (H₂O) and carbon dioxide (CO₂). See also: Weschler, C.J. (2011). “Chemistry in indoor environments.” Environmental Science & Technology, 45(6), 2270-2276.
[10] Ural, B.B. et al. (2022). “Inhaled particulate accumulation with age impairs immune function and architecture of the lung-associated lymph nodes.” Nature Medicine, 28, 2622-2632. Columbia University Irving Medical Center. The study found that inhaled particles from environmental pollutants accumulate over decades inside immune cells in lymph nodes associated with the lung, eventually weakening the cells’ ability to fight respiratory infections.
[11] Glencross, D.A. et al. (2020). “Air pollution and its effects on the immune system.” Free Radical Biology and Medicine, 151, 56-68. The review confirms that a well-functioning immune system is vital for a healthy body, and that ambient pollutants disrupt immune homeostasis, potentially leading to increased susceptibility to infections, allergies, and autoimmune conditions.