Asthma is a chronic lung disease that affects almost 26 million Americans, including 7.1 million children. Asthma narrows the airways that deliver oxygen to the lungs, making breathing difficult. Symptoms are triggered by exposure to airborne particles and other environmental contaminants. Unlike other lung-related diseases such as bronchitis and emphysema, asthma is reversible. However, inflammation can cause long-term damage to the lungs, so symptoms must be controlled or avoided.

Every year, asthma symptoms prompt more than 15 million physician and hospital outpatient visits and 2 million emergency department visits (1). Statistics show that hospital visits for asthma peak in colder months, and there are at least two reasons why:

1. Changes in temperature, especially rapid decreases in temperature, affect lung function.
2. The first seasonal uses of heating systemskick up dust and other particles that trigger allergy and asthma symptoms.

Cold weather and asthma

Rapid changes in the weather, especially the rapid onset of cold weather, are directly responsible for decreased lung function in asthmatics. Cold, dry air irritates the tissue in the lungs of an asthmatic, causing bronchospasms. These spasms, or constrictions, occur around the bronchial tubes and make breathing difficult. Often, excess mucus is also produced, further limiting breathing and causing wheezing and coughing.

The combination of exercise and breathing cold air can trigger asthma flare-ups, making outdoor exercise difficult. In some winter weather systems such as inversions, increased levels of ozone further aggravate asthma symptoms.

Indoor heating systems and asthma

The first uses of indoor heating systems during the autumn and winter months can trigger asthma symptoms. In a study of asthma hospital admissions in New York City and other urban areas, the American Thoracic Society found that emergency clinic admissions for asthma increase with the first seasonal uses of indoor heating (2). The study suggested that increases in admissions are related to the presence of airborne dust and other pollutants stirred up and into the air from heating system ducts.

Contaminants found inside heating ductwork typically include dust and pollution particles along with mold, bacteria, pollen, dust mites, pet dander and other contaminants. All of these easily become airborne when the heating system is fired up, and all of them are asthma triggers.

3 Tips for dealing with asthma in cold weather

1. In cold weather, breathing through the nose rather than the mouth may help reduce asthma symptoms caused by cold air, according to the American Lung Association Covering the nose or mouth with a scarf may also help. (3)
2. Get air ducts in the home professionally cleaned. The U.S. Environmental Protection Agency suggests interviewing potential service providers to ensure they comply with national air duct cleaning standards. If your ducts are made of – or lined with – fiberglass, the provider should also comply with recommendations from the North American Insulation Manufacturers Association (4)(5).
3. A high-performance whole-house air filtration system such as the PerfectPro will virtually eliminate dust and other particles from the heating ducts. The Perfect 16 includes a lifetime clean-duct guarantee. A whole-house air filtration system will also help control seasonal airborne contaminants that are asthma triggers, such as air pollution or wood smoke from fireplaces. For homes without a central forced-air heating and cooling systems, high-performance room air purifiers such as the HealthPro Plus and Atem X can help eliminate airborne asthma triggers.