Low humidity, at levels under 35 percent, can affect your comfort and health during the cold months of winter, in geographic regions containing no large bodies of water and in enclosed environments that make heavy use of air conditioning, according to the Allergy Be Gone website. When humidity is low, threats to comfort, allergies, asthma, immune systems and mortality ensue.
Humans are particularly sensitive to humidity and its changes. The drier the air becomes, the more moisture it pulls from whatever sources are available to it – and that includes your body. During cold winter months, using heaters inside lowers humidity even more, causing more moisture to evaporate from your skin into the air and leave your skin even drier. As a result, sensitive areas like your lips and hands may crack, peel, become irritated, and even become infected, reports the National Health Museum. Additionally, as moisture leaves your body due to low humidity during cold months, you perceive lower than actual temperatures and feel even colder that it actually is, which also drives up energy costs from using heaters to feel more comfortable indoors.
Low humidity is largely responsible for high instances of illness during winter, partly because germs and bacteria thrive in low humidity. Additionally, your body loses moisture through your skin when there's not enough moisture in the air, rendering you more susceptible to germs and bacteria. In particular, the mucous membranes in your throat and nasal passageways become dehydrated, and thus stressed and less capable of serving as your body's primary barrier to airborne infections that cause colds and flus. Normally, those mucuous membranes filter the air allowed into your body by fending off threatening microbes and viruses. Yet when they become dry, itchy and cracked, wide open passages are created to grant entrance to the usually shielded germs and bacteria that cause sore throats and illness.
Breathing and Allergies
Along with germs and bacteria that thrive in low humidity environments and enter susceptible bodies through unguarded mucous membranes, mold, fungal spores, dust mites and other allergens in the home dry out and float into the air to be inhaled by allergy and asthma sufferers. As the air pulls moisture from the skin of individuals who already suffer from skin allergies, those allergies are further excerbated. The dry, cracked skin resulting from moisture's evaporation from the nasal passageways and upper respiratory tract can also lead to spontaneous nosebleeds, breathing difficulties and snoring.
Air humidifiers can help control and maintain healthy in-home moisture levels of 30 to 35 percent throughout the year to help defend against the health dangers of low humidity. Other methods of providing more moisture to the air around you is to fill bathtubs with water, place containers of water in your rooms, or boil water on the stove to provide the air with additional sources of moisture when humidity is low. In addition, people should avoid excessive use of air conditioning, which can induce the same dangerous effects.