Humidity refers to the amount of water vapor present in the air. This invisible gas is a natural component of the atmosphere, influencing various environmental conditions. Relative humidity, a common measurement, indicates the amount of moisture in the air compared to the maximum it can hold at a specific temperature, expressed as a percentage.
When the air contains a small amount of water vapor, it is considered to have low humidity, typically below 40% relative humidity. Dry conditions often result from cold outdoor air, which holds less moisture, or heating systems that dry indoor air. These dry environments impact living organisms and objects within a home.
Impact on Human Health
Low humidity significantly affects the human body by drying out mucous membranes. The respiratory system is susceptible, as dry nasal passages and throat membranes become irritated and less effective at trapping airborne particles like bacteria and viruses. This diminished defense increases susceptibility to common illnesses like colds and influenza. Viruses also survive longer in drier air, contributing to their spread.
Skin is prone to issues when humidity is low, leading to dryness, flakiness, and itching. Conditions like eczema or psoriasis can worsen, causing discomfort and pain. Low humidity draws moisture from the skin, potentially creating small cracks that may serve as entry points for infection.
Eyes experience irritation and dryness due to increased tear evaporation in low humidity. This rapid evaporation disrupts the natural moisture balance for proper eye function. Prolonged exposure to dry air also contributes to nasal congestion by affecting the cooling process within nasal passages, irritating sinus membranes.
Low humidity influences overall well-being. Dry air leads to discomfort and may disrupt sleep quality, potentially causing snoring or making individuals wake up feeling less refreshed. Maintaining an indoor relative humidity level between 40% and 60% is beneficial for human health and comfort.
Effects on Plants and Animals
For plants, dry air accelerates transpiration, the process of water evaporating from leaves, leading to increased water loss. This can cause leaves to wilt, turn brown at the tips, or stunt growth as the plant struggles to retain moisture.
Soil around plants also dries out more quickly in low humidity, requiring more frequent watering to compensate for accelerated evaporation. Without adequate moisture, plants may not absorb nutrients efficiently, compromising their health. This makes maintaining optimal growing conditions challenging.
Pets can suffer from dry skin and irritation in low humidity. Their fur can also build up static electricity, leading to minor shocks when touched. Some animals may experience dry eyes or respiratory irritation, especially if they have pre-existing respiratory sensitivities. Ensuring sufficient humidity contributes to the comfort and health of household animals.
Influence on Materials and Surroundings
Low humidity affects the structural integrity of indoor spaces, impacting various materials. Wood, common in furniture, flooring, and musical instruments, is vulnerable to dry air. As moisture evaporates from wood, it can shrink, leading to cracking, warping, or joint separation. This damage can be irreversible, diminishing the lifespan and appearance of wooden items.
Static electricity becomes more prevalent in low humidity because less moisture in the air conducts away electrical charges. This can result in frequent static shocks when touching objects or people. Such static discharge also poses a risk to sensitive electronics, potentially damaging internal components.
Air quality within a dry environment is also affected. Low humidity allows airborne dust, allergens, and other microscopic particles to remain suspended longer. With less moisture, these particles are less likely to settle, increasing exposure to irritants and affecting indoor air cleanliness. This can exacerbate respiratory discomfort for individuals sensitive to airborne pollutants.