Indoor air quality (IAQ) describes the nature of the air within and around buildings. Since the air inside a home can often be more polluted than the air outside due to trapped contaminants, improving IAQ is important for overall wellness and respiratory health. While mechanical air purifiers are a common solution, they can be costly or inaccessible for many households.
Maximizing Natural Ventilation
Natural ventilation relies on the pressure difference between indoor and outdoor air to facilitate exchange. The most powerful technique is cross-ventilation, which involves creating openings on opposite sides of a space to allow air to flow freely across the room. This harnesses wind-driven force, pushing stale indoor air out.
Air movement is maximized when the inlet and outlet are positioned to create a direct path for the breeze. Strategically opening windows at different heights can also utilize stack ventilation. Warmer indoor air rises and escapes through higher openings, drawing cooler, fresh air in through lower ones.
Timing the air exchange is important. Early mornings and late evenings are the optimal times to open windows when outside temperatures are cooler and pollen counts are lower. Night flushing involves opening windows overnight to circulate cool air, reducing reliance on air conditioning.
Simple electric fans can be used to direct and accelerate airflow, such as positioning a box fan in a window to draw air in or exhaust air out. Kitchen and bathroom exhaust fans should be used to pull moisture and cooking fumes directly outside before they distribute pollutants throughout the home.
Using Houseplants for Biological Filtration
Certain common houseplants employ phytoremediation, where the plant and its associated soil microbes work together to decontaminate the air. Plants absorb volatile organic compounds (VOCs) like formaldehyde and benzene through their leaves and metabolize them. The microorganisms living in the potting soil’s root zone, or rhizosphere, also contribute by breaking down the chemical compounds the plant absorbs.
Plants with dense foliage, such as the Snake Plant and Spider Plant, are often cited for their ability to remove toxins. However, it is important to manage expectations regarding the extent of air purification. Studies show that achieving an effect comparable to mechanical filtration requires a significant number of plants.
Natural ventilation exchanges air much faster than plants can filter it. Therefore, houseplants are best utilized as a supplementary method that offers psychological benefits and minor filtration, rather than a primary purification system.
Controlling Indoor Pollutant Sources
The most effective approach to air purification is source control: proactively stopping pollutants from entering the air. Many common household items, including paints, adhesives, and cleaning products, emit VOCs, which are chemicals that can irritate the respiratory system. Choosing low-VOC or zero-VOC paints and finishes for home projects significantly reduces the off-gassing of these chemicals.
Routine and targeted cleaning prevents particulate matter from becoming airborne. Dusting and vacuuming surfaces regularly removes accumulated allergens that can easily be resuspended in the air by foot traffic.
Maintaining the humidity level within the home prevents biological pollutants, as mold and mildew thrive in damp environments. Using a dehumidifier in moisture-prone areas like basements and bathrooms to keep relative humidity between 30% and 50% prevents the growth of mold spores.
Removing shoes at the entryway prevents outdoor contaminants, such as pollen and soil-borne residues, from being tracked throughout the living space.
Harnessing Passive Air Absorbers
Certain non-living, porous materials can passively absorb odor molecules and chemical vapors from the surrounding air. Activated charcoal, often made from bamboo or coconut shells, is highly effective due to its immense surface area and micro-porous structure. This material works through adsorption, where pollutants stick to the charcoal’s surface. It can be placed in breathable cloth bags for use in small, enclosed areas like closets, refrigerators, or storage containers.
Baking soda, or sodium bicarbonate, is another effective and inexpensive household odor neutralizer. Its mildly alkaline properties allow it to absorb and neutralize odors. Placing an open container of baking soda in a problem area, such as a pantry or a small cupboard, helps to trap ambient smells and some moisture.