Harmful particles that originate inside and tend to stay inside become indoor air pollution. The most common culprits are dust, which is 70% percent dead skin, pet dander, mold spores, bacteria, microscopic organisms, smoke, and chemicals from cleaning products. Certain rooms contain higher amounts of certain allergens, but even offices and the interior of cars are susceptible to indoor pollution. None of these spaces have adequate ventilation to freshen air, and all of them have unnecessarily high humidity.
The top indoor allergen is dust mite protein, created by mite carcasses and excretion. As with most allergies, exposure to dust mites can cause congestion, red and itchy eyes, itchy skin, or respiratory problems. These mites rely on a moist, warm environment with lots of dust; conditions that are common in most people's living and work places. Millions of mites are sustained by water vapor and nutrients from our skin flakes and bacteria. The bedroom is the most affected as there are plenty of cloth surfaces for the tiny creatures to live, and there is lots of humidity due to people's breathing. To this end, a dehumidifier can dramatically reduce the moisture in a room to 30-50% and impact dust mite population.
The most effective strategy against all this pollution is still old-fashioned cleaning as a preventative measure. Keep moist surfaces or standing water to a minimum in the kitchen. Vacuum, wipe, dust, or mop floors and hard surfaces frequently. Wash bedding and linens in very hot water, which will kill some of the dust mites. Replace pillows, especially children's pillows, yearly if they cannot be laundered. Consider installing wood or tile floors; they harbor less mites and dust than carpets and rugs.
Air circulation devices, such as centralized heating and air conditioning, fans, air purifiers, or dehumidifiers can serve as collection areas for dust and mildew if not properly maintained. All these appliances have filters, ducts, or screens that must be cleaned or replaced regularly. Make sure all the ventilating outlets to your house are clean, including window screens.
Other purification tools include air ionizers, vacuums equipped with HEPA (High Efficiency Particle Arresting) filtration, HEPA air purifiers, and carbon filters. When indoor air can be five to ten times as polluted as outdoor air, it is important to take every preventative and corrective measure available. Even house plants, which recycle carbon dioxide into oxygen, help clean air.