Many air pollutants are notorious for their ability to trigger allergic reactions such as rhinitis or even asthma attacks, and their concentrations increase when no efforts are carried out to preserve indoor air quality. The following are some of the most common allergens found inside built environments:
- Volatile organic compounds (VOCs)
- Dust mites
- Pet dander
Indoor air quality can be improved through active strategies such as air filtering, or by adopting habits that help reduce the ingress or release of harmful compounds. Both approaches can be combined for greater effect.
Volatile Organic Compounds (VOCs)
VOCs are a broad category of compounds that have one property in common: they have a high vapor pressure and a low boiling point, which causes them to evaporate or sublimate spontaneously, getting mixed with indoor air.
Although not all VOCs are harmful for humans, a significant portion of them has been linked with health issues, especially those released by paints, solvents, artificial fragrances and cleaning agents. The effects of VOCs can range from relatively mild ailments such as nose irritation, to more severe conditions such as liver damage and cancer.
The Environmental Protection Agency has determined that indoor VOC levels are 2 to 5 times higher than outdoor levels on average, and may be up to 1,000 times higher during certain activities such as painting. Some recommended strategies to control VOC concentrations are the following:
- Make sure that adequate ventilation is provided for any activities where VOCs will be emitted in large quantities.
- Avoid the indoor storage of open containers with VOC-emitting substances, and don’t keep a large stock of these compounds.
- Read product labels in depth before using fragrances, cleaning agents or similar products. Some products are not intended for indoor use, but the instructions are often overlooked.
It is important to note that research on VOCs and their impact on human health is relatively new, and most existing standards are only applicable in industrial settings. However, the negative effects on human health are real – they are simply not understood in depth yet.
Mold is a type of fungus that is notoriously difficult to eliminate from indoor environments, and its spores are practically impossible to remove completely. The key for keeping mold under control is eliminating the main condition necessary for its growth: humidity. This is the main reason why mold growth is especially common in kitchens, bathrooms, laundry areas, basements and other areas with plenty of moisture.
Although mold is static, it reproduces through airborne spores, and these can trigger allergic reactions in sensitive individuals when inhaled, or even asthma attacks if they reach the lungs. Very large amounts of spores may be released at once if a moldy surface or piece of equipment is moved suddenly, so exercise extra caution if you are moving furniture that has been in the same place for a long time.
Among all common household allergens, mold is among the least difficult to detect due to its color and smell. Keep in mind, however, that mold often grows in humid places that are out of sight. Make sure your air conditioning and humidifying equipment gets serviced frequently to prevent the accumulation of mold within. Moldy HVAC equipment can be very problematic because it continuously spreads spores.
When mold grows on smooth surfaces, you can clean it directly with water and detergent, but make sure you wear a filter mask to avoid inhaling spores. There are also situations where the cleaning process is more complex, for example if mold grows inside air ducts, and in those cases hiring professional services is recommended. Porous objects with severe mold growth are very difficult to clean and must often be discarded.
Dust mites are too small to be detected with human vision, but they are one of the most common causes of allergic reactions in residential settings. Like mold, dust mites are strongly dependent on humidity to survive, and they generally die when relative humidity drops below 50 percent.
Dust mites are most commonly found in beds, furniture and carpets, and they are small enough to float in the air when dust particles are disturbed. Allergic reactions are especially common after cleaning, since there is plenty of airborne dust.
One of the best recommendations to prevent spreading dust mites when vacuum cleaning is to use a high-efficiency particulate arrestance (HEPA) filter. These filters can capture 99.97% of particles with a size of 0.3 microns, and can be very useful for keeping dust mites under control.
Pollen is released by plants during their flowering season, and it is recommended that you keep your windows closed when outdoor pollen concentrations are high. The National Allergy Bureau runs a site where you can view pollen concentration levels by city, updated every 24 hours. Checking the pollen levels at your location is recommended if you are susceptible.
Another recommendation to control pollen is avoiding indoor flowering plants. Many household plants are beneficial for indoor air quality, filtering out VOCs and other pollutants, but the plant defeats its own purpose if it releases pollen constantly.
Pet dander is a term used to describe particles that are shed by animals with fur or feathers, which includes dead skin cells. These particles are small enough to be spread by the air or to become impregnated in clothes, and they also provide a source of food for dust mites, another common allergy trigger. If you are planning to buy a pet, make sure you are not allergic to pet dander. If this is your case, consider pets without fur or feathers, such as fish.
Like in the case of dust mites, it helps to clean your furniture and carpets frequently, using a vacuum cleaner equipped with a HEPA filter. Also, make sure you change your clothes whenever you have been exposed to animals, to avoid spreading dander throughout your house.
General Recommendations to Reduce Indoor Allergen Concentration
Each type of allergen is different, but several strategies are effective across the board. The recommendations provided below will allow you to reduce allergen concentrations in your household significantly:
- A well-designed ventilation system: Building codes establish minimum airflow requirements for indoor environments, ensuring that air is constantly renewed with outdoor air, which has lower pollutant concentrations even in urban settings.
- Air filtering: If you equip your HVAC installation with HEPA filters, you can capture most airborne particles. As stated before, HEPA filters have a 99.97% efficiency for particles with diameters as small as 0.3 microns.
- Humidity control:Mold and dust mites both thrive with humidity, and their populations are reduced drastically when you reduce relative humidity below 50 percent. Use air dehumidifiers if your HVAC system is unable to control humidity on its own.
- Safer Choice Label by EPA: Purchase cleaning products with the Safer Choice label, since these have been approved by EPA for having safer chemical compositions than conventional and non-labeled cleaning agents.
- Aromatic plants: These are an alternative to artificial fragrances, with the difference that they will not pollute your indoor air with VOCs. An additional advantage of plants is that they filter many allergens out of the air, including mold spores and VOCs.
Indoor air quality testing has a relatively low cost, especially when you consider the medical expenses avoided by controlling the presence of harmful compounds. If you use basic testing kits, you will probably spend under $100; while a professional evaluation generally costs a few hundred dollars, ranging from $300 to $500 on average.