It might not be pleasant to think about, but the air we breathe often is contaminated with both particles and gases. And clearing the air of these toxins often requires different removal or purification strategies.

Particles include: Dust, pollen, mold, pet dander, textile fibers, skin flakes and particles from sources such as industrial plants and smoke.

Gases include: A myriad of airborne substances including carbon dioxide, formaldehyde, volatile organic compounds (VOCs, small molecules that evaporate from products and surfaces) and fragrances from cleaning products, colognes and more.

In general, indoor air is the main route of exposure to contaminants. “[Each] day, individuals ingest about two pounds of food, four pounds of liquid and 30 pounds of air,” according to Michael A. Berry, PhD, author of Protecting the Built Environment: Cleaning for Health.

Unfortunately, dirty air can have significant effects on your health. For example, studies have strongly linked air pollution to various health conditions, including heart disease, asthma and depression.

But since airborne pollutants occur in complex mixtures, it is hard to find a single “smoking gun.” Contaminant mixtures, rather than specific pollutants, likely contribute to numerous ailments.

According to the Environmental Protection Agency, there are three basic preventive or precautionary steps, in order of importance…

  1. Remove sources
  2. Ventilate
  3. Purify the air

Remove Sources

Particle source removal should include generous entry mats to remove dusts before they can get indoors and become airborne.

It also includes frequent vacuuming (using a vacuum that actually contains the dust) and dusting (using a dusting method that removes particles, such as a damp cloth or microfiber towel).

Gas removal includes getting rid of scented candles, fragranced cleaning products, dryer sheets and more. According to research by Anne Steinemann, PhD, of University of Melbourne, Australia, published in Air Quality, Atmosphere, & Health, “34.7 % of the population reported health problems, such as migraine headaches and respiratory difficulties, when exposed to fragranced products.”


Since indoor air generally is more polluted than outdoor air, especially with gaseous pollutants such as VOCs, bringing fresh air indoors is the next step to “cleaning” your air. Outdoor air dilutes the level of indoor pollutants.

Helpful: If you don’t have an attic fan to draw outdoor air in, place a box fan facing out in front of an open window and then open a window on the opposite side of the house.

Purify the Air

Air purifiers also can help. What’s more, these devices can be especially beneficial for people with allergies or chemical sensitivities. What’s right for you?

Air purifiers are available in portable devices designed for individual rooms or whole-house units that are built into your central air-conditioning or forced-air heating system (aka, the HVAC unit). If you want air purification in your entire home, it may be cost effective if the air ductwork is built in. However, most people get good results in the areas where they spend the most time with one or more portable units.

Important: Because there are so many options when buying a portable air purifier, it’s easy to make mistakes that end up costing you money and/or prevent you from getting the pollution-fighting features you really need…

Mistake 1: Getting the wrong type of air purifier. There are two main types of air purifiers—units that remove particles (such as dust, pollen, mold and pet dander) and those that remove gases/odors (such as paint fumes and formaldehyde from glue in wood furniture). Some units remove both particles and gases/odors.

To determine which type of air purifier you need, ask yourself, What am I trying to get rid of? Allergy and asthma sufferers often will want an air purifier that removes particles. Someone who is chemically sensitive will want to eliminate gases and odors.

Air-cleaning devices designed to capture tiny particles from the air typically use high-efficiency particulate air (HEPA) technology. HEPA filters remove 99.97% of particles as small as 0.3 microns. For reference, a single hair is about 70 microns wide.

Air purifiers designed to remove gases and odors typically use activated charcoal or other material that binds to the pollutants. If you want to get rid of particles and gases, look for a purifier with both HEPA technology as well as a material such as activated carbon.

Other options include electrostatic precipitators, which charge airborne particles and cause them to stick to an oppositely charged plate. Similarly, ionizers charge the airstream, causing charged particles to adhere to a filter or other surface.

An interesting development is ionizing air purifiers that install within HVAC ducts. Working in tandem with existing HVAC filtration systems, they both enhance particulate removal and reduce VOC levels and airborne pathogens. The ionization apparently causes dust particles to clump, making them easier to remove by the HVAC’s filter media. The units also have ozone-capturing technology to minimize ozone in the space both from the ionization process and other sources such as laser printers, outdoor air pollution and more. This technology, such as from IONaer, seems promising for vulnerable populations because it also reduces airborne flu virus.

If you live with a person who is chronically ill or who has a compromised immune system, you might also opt for an air purifier that uses ultraviolet (UV-C) light technology. This type of air purifier, frequently used in hospitals, destroys germs such as certain types of viruses and bacteria. The “C” stands for the frequency of UV light that kills germs.

Mistake 2: Not checking a unit’s efficiency and certification. A critical factor when selecting an air purifier is the device’s clean air delivery rate (CADR), established by the Association of Home Appliance Manufacturers (AHAM). This numerical rating measures how quickly a portable air purifier can remove particles such as pollen, dust and tobacco smoke from a certain square-foot dimension. Specifically, it measures how much air is moving through the filter and the volume of filtered air delivered by an air purifier.

The higher the CADR number, the better. Maximum CADR values are 450 for pollen and smoke and 400 for dust. The AHAM website has a list of certified air purifiers with their CADR values.

Your room size helps determine the most appropriate CADR. If there’s, say, a smoker in the home, the AHAM recommends looking for a unit with a “tobacco smoke CADR” of at least two-thirds of your room’s area. For example, a 10-foot by 12-foot room (120 square feet) would require a CADR of at least 80.

If you have allergies or asthma, you may also want to visit the site of the Asthma and Allergy Friendly Certification Program to see whether the air purifier you’re considering has been certified by the Asthma and Allergy Foundation of America (AAFA).

Mistake 3: Not placing the air purifier in the right location. It sounds obvious, but the key to achieving the cleanest air possible is to ensure that the polluted air actually passes through the filter. Many contaminants will never reach a small device that is located, for example, in the corner of your bedroom.

For the best coverage, you may wish to purchase several air purifiers, depending on how big an area they can clean—or at least shut the door to the room with the single air purifier to keep out nonfiltered air.

Mistake 4: Not changing the filter often enough. Manufacturers provide a schedule of recommended times to change the filter. Carefully follow these recommendations to keep your unit running in peak condition. Dirty filters lose effectiveness over time, and this could result in higher electricity costs if the air purifier has to run for longer periods of time to clean the air.

If your air is especially dirty, you might need to replace the filter every few months (or more often). If it’s reasonably clean, once a year (or less often) may be sufficient. Many units come with filter-change sensors that alert you when they’re clogged, often based on airflow reduction.