Is The MERV Rating for An Air Filter Important for Allergies?

Filters Fast MERV 11 Air and Furnace Filter

Air filters remove airborne allergens and pollutants such as dust, mold, pollen, pet dander and bacteria from your indoor air. There is a vast array of air filters with different levels of measurement for determining the concentration of different particle sizes, usually by weight or count. This measurement of performance for air filters is called Minimum Efficiency Reporting Value (or a MERV rating). MERV ratings come from ANSI/ASHRAE Standard 52.2: Method of Testing General Ventilation Air Cleaning Devices for Removal Efficiency by Particle Size.

ANSI, the American National Standards Institute, accredits and ensures that the characteristics and performance of products are consistent with terms, definitions and testing of products. ASHRAE, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, develops standards for its members and other professionals involved with refrigeration processes and the maintenance and design of indoor environments.

 A MERV rating is based on three composite, average removal efficiency points for particles. Categories range from 1 (very low) to 16 (very high). The higher the rating, the more efficient your air filter will help to reduce indoor airborne allergens, pollutants and contaminants.

 MERV 1 to 4 filters provides minimal filtration. These filters have to be replaced quite frequently and are typically disposable fiberglass or synthetic panel filters within a cardboard frame. These filters capture up to 80% of airborne particles as small as 10 microns. MERV 5 to 8 filters are good for capturing dust and mold spores. These filters have to be replaced, depending on usage, every 3 months. MERV 8 replacement air filters  will reduce pollen, pet dander, dust and other contaminants as small as 3.0 microns.

 MERV 9 to 12 furnace air filters capture up to 95% of airborne particles and contaminants like pollen, dust mites and mold spores, as small as 1.0 microns. These filters come in a deep pleated, boxed media or bag filters, which are some of the most efficient filters used in homes and commercial buildings.

 MERV 13 to 16 air filters will trap up to 98% of airborne allergens and pollutants such as bacteria, tobacco smoke, cooking oil and droplet nuclei, as small as 0.3 microns. Filtration should be applied to process both return and outside air that is delivered as supply air.  Finding the best-rated air filter for your particular need or application will help to keep your air clean and fresh. Don’t forget to change your air filter as recommended and especially when you change your clocks to Standard Time or Daylight Savings Time.

Dandruff Improves Indoor Air Pollution

household dustHumans shed their entire layer of skin every 2-4 weeks. Skin flakes contain skin oils – cholesterol and “squalene” – which are major components of household dust. Recent research shows that dust, though often a nuisance and the source of allergies and respiratory problems, may actually be beneficial at reducing indoor air pollution.

It sounds contradictory, but it’s true. Squalene actually reduces ozone levels from 2 to 15 percent.

So… to dust, or not to dust? That is the question. Previous research shows the mere presence of humans in a room can reduce ozone levels. Ozone is a major component of smog, and exposure to it may increase one’s risk of lung irritation, asthma, heart attacks and death. The removal of ozone from indoor spaces seems to be a good thing. However, other studies show that the reaction between skin flakes and squalene produces byproducts which are known to be lung irritants and may be just as or even more harmful to your health.

Until more research is done, we are going to recommend dusting and using an air purifier to remove dust and other allergens from your indoor spaces. Just make sure the air purifier does not emit ozone.

From dust we came, and to dust we shall return…


Can Air Filters Affect Filtration Soiling?

Carpet Filtration Soiling

What is filtration soiling and what does an air filter have to do with it? Filtration soiling is soot-like discoloration that appears primarily along the edge of your carpet. Some carpet professionals also refer to this type of staining as aromatherapy candle soot, draught marking, fogging or dust marks. It is more noticeable on lighter colored carpeting than darker shades, but the quality of your carpet has nothing to do with it.

Filtration soiling can occur more commonly under closed interior doors, baseboards, along the edge of carpeted stairs or near ventilation, central heating or HVAC systems. These areas are typical of airflow that is concentrated and directed through or over the carpet’s pile. Airflow is caused by wind blowing through frequently opened windows, seeping under walls, through ventilation ducts and between rooms. Check for drafts or gaps that will force air flowing under doors or over carpeting to prevent filtration soil from accumulating in another unsuspecting area. Some of the indoor airborne pollutants contributing to this noticeable dirtiness on your floor covering include burning candles, cigarette smoke, fireplace smoke, cooking or cleaning chemical emissions.

Besides vacuuming your carpet frequently, regularly change your air filters and clean air ducts to help reduce this problem. The level of accumulated filtration soil depends on the interior airflow volume, as well as your air quality. Installing and replacing high efficiency particulate air filters (HEPA) will significantly reduce these airborne microscopic particles.

Removing filtration soil is very labor intensive. Some people feel that having scotch-guard applied over their carpet is the prescription needed to keep filtration soil from occurring, however it is only a temporary deterrent. First, you want to eliminate the cause of your indoor airborne pollutants. Next, it will be wise to have your carpet professionally cleaned, then change your air filters on a regular basis to improve indoor air quality and help reduce airborne contaminants that collect on your carpet like a magnet. Regular cleaning coupled with frequent vacuuming will also help to alleviate this unsightly discoloration.