A Guide to Understanding Air Cleaning Terms.


CFM (Cubic Feet per Minute) a measurement of air flow.


Although there is no universally accepted method for comparing air-cleaning devices, several investigators of portable air-cleaning units have expressed their results as a “Clean Air Delivery Rate” or CADR. The CADR is the product of the unit efficiency and the airflow rate, and is a measure of the number of CFM of air it cleans of a specific material.


Revolutions Per Minute (RPM) is a measure of speed for any rotating device. Typically found in specifications for motors.


The DOP Military Standard is the standard set by the federal government to rate particle reduction by HEPA filters. This test rates high-efficiency filters by the percentage of 0.3 micron size particles of dioctylphthalate (DOP) smoke they remove.


HEPA stands for High Efficiency Particulate Air, and like the name says, these filters are designed to remove 99.97% of all airborne pollutants 0.3 microns or larger from the air that passes through the filter (these include tobacco smoke, household dust and pollen).


Pounds per Square Foot (PSF). A measurement of air pressure


Carbon, the sixth most abundant element in the universe, has been known since ancient times. Many natural substances of base materials are used to make carbon. The most common of these are wood, coal, lignite, and coconut shell.

Amorphous carbon is formed when a material containing carbon is burned without enough oxygen for it to burn completely.


Activated carbon is the generic term used to describe a family of carbonaceous adsorbents with a highly crystalline form and extensively developed internal pore structure. Activation creates a fast internal pore network and imparts certain surface chemistries (functional groups) inside each particle. Thus activation gives carbon its unique filtering characteristics.


Zeolite is a mineral with a unique interconnecting lattice structure. This lattice structure is arranged to form a honeycomb framework of consistent diameter interconnecting channels and pores. Negatively charged alumina and neutrally charged silica tetrahedral building blocks are stacked to produce the open three-dimensional honeycomb framework. Zeolites actually attract odors & gases and trap them in its crystalline structure.


A pre filter is the primary layer of filtration that collects large particles before they reach the HEPA filter. Eliminating these larger particles, dust and hair extends the life of your HEPA filter. Occasional vacuuming of the exterior of the unit will help extend life of the filters and will also prolong the HEPA filter life.


When a gas or vapor is brought into contact with a solid, the solid takes up part of it. The molecules that disappear from the gas either enter the inside of the solid, or remain on the outside attached to the surface. The former phenomenon is termed absorption (or dissolution) and the latter adsorption.


Trap is the process of gasses and particulate matter attaching to the surface of the carbon and or zeolite structures.


There are many simple electronic devices that claim to clean the air in your home by making negative ions and ozone. The claim is accurate–they do make both ozone and negative ions, and they do clean the air in your home. However, that’s not the whole story. Also ozone gives off the “fresh” smell that occurs after a thunderstorm (a potent producer of ozone)


Ozone is produced indirectly by ion generators.


A micron is a unit of length equal to 1 millionth of a meter or .000039th (39 millionth) of an inch. Another name for micron is micrometer.


Particulate Matter Up to 10 Microns in Diameter (PM10)
The number 10 refers to the particle size measured in microns.
PM 10’s are widely considered the most dangerous to human health.


3-Speed refers to a variable speed selection control on your air cleaner. This control allows you to operate your air cleaner on low, medium or high settings depending upon your needs.


The blower wheel is a squirrel cage type wheel whose purpose is to move the air through the room. A blower wheel is more efficient than a fan as it will move more air and resists clogging.


A standard developed for measuring particulate matter in a pre defined area.


The Association of Home Appliance Manufacturers (AHAM) is an organization that represents the manufacturers of home appliances and creates standards with large manufacturers. While it has an admirable mission, it is important to note that AHAM is not a HEPA standard and seems to have been developed to resemble the output of electrostatic precipitators, a technologically inferior air cleaning method. It is for that reason that the output ratings are only valid for the first 72 hours (3 days) of operation.


The electrostatic stage filters the air using static electricity by having a static charge on the filter to allow airborne particles to “stick” to the filter, just like static-charged clothing sticks together.


Ion generators act by charging the particles in a room so that they are attracted the unit. Ion generators remove small particles (e.g., tobacco smoke) from the indoor air. These devices provide a benefit by rectifying a hypothesized ion imbalance.


A warranty is legal concept or doctrine that holds manufacturers or sellers responsible, or liable, for harm caused by defective products sold in the marketplace.


A limited warranty is a warranty that imposes certain limitations, and is therefore not a full warranty.


The main filter cartridge in Nutri-Tech air purifiers is backed by the 1 year pro-rated warranty. Under this pro-rated warranty the user of a Nutri-Tech Air cleaner becomes eligible to receive a new filter cartridge at a partial cost if the unit fails within the duration period of the pro-rated warranty period. This warranty applies to the Nutri-Tech units used under normal residential conditions only. Under the pro rated warranty the sooner you have to replace the filter, the less money you pay.


A guarantee is an assurance for the fulfillment of a conditions put forth by the manufacturer.


Is the American Society of Heating, Refrigerating and Air-Conditioning Engineers. ASHRAE publishes Standards for Ventilation for Acceptable Indoor Air Quality.


Molds produce tiny spores to reproduce, just as plants produce seeds. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. There are molds that can grow on wood, paper, carpet, and foods. When excessive moisture or water accumulates indoors, mold growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed. Molds can trigger asthma episodes in individuals with an allergic reaction to mold.


The term “sick building syndrome” (SBS) is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. The complaints may be localized in a particular room or zone, or may be widespread throughout the building.

The following have been cited causes of or contributing factors to sick building syndrome:
Inadequate ventilation: Inadequate ventilation, which may occur if heating, ventilating, and air conditioning (HVAC) systems do not effectively distribute air to people in the building.

Chemical contaminants from indoor sources: Most indoor air pollution comes from sources inside the building. For example, adhesives, carpeting, upholstery, manufactured wood products, copy machines, pesticides, and cleaning agents may emit volatile organic compounds (VOCs), including formaldehyde. Environmental tobacco smoke contributes high levels of VOCs, other toxic compounds, and respirable particulate matter. Research shows that some VOCs can cause chronic and acute health effects at high concentrations, and some are known carcinogens. Low to moderate levels of multiple VOCs may also produce acute reactions. Combustion products such as carbon monoxide, nitrogen dioxide, as well as respirable particles, can come from unvented kerosene and gas space heaters, wood stoves, fireplaces and gas stoves.

Chemical contaminants from outdoor sources: The outdoor air that enters a building can be a source of indoor air pollution. For example, pollutants from motor vehicle exhausts; plumbing vents, and building exhausts (e.g., bathrooms and kitchens) can enter the building through poorly located air intake vents, windows, and other openings. In addition, combustion products can enter a building from a nearby garage.


Particle Count per Cubic Foot is a unit of measure to classify the amount of a particular size of particles in a cubic foot of air.


An air cleaner must constantly recirculate indoor air in order to effectively reduce concentrations of airborne particulate contamination. Cleaning the total volume of air contained within a room is the equivalent of completely changing the air in that room. Air cleaner filtration capacity is expressed as the number of air changes per hour (ACH). For air cleaners of equivalent filter effectiveness, a higher ACH rating yields higher levels of air quality improvement.


Room air cleaners help with allergies by helping people live in cleaner, healthier environments. By sleeping in a room with an air cleaner, you will breathe much cleaner air all night long. And by also having an air cleaner in your office, or any other room where you spend a lot of time, you will maximize your clean air intake and minimize the allergens you breathe. Even if you have a good filter on your central air conditioning system, a room air cleaner will increase the purity of the air you breathe.


Many room air cleaners can go with you. If your den and your bedroom are similar sizes, you can move your air cleaner to the room you’re in.