What's IN Carpet Soil and Dirt?

The majority of soil in carpet is dry, insoluble, particulate matter. A Proctor and Gamble Co., analysis of carpet soiling samples representing a cross-section from throughout the United States reveals the following data on soil in carpet:

• Tracked-in, gritty particles such as silica make up approximately 55%

• Animal fiber from people, pets and fabrics comprise about 12%

• Another 12% is vegetable matter and fiber from fabrics, indoor plants, tracked in organic material, and paper products

These combine to account for 79% of the soil nestled in carpet fibers. This soil composition varies with geographic location and use. The percentages above represent dry Particulate Matter (PM) that is the primary component of household soil.


Constituents of House Dust-


cigarette ash, incinerator ash, fibers (wool, cotton, paper and silk), fingernail filings, food crumbs, glass particles, glue, graphite, animal and human hair, insect fragments, paint chips, plant parts, pollen, polymer foam particles, salt and sugar crystals, human skin scales, animal dander, soil, fungal spores, tobacco, wood shavings.


So, how do all of these PM’s get into the carpet?

Airborne soil is made up of very small dust particles, volatized oils, carbon from gas and oil heat, carbonized soil heated by electric heat, auto emissions, tobacco smoke, cooking oils released in the kitchen, spilled and crushed food particles, flour, spices carbon released into the air from the use of electric appliances, human and pet skin flakes and hair, talcum powders, pollen, dust from deteriorating construction and furnishing components, off gassing from chemicals used in the manufacture of furnishings and carpet and in the manufacture of cleaning and personal products that may be aerosolized, dust which filters in from outside, lint particles from fabrics, and dust mite feces which are lighter than air, mold spores, odors released from organic spills such as pet urine, to name a few.

Air pollution from city air contains more concrete, mortar, degrading paint, and exhaust fumes (incl. diesel) and organic solvents which are degraded byproducts of air conditioning, than does rural air which contains different ingredients such as soil (farming), mold (trees, woods,) moisture (lakes, rivers), etc., and lesser amounts due to less concentrated housing, roads and buildings. However, rural exposure to pesticides and herbicides that become airborne is also greater than in a city. In N. OH, the burning of coal by the utilities as the major source of our local power greatly exacerbates the problem of carbon ash and soot in the air and, consequently, in our lungs, according to the EPA. The EPA is looking at the health care cost increases as a result of exposure to unnecessary PM below 2.5 microns.

When combined with general soil that is tracked in, these oily based complex soils are less and less effectively or efficiently removed. If we generously assume that vacuuming removes a majority of dry soil – say 70% - that would mean that for every 10 times you vacuum, 3 didn’t count. (And you still have the sticky soils left behind 100% of the time!)

Tracked in soil usually includes a high level of particulates (40%) including silica which has sharp, rough edges which stick to the carpet and cut and wear at the fiber, creating a better based for difficult to remove soils to adhere. Silica is capable of scratching steel, marble, tile and other hard surfaces. The results create wear and appearance issues that are difficult to reverse.

Soil is different in its composition and presence depending upon the factors above and other factors such as the economic viability of the homeowner. A lower income home may mean blue collar workers exposed to different contaminants than a white collar worker or a retired homeowner.

Daily or twice weekly maid service will result in fewer soils in the carpet where a monthly vacuuming will greatly increase soils and stains that are present and also add to the difficulty of removal as soils and stains set and become more difficult with time.

Regional differences also affect soil composition. From sandy geographic locations to clay to rocky soil…air quality…many factors make determining local composition of soil impractical and unnecessary.

PH or acidity/alkalinity of soil and sticky Particulate Matter has an enormous impact as an accelerant of damage.

IMPORTANT NOTE: We must differentiate between PM/sticky soils and airborne gaseous pollutants that are NOT removed by cleaning. The off-gassing of chemicals, construction components, natural gas, radon, and other non-PM airborne pollutants in a home environment are only subject to cleaning when – and if – they convert into the PM/sticky soils that CAN be removed by cleaning - and only after they physically land on furnishings and carpet.

The fact is that all the carpet manufacturers and even industry testing labs add 15% percent oil or clay substances to the testing soils they make to represent normal soil. Did you ever try to vacuum oil away?

Did you know that almost EVERY manufacturers’ carpet care guide says that 5%-15% of carpet soil is oily and can not be removed be vacuuming and must be removed by wet cleaning?

In addition, the inherent repellency and factory applied protectors on carpet will be covered by the sticky substances that don’t vacuum up and soil will start to accelerate. And the carpet mill will void warranties if carpet isn’t maintained properly. Go to the major carpet maker’s web sites and see how they recommend hot water extraction over any other method.

Even if you clean your furniture often with vacuuming, if you don’t wet extract your furniture at least as often as the carpet, the sticky soils that don’t remove with vacuuming will do a LOT more damage to the dyes and natural fibers used in furniture compared to the synthetic fibers and durable dyes used in most carpet. Soil on fabric contains a higher percentage of human skin fragments, dust mites (their feces is the problem) and other organic materials and will be a breeding ground for bacteria and odors (your soil test will show you that).

Look for more dust mite information at Ohio State University "FACT SHEET - MOLDS and DUST" http://ohioline.osu.edu/cd-fact/0191.html There is no fast, non-destructive and reproducible method available to definitively analyze soil that is cost effective on a case to case basis that is available to consumers. Soil is always present, but to prove it cost effectively and quickly enough to be immediately beneficial with dramatic and visual proof is not so simple. A simple test that one local cleaning company uses would assist us all to better assess the need for professional wet extraction.