Particles
Particles in Our Air
Particulate matter is a generic term for
particles suspended in the air, typically as a mixture of
both solid particles and liquid droplets. The characteristics,
sources, and potential health effects of particulate matter
depend on its source, the season, and atmospheric conditions.
Minute, invisible particles in the air in our homes and businesses are a primary threat to
health. They evade the body's filtering mechanisms and penetrate
deep into lung tissue, carrying toxic substances, which are
absorbed in the body.
This category includes copier toner, mold, fine powders
and dust, bacteria, and viruses.
Particle Sizes
The size of particles affects their potential
to cause health problems. Particulate matter is measured in microns—one micron is one
millionth of a meter; there are 25,400 microns in one inch.
Particles larger than 10 microns do not usually reach the lungs, but can irritate the eyes,
nose, and throat. Small particles with diameters smaller than 5 microns can travel deep into our breathing
passages. Particles the size of 2.5 ('PM2.5' measured by air quality monitoring agencies) and smaller is
considered 'fine particulate' and is of serious health concern. Smaller than 1 micron in size can be inhaled
right into the aveoli, or air exchange sacs at the end of our bronchial tubes in our lungs.
Examples of approximate ranges of particle diameter sizes:
- • pet dander is 5 to 10 microns (PM5 to PM10)
- • pollen is 10 microns or more
- • room dust is 10 to 300 microns
- • human hair is about 100 microns (range of 60 to 300)
- • mold spores are 10 to 30 microns
- • lead dust is 2 microns
- • anthrax is 1 to 5 microns
- • paint pigments are 0.1 to 5 microns
- • wood smoke particles are 0.2 to 3 microns
- • tobacco smoke particles are 0.01 to 4 microns
- • humidifier particles are 0.9 to 3 microns
- • copier toner is 0.5 to 15 microns
- • some bacteria are 0.3 to 10 microns
- • pesticides and herbicides are 0.001 microns
Dust
Dust in a home is inevitable. It enters via our shoes, our clothes, our pets, and
outside air pollution coming through the windows.
Not only is dust unattractive and a constant challenge
to our housekeeping, it is a carrier for harmful inhalable
substances as well. Children are at a greater risk because
they are usually quite active, and they are smaller and closer to furniture and the floor
where dust collects. Their respiratory systems are not fully developed and they take in more
air per body weight than adults. Inhalable substances carried by dust can be toxic such
as hazardous airborne chemicals or microbes; or non-toxic
such as flour or pollen. In either
case, serious health problems can occur.
Dust can be organic in nature and in this case can contain
dust mites, whose feces can cause an allergic reaction. Dust mites are also included
in our 'hybrid' category of pollutants.
Pollen
Pollen can cause seasonal allergies. On a warm, windy day,
these allergens easily enter homes via open doors and windows,
as well as on people and pets.
A primary example and source
of discomfort for many people is weeds. And of the weeds,
ragweed is the most predominant allergen, since its pollen
produces severe and widespread allergies.
Ragweed is a genus of flowering plant from the sunflower family. It blooms
in the northern hemisphere from early July to mid August or
until cooler weather arrives. Ragweed prefers dry, sunny
grassy plains, sandy soils; it likes to grow along river
banks, roadsides, in disturbed soils and vacant lots. There
are approximately 41 species of ragweed worldwide.
Ragweed is wind-pollinated; that is, pollen from ragweed gets carried
by wind and by clinging to the fur and feathers of animals
and birds passing by. For the effects of ragweed and other
pollen, see our Allergies and Asthma page.
Goldenrod is insect pollinated. Since its pollen is heavy and sticky,
it cannot become airborne. Although goldenrod blooms about
the same time as ragweed and is frequently blamed for hay
fever, it is probably not the culprit we have thought it
to be.
An interesting note—when two seemingly
unrelated plants contain similar proteins, they can cause
similar allergic reactions. For example, birch trees and
potatoes. So if you are allergic to birch tree pollen, you
may find yourself sneezing when you peel potatoes!
Pet Dander and Pet Hair
We love our pets!
We also know that the tiny flakes of skin they shed,
and the hair they leave behind on the floor and furniture
can cause or exacerbate allergies, all the way from minor sniffles to severe asthma.
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