4
AIR CLEANING SYSTEMS and INdOOR AIR QUALITY
Why should I be concerned with the air
I am breathing?
Sometimes it may be better to not know what is in the air, but since you are reading
this we’ll share what the leading health agencies are reporting.
First a little background on particulate matter. The particles that float through the
air are a combination of solid particles and liquid droplets. Particles are measured
in microns, where a micron is one millionth of a meter (10-6 meters) and is also
called a micrometer. The particles that we can see with the naked eye are those
larger than 50 microns. A human hair is approximately 100 microns in diameter. The
airborne particles that result in allergies or impact our health are much smaller and
not visible with the naked eye. Mold spores and pollen particles are from to 10
microns. At times they can be visible but this is when there is a large concentration
massed together.
Before we get to the types of particles in the air, let’s review the particulates in the
air that are 10 microns and smaller and why we need to care about them. Particles
10 microns and smaller can pass through and deposit in our respiratory system
and are referred to as respiratory particulates. The concern here is that the smaller
particles can be breathed deep into the lungs. These smallest of particles tend to
stay suspended in the air longer than very large particles such as dust so there is a
greater chance for inhalation. They can also serve as a vehicle to transport contam-
inants deep into the lung area.
Particles 5 microns and larger are trapped in the throat and nasal regions, particles
between 1 and 5 microns are trapped in the trachea (leads to the lungs) and larger
lung branches and particles less than 1 micron in size go to the alveolar area which
are the tiny air sacs in the lungs. This is where the exchange of oxygen and carbon
dioxide takes place.
The primary composition of our air is made up of Nitrogen, Oxygen, Argon and
Carbon Dioxide. All of this is obviously invisible to us. Unfortunately, the respiratory
particulates are also not visible to the naked eye. Here is a summary of the com-
mon “pollutants”:
Bacteria: 0. - 5 microns
Mold spores: – 10 microns
Pollen: 10-0 microns
Dust mites: 300 microns (feces 0 microns) – most common allergen in US
Viruses: 1 micron and smaller
