One-inch equals 2.54 centimeters (cm) so 1 cm equals about 0.39 of an inch, and divide the cm by 10,000 in addition to the result is 1 micron. Dividing the micron by 1,000 yields the unit of distance known as a nanometer (nm). Divide 1 nm by 3 in addition to you have the approximate width of an oxygen molecule (O2), however in the air, the closest neighboring O2 molecule is about 4 nm away or the equivalent of about 25 feet for a human with a more than one-foot width. Thus, O2 maintains ample space between molecules for familiar social distancing at the atomic level, however o2 is just 20% of all the gases that occupy the atmosphere leaving plenty of room for nitrogen, the most prevalent component of air at 72%. The rest is carbon dioxide, water vapor, in addition to other trace elements like argon in addition to neon. At higher altitudes, gases like ozone, helium, in addition to hydrogen are found. When air enters our homes in addition to passes through a central Heating in addition to A/C system, the component gases are unchanged. The 1 exception is water vapor that condenses into liquid water as the air is cooled, then every one of us all adore the cooled air at lower humidity, however the tplot “conditioning” aspect of the Heating in addition to A/C system is the removal of all the other stuff that is floating around in the air. This includes polluting chemicals, pollen, dust, pet dander, mold spores, in addition to even airborne viruses that get lifted into the atmosphere, then removing these substances is left to the humble filter that is so often ignored however is the most pressing component in cleaning the air so both of us can breathe in in addition to extract the life-giving O2. This is why Heating in addition to A/C professionals are always reminding homeowners to change their filters correctly in between correctly tied up repair calls.