More initial tests using the particle counter that kimwy66 linked to in another thread.
Concentrations of 0.5-2.5 micron-sized particles per cubic meter this morning were:
- Outside air: 26,475,000
- Small room using a standard Sharp on medium: 1,023,700
- Small room using a small Austin Air on high: 4,942000
- Large room using an IQAir on low: 4,236,000
My conclusions so far are:
The Sharp is good. It's running at an acceptable noise level and brings particulate concentrations down to 3% of outside air.
The Austin Air either needs a filter change or there's major air leakage past the filters.
The IQAir running at low is not anywhere near as effective as I had thought it would be. It just doesn't generate enough airflow for the size of the room.
There are some caveats or notes to this quick and dirty testing:
Inside air is supposed to be lower in particulates than outside air anyway. I haven't yet established a baseline for non-filtered, inside air.
Counting particles doesn't translate directly into any sort of air quality index number as gas pollutants are ignored by a particle counter. And PM2.5 recommendations are based on a different unit of measurement (weight instead of particle count) and a conversion is impractical.
Still, I consider these figures better than no information.