When using particle counters, one needs to be aware of certain terms or phrases that are commonly used when describing functions of the instrument, or how the data is viewed and reported. Data are displayed in either Cumulative or Differential mode. When viewing the data in Cumulative mode, the number (counts) associated with each channel size is the number of particles that the instrument counted for that size and greater.

Poor indoor air quality in our educational facilities is an ongoing concern in many communities. Mold in particular, has teachers, students, parents, and administrators across the country looking very closely at possible causes of contamination, and the associated costs of dealing with these problems. A growing number of professionals conducting IAQ investigations are utilizing a wide variety of testing instrumentation, including aerosol particle counters, to aid in better defining these contamination sources. I recently spent time assisting with an IAQ investigation at a middle school (Grades 6-8) in Southern Oregon, and will share the testing methodology and results in this article.

A wide variety of scientific instruments are used on a regular basis to assist in our daily IAQ investigations. Moisture meters, temperature and relative humidity probes, infrared cameras, and particle counters all have a couple of things in common. First, they are invaluable assets for successful completion of our day-to-day jobs. Second, they all are finely tuned instruments that require scheduled maintenance and calibration.