For more than 1 year, indoor and outdoor O3, NO, N02 (NOx - NO), temperature, and relative humidity as well as the air exchange rate have been measured continuously at a commercial building in Burbank, CA. The indoor concentration of a given pollutant is a function of its outdoor level, the air exchange rate, the rate at which it is removed by indoor surfaces, and the rate at which it is produced or removed by indoor chemistry. Several examples of indoor chemistry are inferred from daily and seasonal variations in the collected data.

Submicron particles play a major role in soiling processes and contribute to corrosion, current leakage and shorts in electronic equipment. For more than a year, optical particle counters have been used to continuously measure the concentrations of submicron particles at a telecommunications facility in Southern California. Separate instruments have simultaneously sampled at four locations: the outdoor air intake, immediately upstream of the HVAC filters, immediately downstream of the HVAC filters, and inside the office.