MEASUREMENT OF AIRBORNE AND FLOOR DUSTS IN A NONPROBLEM BUILDING

Part of a year-long study was to establish baseline measurements of ai rborne and surface dusts in a building. A four-story building was moni tored with a laser particle counter (IPC) to characterize airbourne pa rticle size ranges of >0.5 to >15 mu m, a fine particle sample (FPS) t o measure 24-hour total airborne dust mass concentrations, and a high- volume small surface sampler (HVS3) to assess dust levels on floor sur faces. Monthly measurements were taken on each floor for 5 months. An improved cleaning regimen was instituted, and monitoring continued for 7 months. Mean LPC indoor particle counts correlated well with those outdoors (0.92). Mean LPC size distributions were similar on all floor s, decreasing as particle size increased, and remained fairly constant over the study. FPS airborne dust mass concentrations were low throug hout the building (5 to 11.5 mu g/m(3)). In comparing FPS and LPC meas urements, mean 24-hour FPS total airborne dust mass measurements prove d the most meaningful over a long term. LPC data were proven useful fo r the preliminary site evaluations or to locate particle sources. Mean building HVS3 dust loads for the year were 2.1 +/- 1 g/m(2) for carpe t and 0.08+/-0.03 g/m(2) for vinyl tile. An inverse relationship betwe en carpet dust and airborne dun showed that (1) as carpet dust is dist urbed and resuspended, dust levels in the carpet decrease and airborne dust levels increase, and (2) as airborne dust settles onto carpet, t otal airborne dust mass decreases while carpet dust mass increases. Al l measurement methods used helped physically characterize the airborne and surface dusts and provide baseline measurements for a nonproblem building.