Particle Size Distributions for an Office Aerosol

Abstract

As attention has focused on indoor air quality, it has become important to obtain basic information on the effects of heating, ventilating, and air-conditioning system operating parameters on office aerosols. In addition, it is important to know the particle size distributions (PSDs) in a typical office environment in order to address mitigation strategies. Therefore, this study was undertaken to evaluate the effect of percent outdoor air supplied and occupation level on the PSDs and mass concentrations for a typical office building. The outdoor, return, and supply air streams, as well as hallway air, were sampled using measuring equipment covering particle diameters from below 0.1 to above 3.5 pm. The mass concentrations, when the building was occupied, increased by a factor of approximately 2 when return air was recycled over ventilating with maximum outdoor air. The concentrations when unoccupied were at least as low using minimum outdoor air as those when occupied using maximum outdoor air. As expected, the outdoor air was cleaner than the other streams. The next lowest concentrations were obtained for supply air, then return air, with hallway air showing the highest concentrations. The normalized number distributions were found to have a single mode consistently near 0.13 pm; the volumetric distributions show a peak at 0.3 pm. The influence of the damper setting and occupancy level shows up only in the magnitude of the peaks. The distributions found in the hall and for the air streams showed the same general shapes, but the differences in instrumentation preclude other conclusions.

The Effect of Filtration in Heating, Ventilation, and Air‐Conditioning Systems

“…Indoor particulate contaminants are a composite of ambient aerosol infiltrated from outside and indoor sources, as reported by Owen et al (1990 and Wallace (1996). Ambient outdoor aerosol usually has a bimodal size distribution with one mode at about 0.5 µm and another at about 10 µm, with the saddle point between the peaks from 1 to 2.5 µm.…”

Characteristics of Submicron-sized Aerosol Filtration and Pressure Drop of an Electret Filter Installed in an Air Diffuser in a Residential Apartment Unit

“…For a KCl aqueous solution of 10%, the total concentration of the KCl aerosol particles was about 2 × 10 4 particles per cubic centimeter and the geometric mean diameter was 0.1 μm. The KCl solution provided particle distributions that are somewhat reflective of indoor environments (Owen and Ensor, 1990;Hussein et al, 2006).…”

Μελέτη Της Προσωπικής Έκθεσης Από Αιωρούμενα Σωματίδια, Των Φυσικοχημικών Χαρακτηριστικών Τους Και Των Πηγών Τους Σε Εσωτερικούς Χώρους Κατοικιών

“…Σε προηγούµενες µελέτες, έλαβαν χώρα µετρήσεις σε διάφορα κτίρια όπως σε γραφείo (Koponen et al, 2001;Luoma, 2001;Owen et al, 1990), σε ξενοδοχείo (Cyrys et al, 2004;Chen et. al., 2008), σε σχολείο , σε µικρό αριθµό κατοικιών (Abt et al, 2000;Morawska et al, 2001;Lazaridis et.…”