Size-Resolved Concentrations of Particulate Matter and Bioaerosols Inside versus Outside of Homes

Abstract

Size-resolved airborne particulate matter samples (PM 2.5 , PM 10 , and TSP) collected inside ten northern California homes over four days and one night (9-12 h/sample, spanning a 3.5 week period) were analyzed for protein, endotoxin, and (1→3)-β-D-glucan concentrations. Some simultaneous size-resolved outdoor samples were also collected. The associations of residential characteristics and occupant behavior with the indoor airborne levels were investigated. In addition, the relation between these chemical biomarkers and the more traditional culturing approaches was studied. Most of the indoor mass concentration of airborne particles and protein was in the fine fraction (PM 2.5 ), while the mass of airborne endotoxin and (1→3)-β-D-glucan was mainly in the coarser fractions (PM 10-2.5 and PM TSP-10 ). No strong correlations were seen between short-term (3-6 min) culturable bacteria and fungi counts and the corresponding longer-term (9-12 h) biomarker levels. Daytime indoor levels of the biomarkers tended to be higher than outdoors, especially for the PM 10-2.5 fraction, but only in a few cases were the indoor/outdoor relationships statistically significant. Indoor pets were associated with elevated airborne PM and bioaerosols inside homes. Two other factors, wall-to-wall carpet and older houses, also appear to be associated with some elevations in indoor levels.

Quantitative filter forensics with residential HVAC filters to assess indoor concentrations

“…Only a limited number of studies have monitored the concentrations of TSP in USA homes. Chen and Hildemann monitored the airborne TSP in 10 northern California homes over 4‐day and one‐night intermittent sampling time and found a similar median but a smaller range (TSP concentrations in the range of 5.2 to 97.2 µg/m 3 with a median of 27.6 µg/m 3 ). Differences in sample size, home location, sampling period, and sampling type (central HVAC filter vs airborne sample in a room) as well as occupant density may also have contributed to the differences in PM concentrations observed.…”

Impact of dwelling characteristics on concentrations of bacteria, fungi, endotoxin and total inflammatory potential in settled dust

“…Similar to our findings, two other studies by Refs. [25,17] measured significantly higher levels of endotoxin in dwellings occupied by higher number of persons and in 10 California homes significant correlations have been found between occupancy and endotoxin exposure [14]. In another study differences in endotoxin exposures have been found when occupants were absent from their home for two weeks.…”

Free and combined amino acids in size-segregated atmospheric aerosol samples

“…Moreover they can be modified by chemical and physical processes in the atmosphere (Milne and Zika, 1993;McGregor and Anastasio, 2001;Franze et al, 2005;Haan et al, 2009). Therefore some authors only studied the total protein contribution through bicinchoninic acid assay (Micro BCA Protein Assay Kit) for the colorimetric detection and quantitation of the total proteins (Kang et al, 2012;Chen and Hildemann, 2009); or using the Nano-Orange Protein Quantification Kit (Molecular Probes, Eugene, OR) (Menetrez et al, 2007b;Menetrez et al, 2009;Mandalakis et al, 2011) or through water-soluble organic nitrogen analysis (Zhang et al, 2002). A method of determining combined amino acids in bioaerosols is the hydrolysis of peptides and proteins, followed by analysis of total amino acids (Samy et al, 2011).…”