Indoor and outdoor particulate matter and endotoxin concentrations in an intensely agricultural county

Abstract

The objectives of this study were to characterize rural populations’ indoor and outdoor exposure to PM10, PM2.5, and endotoxin and identify factors that influence these concentrations. Samples were collected at 197 rural households over five continuous days between 2007 and 2011. Geometric mean indoor PM10 (21.2 μg m−3) and PM2.5 (12.2 μg m−3) concentrations tended to be larger than outdoor PM10 (19.6 μg m−3) and PM2.5 (8.2 μg m−3) concentrations (PM10 p= 0.086; PM2.5 p <0.001). Conversely, GM outdoor endotoxin concentrations (1.93 EU m−3) were significantly larger than indoor (0.32 EU m−3) (p<0.001). Compared to measurements from previous urban studies, indoor and outdoor concentrations of PM10 and PM2.5 in the study area tended to be smaller while, ambient endotoxin concentrations measured outside rural households were 3-10 times larger. Contrary to our initial hypothesis, seasonality did not have a significant effect on mean ambient PM10 concentrations; however, endotoxin concentrations in the autumn were almost seven-times larger than winter. Excluding home cleanliness, the majority of agricultural and housing characteristics evaluated were found to be poorly associated with indoor and outdoor particulate and endotoxin concentrations.

Airborne endotoxin concentrations in indoor and outdoor particulate matter and their predictors in an urban city

“…31,32 On the other hand, studies in agricultural regions reported that outdoor endotoxin concentrations in PM 10-2.5 were higher than indoor concentrations, suggesting sources including agricultural dust and domestic animals. 33,34 In the present study, the indoor endotoxin concentrations in PM 2.5 were significantly higher in homes with pets and in homes with tatami or carpet flooring, and lower in homes that used air purifiers, after adjusting for outdoor endotoxin concentrations. The indoor endotoxin concentrations in PM 10-2.5 were also significantly higher in the homes with tatami or carpet flooring, but did not differ in relation to there being a pet in the homes and the use of air purifiers.…”

Urban enhancement of PM10 bioaerosol tracers relative to background locations in the Midwestern United States

“…The obtained average endotoxin level in October was 6 times lower than a previously reported average autumn endotoxin level (2.63 EU m −3 ) in Keokuk County, Iowa, which is in close spatial proximity to agricultural dust sources [ Pavilonis et al ., ]. Importantly, these data show that the very high endotoxin levels that have been documented in agricultural areas of Iowa do not extend to background sites or urban areas.…”

Electrostatic dust collectors compared to inhalable samplers for measuring endotoxin concentrations in farm homes

“…In Iowa, dichotomous samplers were used to sample 197 rural homes from 2007–2011 (Pavilonis et al , 2013). This study had a range of 0.01 to 4.5 EU/m 3 comparable to our range of BS endotoxin values over both seasons (0.01 to 10.74 EU/m 3 ).…”