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

The objectives of this study were to characterize rural populations' indoor and outdoor exposure to particulate matter (PM)(10), PM(2.5), 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 (GM) indoor PM(10) (21.2 µg/m(3)) and PM(2.5) (12.2 µg/m(3)) concentrations tended to be larger than outdoor PM(10) (19.6 µg/m(3)) and PM(2.5) (8.2 µg/m(3)) concentrations (PM(10) P=0.086; PM(2.5) 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 with measurements from previous urban studies, indoor and outdoor concentrations of PM(10) and PM(2.5) in the study area tended to be smaller, whereas 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 PM(10) 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.

Noise exposures of rural adolescents.

PURPOSE: This project was conducted to characterize the noise exposure of adolescents living in rural and agricultural environments. METHODS: From May to October, 25 adolescents ages 13 through 17, living either on a farm or a rural nonfarm, were enrolled in the study. Subjects received training on the correct operation and use of personal noise dosimeters and the proper way to record their daily tasks on activity cards. Subjects completed 4 days of self-monitoring noise dosimetry, 2 days in the first round (May-July) and 2 days in the second round (August-October). In addition to dosimetry, subjects completed activity logs of their daily tasks. RESULTS: The mean daily noise exposures of adolescents living on farms and in nonfarm rural homes were between 55.4 dBA (A-weighted decibels) and 103.5 dBA, with 44% of the daily measurements greater than the National Institute of Occupational Safety and Health Recommended Exposure Level of 85 dBA. Task-based analysis of noise exposures found that activities involving mechanized equipment resulted in the highest exposures, while activities in the home resulted in the lowest exposure. No particular demographic group had a statistically higher noise exposure; therefore, specific factors apart from activities and noise sources could not be identified as risk factors for exposure to hazardous noise levels. CONCLUSIONS: The results of this project indicate that rural adolescents complete a variety of activities and are exposed to noise sources with a broad range of decibel levels. While the exposures may change from day to day, there are occasions when exposure to noise exceeds the recommended levels.