RESUMO
To quantify risk of ambient exposure to airborne particulates around industrial silica sand operations, this study used EPA-certified federal reference method monitors to measure the levels of PM10 and PM2.5 particulate matter. The monitoring sites were chosen based upon EPA siting criteria, dichotomous samplers were calibrated before and after sampling, and pre- and post-weight filter weights were recorded. PM2.5 levels were significantly higher (paired t-tests) at both sites - averages of 7.70 ± 6.15 and 22.7 ± 31.714;µg/m3 - than concurrent background levels of 5.11 and 6.57µg/m3 respectively; and 98th percentile values were 24.9 and 111 µg/m3, respectively. Average PM10 levels were 24.2 and 49.0 µg/m3, and second-highest annual levels were 45.5 and 69.1 µg/m3 (two years) and 62.9 ug/m3 (2015) and 61.5 ug/m3 (2016), respectively for the two sites. Neither precipitation nor wind speed or direction appeared to affect PM2.5 or PM10 concentrations.
