Date Published: April 3, 2017
Publisher: Public Library of Science
Author(s): Meleah D. Boyle, Sutyajeet Soneja, Lesliam Quirós-Alcalá, Laura Dalemarre, Amy R. Sapkota, Thurka Sangaramoorthy, Sacoby Wilson, Donald Milton, Amir Sapkota, Jane Hoppin.
U.S. natural gas production increased 40% from 2000 to 2015. This growth is largely related to technological advances in horizontal drilling and high-volume hydraulic fracturing. Environmental exposures upon impacted communities are a significant public health concern. Noise associated with natural gas compressor stations has been identified as a major concern for nearby residents, though limited studies exist.
We conducted a pilot study to characterize noise levels in 11 homes located in Doddridge County, West Virginia, and determined whether these levels differed based on time of day, indoors vs. outdoors, and proximity of homes to natural gas compressor stations. We also compared noise levels at increasing distances from compressor stations to available noise guidelines, and evaluated low frequency noise presence.
We collected indoor and outdoor 24-hour measurements (Leq, 24hr) in eight homes located within 750 meters (m) of the nearest compressor station and three control homes located >1000m. We then evaluated how A-weighted decibel (dBA) exposure levels differed based on factors outlined above.
The geometric mean (GM) for 24-hour outdoor noise levels at homes located <300m (Leq,24hr: 60.3 dBA; geometric standard deviation (GSD): 1.0) from the nearest compressor station was nearly 9 dBA higher than control homes (Leq,24hr: 51.6 dBA; GSD: 1.1). GM for 24 hour indoor noise for homes <300m (Leq,24hr: 53.4 dBA; GSD: 1.2) from the nearest compressor station was 11.2 dBA higher than control homes (Leq,24hr: 42.2 dBA; GSD: 1.1). Indoor average daytime noise for homes <300m of the nearest compressor stations were 13.1 dBA higher than control homes, while indoor nighttime readings were 9.4 dBA higher. Findings indicate that living near a natural gas compressor station could potentially result in high environmental noise exposures. Larger studies are needed to confirm these findings and evaluate potential health impacts and protection measures.
In recent decades, there has been a sharp increase in unconventional natural gas development across the United States. From 2000 to 2015, natural gas production increased 40%, from 19.2 quadrillion British Thermal Units (BTU) to 27.0 quadrillion BTUs, and is expected to continue to increase to 33.1 BTUs by 2040 [1,2]. Much of this growth is related to technological advances in horizontal drilling and high-volume hydraulic fracturing that have allowed access to shale gas deposits. Production from shale gas deposits increased 2,588% from 2000 to 2013 and this trend is expected to continue . A number of emerging studies have highlighted public health concerns regarding exposures to chemical, physical, and psychosocial hazards from unconventional natural gas development and production (UNGDP) and its impact on nearby communities [3–5].
Noise monitoring was conducted around two natural gas compressor stations near a UNDGP site in Doddridge County, West Virginia between April 11th to 17th, 2014, using 3M Quest SoundPro SE/DL series (3M Personal Safety Division, St. Paul, MN) sound level meters (SLMs), hereafter referred to as noise monitors. These noise monitors were used to assess area noise exposure levels. Compressor stations and participants were identified with the help of a local community group and were selected based on convenience. All monitors were set to collect slow response, A-weighted sound levels (dBA) (i.e., Leq, equivalent or average sound level during a given period; Lmin, minimum sound level during the measurement period; Lmax, maximum sound level during the measurement period; Lpeak, peak sound level; L5, noise level exceeded 5% of the time; and L95, the level exceeded for 95% of the time and representing the background level), as well as C-weighted decibel (dBC) sound levels (i.e., Leq, Lmin, Lmax, and Lpeak). Sound level meters were set to the A-weighting scale to filter out much of the low-frequency noise (i.e., considered the “normal” limit of human hearing). The C-weighted scale was used to identify impulse noise, defined as “noise consisting of single bursts with a duration of less than one second with peak levels 15 decibels higher than background noise” in 1-minute intervals to estimate exposure to low frequency noise as detailed below . Monitors were factory calibrated prior to use and then pre-calibrated using a Quest QC-10/QC-20 Calibrator (Quest Technologies, Oconomowoc, WI) onsite prior to each measurement. Following each measurement, the monitor was post-calibrated and the data were downloaded using QuestSuite Professional II (Quest Technologies, St. Paul, MN). To protect outdoor monitors, we encased each monitor in an environmental protection kit (3M SoundPro Outdoor Measuring System (SP-OMS), Quest Technologies, Oconomowoc, WI). The University of Maryland, College Park’s Institutional Review Board approved all study protocols. We obtained written informed consent from all study participants prior to any data collection and copies of the consent forms were provided to participants and also retained by the research team.
In total, 29,612 one-minute measurements were collected from 11 homes on 22 total sites (11 indoors and 11 outdoors). Six of the homes were trailer homes and five were single-family homes. Environmental noise levels associated with compressor stations were dependent on proximity of residences to the nearest compressor station, sampling location within homes (indoors vs. outdoors), and time of day (daytime vs. nighttime) as outlined below. Additional summary statistics (e.g., L5, Lmin, Lmax, Lpeak) by location within the home and distance category are provided as part of the Supplemental Material (S1 Table).
Noise exposure in communities near natural gas compressor stations is a public health concern that has not been adequately addressed. In this pilot study, we found that homes located in close proximity (<300 m) to a compressor station have higher average noise levels, both indoors and outdoors, compared to homes located further away. Residents in these homes could thus potentially be exposed to higher noise levels compared to individuals living in homes located further away. We also found that when examining noise levels for indoors vs. outdoors, a smaller difference existed for homes <300 m relative to the control homes. Additionally, we observed that, in general, daytime noise levels were higher than those observed during the nighttime, and that residents in homes located <300 m from the nearest compressor station may be exposed to low frequency noise. Findings presented herein are from compressor stations in-use and are not related to development activities. As such, they represent chronic noise exposure that community members could potentially experience for years, not transient exposures that cease after the completion of well construction. This pilot study indicates that residents living near a compressor station are potentially exposed to noise levels that are higher than the recommended U.S. EPA levels of 55 dBA (outdoor/daytime) and 45 dBA (indoor/night time). While our results suggest that the currently proposed setback distance by the State of Maryland may not be protective enough, our sample size was small and more research is warranted to determine the exact distance at which future compressor stations should be located to minimize the potential health impacts to nearby residents. States with current UNGDP activities should also consider taking a proactive approach by creating noise and health outcomes surveillance programs to monitor noise levels, as well as the health of residents living in close proximity to natural gas activity. Source: http://doi.org/10.1371/journal.pone.0174310