88
A study that combined air quality monitoring data with emissions, and used
modeling to predict concentrations in air pollution exposure areas was undertaken
on a regional scale in the Dallas-Ft. Worth area to assess effects from the development of the Barnett Shale (Zavala-Araiza et al. 2014). The investigation measured
VOC concentrations hourly over a period of 20 months in an area of high shale gas
development density, an urban location, and under background conditions. Publicly
available VOC emission data from identified shale gas sources were used to predict
the contributions of Barnett production to regional VOC levels.
The 20-month sampling campaign captured seasonal and operational variability,
and collected data at relatively short (hourly) intervals over a large geographic area.
The placement of samplers in locations with different types of land use allowed for
background concentrations to be corrected, and the availability of an emissions
inventory from a large number of sites provided detailed information on source
types. The predictive model was parameterized with information about topography
and meteorology, providing a useful approach for characterizing human exposure
pathways. The results of the investigation indicated that VOC emissions have a low
variability over time during the production phase of the wells, and that VOC emissions from the well pads were dominated by pneumatic devices used to control
valves and other equipment. The variability in VOC concentrations was best
explained by meteorology, rather than by episodic emission events (Zavala-Araiza
et al. 2014).
The Wattenberg gas field near Denver, Colorado has been produced conventionally since 1970 (Ladd 2001). Regional air monitoring found substantial emissions
of methane, VOCs, NOx and other criteria air pollutants in the area, and the investigation has evolved into a multi-institution, longer-term study of the environmental
impacts from O&G operations along the Rocky Mountain Front Range (Pétron
et al. 2012, 2014). This investigation was funded as a Sustainability Research
Network by the National Science Foundation, and has produced more than 60 publications since 2014 (https://www.airwatergas.org/). Areas investigated include air,
water, public health, and socioeconomic-political factors.
Although substantial air impacts have been documented from all different types
of oil and gas production operations, it is not clear if air quality impacts from “fracking” are any worse or better than those from conventional O&G production. Many
of the air emissions are from surface infrastructure, like leaking seals on compressors or vents on oil stock tanks, and these are the same for both conventional and
unconventional well sites. Unconventional O&G uses hydraulic fracturing and so
does some conventional O&G development. Air quality impacts appear to be similar and are not specifically related to the use or non-use of fracking. The intensity of
the development seems to be more important than the specific method.
5 Fracking and Air Quality
A study that combined air quality monitoring data with emissions, and used
modeling to predict concentrations in air pollution exposure areas was undertaken
on a regional scale in the Dallas-Ft. Worth area to assess effects from the development of the Barnett Shale (Zavala-Araiza et al. 2014). The investigation measured
VOC concentrations hourly over a period of 20 months in an area of high shale gas
development density, an urban location, and under background conditions. Publicly
available VOC emission data from identified shale gas sources were used to predict
the contributions of Barnett production to regional VOC levels.
The 20-month sampling campaign captured seasonal and operational variability,
and collected data at relatively short (hourly) intervals over a large geographic area.
The placement of samplers in locations with different types of land use allowed for
background concentrations to be corrected, and the availability of an emissions
inventory from a large number of sites provided detailed information on source
types. The predictive model was parameterized with information about topography
and meteorology, providing a useful approach for characterizing human exposure
pathways. The results of the investigation indicated that VOC emissions have a low
variability over time during the production phase of the wells, and that VOC emissions from the well pads were dominated by pneumatic devices used to control
valves and other equipment. The variability in VOC concentrations was best
explained by meteorology, rather than by episodic emission events (Zavala-Araiza
et al. 2014).
The Wattenberg gas field near Denver, Colorado has been produced conventionally since 1970 (Ladd 2001). Regional air monitoring found substantial emissions
of methane, VOCs, NOx and other criteria air pollutants in the area, and the investigation has evolved into a multi-institution, longer-term study of the environmental
impacts from O&G operations along the Rocky Mountain Front Range (Pétron
et al. 2012, 2014). This investigation was funded as a Sustainability Research
Network by the National Science Foundation, and has produced more than 60 publications since 2014 (https://www.airwatergas.org/). Areas investigated include air,
water, public health, and socioeconomic-political factors.
Although substantial air impacts have been documented from all different types
of oil and gas production operations, it is not clear if air quality impacts from “fracking” are any worse or better than those from conventional O&G production. Many
of the air emissions are from surface infrastructure, like leaking seals on compressors or vents on oil stock tanks, and these are the same for both conventional and
unconventional well sites. Unconventional O&G uses hydraulic fracturing and so
does some conventional O&G development. Air quality impacts appear to be similar and are not specifically related to the use or non-use of fracking. The intensity of
the development seems to be more important than the specific method.
5 Fracking and Air Quality