Air Quality Research

The rise of unconventional oil and gas development across the United States’ interior west has led to public concerns about impacts on air quality. Oil and gas development can affect air quality at local, regional, and global scales. Local concerns arise when oil and gas development is placed in close proximity to where people live and work. Truck traffic and diesel powered equipment produce emissions and some oil and gas contains hazardous air pollutants such as benzene that can be detrimental to human health. Regionally, oil and gas development is contributes to the volatile organic compounds and nitrogen oxides that react together in the atmosphere to produce ground-level ozone (smog).

At the same time, using natural gas in place of coal for electricity generation can reduce nitrogen oxides emissions. Transitioning from coal to natural gas for electricity generation can also decrease emissions of the global warming pollutant CO2, but those reductions can be offset if methane, a highly potent greenhouse gas, is released during drilling and production. Researchers in the Air Water Gas air quality team are working to better understand the tradeoffs between these local, regional, and global impacts of oil and gas development.

Objectives

  • Accurate and up-to-date emission inventories are important tools to understand how best to reduce the air pollution impacts of oil and gas development. Our project is using a combination of airborne and ground-based atmospheric measurements of methane and a suite of volatile organic compounds to quantify regional-scale emissions and to document the chemical composition of regional air masses and local plumes. As regional differences in emission composition and magnitude emerge, we are investigating potential reasons for such differences.

Above: a NOAA mobile lab outfitted to collect and analyze air samples on the road.

  • Regulators in some Rocky Mountain states have moved ahead of the U.S. Environmental Protection Agency in requiring air pollution controls for oil and gas development activities, due to concerns about ozone, climate change, and other impacts. Our project is examining how regulatory requirements are evolving in four western states: Colorado, New Mexico, Utah and Wyoming.
  • Trends in availability and use of natural gas are expected to have complex ramifications for the U.S. energy system and associated emissions and air quality over coming decades. Our project is using a long-term planning model of the U.S. energy system to examine how emissions might change under alternative scenarios for energy development, and then taking these emissions projections as input for modeling of air quality and associated health and environmental impacts in the Rocky Mountain region.
  • Recent advances in low cost air quality monitoring equipment can be used to help educate citizens about the impacts of oil and gas development, as well as improving researchers’ understanding of spatial and temporal variability in levels of ozone and in methane emissions. Our project is refining low cost monitors that have the ability to measure several air pollutants, including ozone and methane, and has built about 40 of these devices. These monitors are being used to assess indoor air quality associated with different home heating fuels, including natural gas, propane, and wood. They are also being used to assess spatial and temporal variability in oil and gas production basins to improve our understanding of emissions and exposure at the local scale (< 10 km). In conjunction with the AWG health effects team, these data will contribute to estimating risks of human exposure to chemical and nonchemical stressors associated with oil and natural gas development in the Denver-Julesburg (DJ) Basin.

Findings

  • AWG researchers and air monitoring equipment have contributed to several large field studies that are allowing researchers to more accurately quantify methane and non-methane hydrocarbons emissions from oil and gas development. These studies measure emissions being released from individual sites on the ground as well as taking regional air samples by airplane.
  • AWG researchers and their collaborators have compared “top-down” samples of methane in the atmosphere with “bottom-up” estimates from production equipment inventories and found that in some basins, actual methane emissions from oil and gas development are significantly higher than expected from the bottom-up inventories. One cause of the disparity has been the inventories’ failure to reflect abnormally high-emitting facilities that cause a disproportionate amount of methane emissions compared to more typical oil and gas production facilities.
  • Improved emissions data have helped AWG researchers and their partners to determine the cause of high ozone levels in Utah’s Uinta Basin. The occurrence of high ozone levels there and in southwest Wyoming was surprising to the atmospheric science research community because it occurred in winter, whereas ozone is typically a summertime problem. Field studies have shown that winter temperature inversions in these basins can allow VOCs from the oil and gas industry to build-up and produce ozone when they combine with nitrogen oxides in chemical reactions driven by sunlight reflected from the snow.
  • AWG researchers are also working to bring low-cost technologies into the hands of communities that are experiencing oil and gas development. These tools are helping educate the public about the benefits and costs of oil and gas development and may one day allow local communities to conduct their own scientific investigations of emissions and exposure.
  • AWG researchers are not only looking at the immediate impacts to air quality from current oil and gas production. They are also studying future scenarios for oil and gas production and our U.S. energy system in order to understand implications for regional air quality and greenhouse gas emissions. More abundant natural gas can help reduce emissions from electricity generation when natural gas displaces coal. However, there is no emissions benefit if natural gas is used in place of renewable energy. Modeling done by AWG researchers suggests that in the Rocky Mountain region, wind power and natural gas are close competitors to fill future needs for low-cost electricity production, so emissions tradeoffs require careful examination.