Just in time for Halloween, the Associated Press facilitated some classic “Keep It in the Ground” fear-mongering Tuesday by publishing an op-ed penned by Texas A&M University professor Gunnar Schade that essentially claims the shale boom has damaged U.S. air quality over the past 10 years. From Dr. Schade’s op-ed:

“[A]bout 10 years ago, the picture on air pollutants in the U.S. started to change. The ‘fracking boom’ in several different parts of the nation led to a new source of hydrocarbons to the atmosphere, affecting abundances of both toxic benzene and ozone, including in areas that were not previously affected much by such air pollution…”

“[T]he shale boom has created a new source of large-scale, diffuse hydrocarbon emissions that adversely affect air toxics levels. While the effects are subtle, they happened in areas generally without any air pollutant monitoring, making estimates of trends difficult.”

Not only is the research used to support Dr. Schade’s claims of elevated emissions from oil and gas development highly questionable (we’ll address that in a moment), the op-ed completely ignores expert consensus and data showing that increased natural gas use made possible by fracking has dramatically improved overall U.S. air quality, rather than the other way around.

This egregious omission was immediately criticized by independent, third party experts such as former Pennsylvania Department of Environmental Protection Secretary John Hanger and Resources for the Future Senior Research Associate Daniel Raimi.

The most recent scientific data confirming natural gas’ contribution to improved air quality couldn’t be clearer. As natural gas consumption has increased 24 percent since the start of the shale boom, EPA data show emissions of the most dangerous “criteria pollutants” — sulfur dioxide, nitrogen dioxide and fine particulate matter (PM2.5) — have decreased dramatically.

As the following International Energy Agency graphic shows, sulfur dioxide and particulate matter emissions from natural gas are negligible, while nitrogen oxide (NOx) emissions are far lower than other traditional fuel sources.

EPA has previously noted that sulfur dioxide is of “greatest concern,” primarily because it can lead to PM2.5 formation. Fracking’s role in reducing PM2.5 pollution has even prompted University of California-Berkeley professor Richard Muller to say:

“For shale gas is a wonderful gift that has arrived just in time. It can not only reduce greenhouse gas emissions, but also reduce a deadly pollution known as PM2.5 that is currently killing over three million people each year, primarily in the developing world.”

At no point in Dr. Schade’s op-ed is it mentioned that increased natural gas use has significantly reduced dangerous “criteria pollutants” that have killed millions worldwide — which would seemingly be essential information to include in any serious op-ed discussing air pollution.

But Dr. Schade’s omission of this critical information is not all that surprising considering some of the data he uses to support his claims that localized emissions from oil and gas infrastructure are harmful to public health. Schade’s claims that oil and gas development is largely responsible for widespread increases in ground level ozone is a prime example. From the op-ed:

“[U]nconventional production has not only increased truck traffic and related emissions in shale areas, but also established a renewed source of hydrocarbons. They enter the atmosphere from leaks at valves, pipes, separators and compressors, or through exhaust vents on tanks. Together with nitrogen oxides emissions, largely from diesel engines in trucks, compressors and drilling rigs, these hydrocarbons can form significant amounts of harmful, ground-level ozone during daytime.”

Again, actual data do not support Dr. Schade’s conclusions. NOx is the primary precursor to ground level ozone formation, according to the Texas Commission on Environmental Quality. TCEQ has also noted that just five percent of north-central Texas NOx emissions are from upstream oil and gas activities, explaining that “NOx emissions are a more vital or limiting component than VOC (volatile organic compound) emissions in ozone formation.”

The latter point is essential to understand, considering oil and gas production sites are not a major source of NOx emissions and that NOx emissions from natural gas combustion are far lower than other traditional fuel sources. So not surprisingly, EPA data show that emissions of NOx has decreased 49 percent since 2005 as natural gas use has ramped up.

Bottom line: Contrary to activists’ continued claims, oil and gas production sites are not a major source of NOx emissions, and therefore are not a major contributor to ground level ozone levels. Tailpipe emissions continue to be the primary source of ground level ozone, and increased natural gas use from fracking has actually resulted in the net ozone reductions the U.S. has experienced in recent years.

On a related front, Schade also claims the fracking boom has led to a spike in benzene emissions. From the op-ed:

“Aside from effects on ozone trends, the increase of hydrocarbon emissions has also led to the resurgence of an air toxic thought to be a story of the past in the U.S.: benzene.”

But Schade admits his conclusion that dangerous benzene emissions from oil and gas sites are a widespread problem is largely based on speculation rather than hard data:

“While benzene is generally monitored below levels the Texas Commission on Environmental Quality (TCEQ) would be concerned about, it is becoming clear that levels must have increased at rural shale area locations.”

“Annual average benzene levels are now below 1.5 parts per billion at over 90 percent of locations monitoring benzene regularly, but few such monitoring stations are in or near shale areas.”

“High levels of benzene in shale areas, such as near well pads in the Barnett shale in Texas, were recorded early into the fracking boom, but few continuous air monitoring data are available to this day, with virtually no data prior to the fracking boom for comparison.”

Schade’s speculation is refuted by numerous recent studies based on actual production site measurements.

The Colorado Department of Public Health and Environment recently evaluated 10,000 air samples from parts of the state with “substantial” oil and gas operations and found:

“All four cancer-causing substances (benzene, ethylbenzene, formaldehyde and acetaldehyde) were within acceptable risk range, even for combined exposures.”

A peer-reviewed 2016 University of Texas at Arlington study based on 12,800 mobile mass spectrometry measurements across 13 Eagle Ford Shale counties found BTEX readings — including benzene — found emissions were well below federal safety standards.

And a peer-reviewed 2015 Drexel study based on measurements at Marcellus well sites states, “We did not observe elevated levels of any of the light aromatic compounds (benzene, toluene, etc.).”

All these overlooked studies considered, it probably shouldn’t surprise anyone that Schade also claims oil and gas system methane emissions are underestimated based on an infamous and thoroughly debunked 2011 Robert Howarth/Anthony Ingraffea study. Schade’s focus on this study — the textbook definition of an outlier produced by well known anti-fracking activist researchers — reveals his own bias, as numerous recent studies (including studies conducted by the Environmental Defense Fund!) that find methane leakage rates are extremely low.

The headline to Schade’s op-ed asks: “How has air quality been affected by the US fracking boom?” Contrary to Schade’s one-sided take, which seems more rooted in advocacy than science, Massachusetts Institute of Technology economics professor Michael Greenstone might have answered that question most accurately when he said:

“There’s a strong case that people in the U.S. are already leading longer lives as a consequence of the fracking revolution.”