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Air Quality Trends

Unlike atmospheric carbon dioxide levels, which continue to increase with increased fossil fuel combustion, environmental regulations and a general attitude toward environmentally sound management practices has contributed to an overall decrease in several key air pollutants.

Drew Nelson shares the Environmental Defense Fund’s perspective on the role corporations, non-profits and regulatory agencies have to play in reducing emissions and bringing a future with cleaner air for everyone.


Minimizing Methane Emissions – Drew Nelson – Environmental Defense Fund

There’s a lot of information out there about the impact that methane has on the climate system. Our analysis shows that methane is responsible for 25% of the warming that we feel today, and that the oil and gas sector is the largest industrial source of that methane emissions globally. In a world, particularly in 2016, where every month seemed to break the hottest February ever, the hottest March ever, etc., where we can find solutions to drive down emissions. It’s a pretty big opportunity for us to minimize the impacts of climate change.

Our analysis shows that globally, if you could reduce oil and gas methane emissions 45%, which is the goal that Canada, the United States and Mexico have agreed to, it would have the same short term climate impact as closing 1/3 or about 1,000 coal fired power plants. That’s a huge untapped opportunity and is why in late 2016 environment ministers from 19 different countries came together to identify oil and gas methane as the next big climate opportunity. It’s why the international energy agency has identified oil and gas methane reductions as one of five climate opportunities to drive down energy related greenhouse gas emissions, and why the international energy agency has also said that minimizing methane emissions is fundamental for the oil and gas industry in order to increase their credibility and ensure the role of natural gas in going forward.

There’s a lot of optimism that we have that this issue has grown from one that is specific to the United States, to one that’s been North American focused, to one that’s now truly global. Methane emissions are not just a problem here in the United States. They’re a problem everywhere. Oil and gas operations, pretty much, take place all across the globe. Where those operations exist, there are cost effective solutions to drive down those emissions, improve air quality, reduce waste, but also, importantly, reduce the impacts that we’re feeling today from climate change.

Carbon Monoxide

Carbon monoxide does not directly affect the global temperature in the same way as methane and carbon dioxide. However, carbon monoxide does affect the ability of the atmosphere to process and purge other gases.1NASA, March 2000, Carbon Monoxide, Earth Observatory, (accessed March 9, 2017). In the presence of sunlight, carbon monoxide can combine with other pollutants to form smog and lower-atmospheric ozone. From 1980 to 2021, the concentration of carbon monoxide in the atmosphere showed an 87% decrease.2U.S. Environmental Protection Agency (EPA), 2022, August 1, Carbon Monoxide Trends, (accessed December 23, 2022).

Nitrous Oxides

Nitrogen oxides (NOX) are a group of highly reactive gases that enter the atmosphere as emissions from fossil fuel combustion. Inhaling NOX produces respiratory irritation in humans, and long-term exposure may lead to the development of asthma. When atmospheric NOX combines with water in the atmosphere, it contributes to acid rain.3U.S. Environmental Protection Agency (EPA), 2016, Nitrogen Dioxide Trends, (accessed March 9, 2017). Over the past 800,000 years, concentrations of nitrous oxide in the atmosphere rarely exceeded 280 ppb. Levels have risen since the 1920s, however, reaching a new high of 334 ppb in 2021. This increase is primarily due to agriculture.4U.S. Environmental Protection Agency (EPA), 2022, August 1, Climate Change Indicators: Atmospheric Concentrations of Greenhouse Gases, (accessed December 23, 2022).

Sulfur Oxides

Sulfur oxides (SOX) enter the atmosphere through the combustion of fossil fuels especially in power plants and industrial settings. Fuel with high sulfur content emits higher concentrations of SOX. These gases react with other gases to produce small atmospheric particles, which contribute to particulate matter (PM) pollution. PM pollution can cause serious health problems if inhaled as the small particles can penetrate lung tissue. Similar to NO2 being used as an indicator gas for all NOX, sulfur dioxide stands in for SOX in national monitoring. From 1980 to 2021, atmospheric concentrations of SOX decreased by 94%.5U.S. Environmental Protection Agency (EPA), 2022, August 1, Sulfur Dioxide Trends, (accessed December 23, 2022).


Carbon Monoxide Video: Courtesy NASA

Images: “Hot Air Balloon Ride” by mirsasha licensed under CC BY NC ND 2.0