Simanaitis Says

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LET’S EXAMINE automotive emissions and fuel economy following our look at Washington, D.C., shenanigans concerning 2025’s 54.5 mpg.

Back in the 1960s, three automotive emissions were identified: HC, unburned hydrocarbons; CO, carbon monoxide; and NOx, oxides of nitrogen. All three are inherent byproducts of internal combustion. And all three have deleterious effects on human health.

Volatile organic compounds (VOCs), of which HCs are part, combine with NOx to form photochemical smog. Smog is what makes the air opaque and leaves people coughing and with red, watery eyes.

CO is an outright poison. This is the toxic gas that asphyxiates people from car exhaust or faulty home heating.

As the name suggests, three-way catalytic converters on all modern cars reduce these three pollutants by significant degrees. Indeed, the cleanest of today’s cars, SULEVs, Super Ultra Low Emissions Vehicles, reduce HC/VOCs, CO and NOx by 90 percent or more. SULEV exhaust is cleaner than some urban air.

Back in the mid-1970s when catalytic converters were introduced in the U.S., only the Swedes bought into clean air. Other Europeans claimed at the time that the U.S. was overreacting. Today, automotive three-way catalysis is universal.

However, philosophical differences between the U.S. and Europeans still exist. For a variety of reasons, fuel taxation and national petroleum resources among them, Europeans have always had higher fuel prices and, thus, favored low-consumption automobiles. By contrast, the U.S. has consistently had the least expensive gasoline anywhere I’d want to live. (Sorry, Venezuela, Kuwait, Saudi Arabia, etc.) And Americans respond with a hankering for bigger cars, pickup trucks, SUVs and Crossovers, all with higher fuel consumption.

By the way, the implications of petroleum as a finite resource is another important aspect of all this. Let’s address it at another time.

Also getting the world’s attention in the last few decades is anthropogenic CO2, carbon dioxide, and its effect on changing climate (not simply weather, mind, but long-term trends). Climate science is an on-going process (science always is), and the automobile’s combustion contributing of CO2 thus enters the picture.

A pause here to exhale. Part of this exhalation is CO2, from which we understand that this colorless, odorless gas is nowhere as deadly as its CO sibling. Indeed, CO2 is vital to life on Earth: Plants ingest it and produce oxygen; we and other aerobic organisms do the opposite.

So, is CO2 an automotive pollutant?

The government has been waffling on this since 2003. That year, the U.S. Environmental Protection Agency determined that, even if it had authority, it would decline to set greenhouse gas (GHC) standards for vehicles. In 2007 the U.S. Supreme Court ruled 5-4 in Massachusetts v. Environmental Protection Agency that GHC are indeed air pollutants that can be regulated under the Clean Air Act. On June 23, 2014, in a 7-2 decision, the court affirmed that the EPA is free to regulate CO2 in the atmosphere, as long as the source of emissions in question is a traditional polluter, like a factory or a power plant, rather than a school or shopping mall. The decision was written largely by Justice Antonin Scalia. Remember him?

As emitters, cars are closer to factories than they are to shopping malls. And hence automotive CO2 has evolved as a problem.

Why not just invent a CO2 catalytic converter for cars? Because Mother Nature says no. Industrial scrubbing or sequestering of CO2 is demanding enough; scaling it down to automotive hardware isn’t feasible.

The Europeans, more concerned about climate change than Americans are, define their goals of climate mitigation and of automotive fuel-economy in one metric: grams per kilometer of CO2. The EU GHG regulatory limit of 95 g/km for passenger cars, originally scheduled for 2020, is now set for 2021.

Because CO2 is an inherent byproduct of internal combustion, a measured output of this compound is also a precise indication of the car’s fuel consumption. In particular, there are two relationships equating CO2 g/km with mpg, depending upon whether it’s gasoline or diesel fuel. (Loosely, but conceptually not incorrect, diesel has more Cs, more carbon atoms, and thus produces more CO2.)

A World Converter of CO2 generation/fuel consumption: U.S. mpg; Japan’s preference for km/l; Euro l/100 km. Source:The International Council on Clean Transportation. Also see the icct’s “Comparison of US and EU Programs to Control Light-Duty Vehicle Emissions”.

As shown by the International Council on Clean Transportation’s table, the U.S. 2025 target of 54.5 mpg is equivalent to 100.9 g/km CO2. The European 2020 limit, since extended to 2021, of 95 g/km CO2 would require 57.9 mpg U.S. for a gasoline-fueled car and 66.5 mpg U.S. for a diesel.

The icct also notes that Euro phase-in standards are generally four years ahead of U.S. equivalents, but the U.S. has had more rigorous testing requirements, more comprehensive test methodologies and better real-world compliance enforcement. By the way, the icct was key in uncovering “VW’s Diesel Scam” in 2015.

Bringing matters up to date, I note an Automotive News article from March 9, 2017, titled “EPA Chief Says Congress Should Weigh Whether Carbon Dioxide is a Pollutant.” Scott Pruitt says he’s doing this to reduce “regulatory uncertainty” for U.S. industry.

Yet a March 20, 2017, Automotive News headline reads “EPA Hands Industry a Win, and Uncertainty.”

It ain’t over till the fat lady coughs. Or maybe she doesn’t cough. ds

© Dennis Simanaitis,, 2017


  1. jlalbrecht64
    March 22, 2017

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