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Air QualityCars, Smog, and EPA

Cars, Smog, and EPA

Cars, Smog, and EPA

Over the past fifty years, EPA has overseen incredible reductions in auto pollution.

This is a component of an occasional series of posts concerning the evolution of pollution standards. Today’s subject is pollution control for brand spanking new vehicles, which have been known to cause smog because the Nineteen Sixties. The history of those pollution standards is kind of distinctive.

On the high temperatures in internal combustion engines, a few of the nitrogen within the air actually burns, leading to the formation NO or NO2, that are collectively called NOx. NOx plays a job in forming ground level ozone and final particulates (PM2.5), each of that are human health hazards.

For the primary 20 years of federal regulation, Congress set the NOx standards for brand spanking new cars itself. That’s quite different from the standards for industrial pollution sources, which Congress has all the time delegated to EPA. The rationale can have been the high political stakes within the automotive industry or the relatively easier task of setting standards for brand spanking new products in a single industry using a single energy process.

For convenience, I’m only going to handle standards for cars, although they’ve change into a smaller a part of the vehicle mix as SUVs and pickup trucks have grown in popularity. The initial standard, set within the 1970 Clean Air Act, was 3.1 grams per mile (gpm) for NOx. Achieving that standard was considered nearly unattainable when Congress created this mandate, however the mandate forced the automotive corporations to make technological breakthroughs with catalytic converters.

Note that the usual is ready by way of pollution per mile reasonably than pollution per gallon. That implies that any increase in fuel efficiency robotically helps an organization meet the pollution standards as well. Theoretically, a automotive could don’t have any pollution control in any respect but get such phenomenal mileage that it met the pollution standard. Actual mileage has improved but not enough to obviate the necessity for pollution controls.

Congress adjusted the standards twice. A 1977 amendment reset the limit to 1 gpm in 1981. The 1990 amendments modified the usual to 0.6 gpm, effective in 1994. These are called Tier 1 standards. Apparently Congress didn’t relish the duty of periodically resetting the standards itself  The 1990 Amendments authorized EPA to set standards for 2004 and beyond.

In 1998, nevertheless, the Clinton Administration brokered a deal between the automotive corporations and Northeastern states who complained that ozone was getting blown into their states from upwind states. The businesses agreed to sell national Low Emission Vehicles, with an NOx standard of 0.3pm.
The next 12 months, EPA proposed Tier 2 standards, including a  0.07 gpm NOx standard. Tier 3 standards were phased in starting with 2017 cars. When fully phased in, they are going to set a 0.7 fleetwide ceiling of 0.07 for NOx plus NMOG (non-methane organic gases).

In April of 2023, the Biden Administration proposed latest standards for cars, SUVs, and lightweight trucks that covering each greenhouse gases and standard pollutants like NOx. EPA proposed a phasedown for NOx to 12mg/m, or 0.012 gpm. These are fleetwide requirements, so the more EVs an organization sells, the less it needs to cut back emissions from its vehicles with internal combustion engines. Theoretically, if the proportion of electrical vehicles were high enough, it wouldn’t need pollution controls on its gas-powered vehicles. That’s not, nevertheless, a sensible. compliance option.

This needs to be considered a successful regulatory program. The Biden proposed standard allow lower than 1% of the pollution levels that Congress mandated in 1970.

Still, this system has an inherent limitation: it addresses pollution per mile, but not the variety of miles driven.  That has roughly tripled since 1970.  It’s not a term I’m found of, but I even have to say the present figure is jaw dropping: 3.2 trillion miles in 2022. (If we charged people $2 per mile, we could cover the entire government budget, social security and Medicaid included. How about that for tax reform?)

In consequence of the expansion in vehicle use, the improvements in vehicle pollution control haven’t resulted in proportional improvements in air quality. Smog has definitely gotten higher in urban areas, but not nearly as much because it might need, if we had more compact cities and heavier use of public transportation. Given the limited tools that Congress gave it, nevertheless, EPA has achieved impressive results.


1990 Clean Air Act Amendments, air pollution, Biden Administration, cars, Clean Air Act, NOx, smog, vehicle emission standards


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