From Master Resource

By Robert Bradley Jr.

A tweet from the Institute for Energy Research (IER) shared the latest from the U.S. Environmental Protection Agency, with the comment:

From 1970 to 2023, U.S. emissions of six criteria air pollutants declined 78% while GDP grew 321% and energy consumption rose 42%—consistent with the Environmental Kuznets Curve and driven by wealth creation and market incentives rather than central planning.

This progress can be traced back to 1970:

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[1] The 1970 Clean Air Act required the U.S. Environmental Protection Agency (EPA) to establish National Ambient Air Quality Standards (NAAQS) for common pollutants, known as criteria pollutants, to protect public health. The original list of six, finalized by 1971, are Carbon Monoxide; Lead; Nitrogen Dioxide; Ozone; Particulate Matter; Sulfur Dioxide.

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U.S. air quality has improved dramatically over the past 50+ years, even as the economy, population, vehicle miles traveled, and energy consumption (largely from fossil fuels) grew substantially.

This progress reflects “fossil fuel environmentalism” in action: technological innovations in fossil fuel extraction, refining, combustion efficiency, emissions controls (e.g., catalytic converters, scrubbers, low-sulfur fuels), and shifts within the fossil fuel mix (e.g., more natural gas, less coal in power generation) have decoupled economic growth from pollution. The Clean Air Act and industry advancements drove much of this without halting fossil fuel-based energy growth.

EPA Air Quality Concentration Trends

EPA tracks six “criteria” air pollutants. National average concentrations have fallen sharply:

Percent change in national average concentrations (from EPA data through 2024):

Pollutant	1980 vs 2024	1990 vs 2024	2000 vs 2024	2010 vs 2024
Carbon Monoxide (CO)	-87%	-80%	-67%	-25%
Lead (Pb)	—	—	—	-86%
Nitrogen Dioxide (annual)	-69%	-63%	-54%	-31%
Nitrogen Dioxide (1-hr)	-66%	-55%	-40%	-23%
Ozone (8-hour)	-29%	-24%	-18%	-7%
PM₁₀ (24-hour)	—	-36%	-39%	-7%
PM₂.₅ (annual)	—	—	-46%	-27%
PM₂.₅ (24-hour)	—	—	-45%	-21%
Sulfur Dioxide (1-hr)	-95%	-93%	-87%	-79%

These improvements stem from real-world monitoring data.

Emissions Trends (Direct Reductions)

Emissions of the six principal pollutants and precursors dropped even as society grew:

Combined emissions of six key pollutants: Down ~79% from 1970 to 2024.

Specific emissions changes (1980–2024): CO -77%, Lead -99%, NOx -75%, VOCs -61%, Direct PM₁₀ -63%, SO₂ -94%.

Economic context (1970–2024): GDP +338%, vehicle miles traveled +195%, energy consumption +43%, population +66% — while aggregate criteria pollutant emissions fell 79%. CO₂ emissions (a greenhouse gas, not a criteria pollutant) rose overall but have stabilized/declined in recent periods relative to growth.

For the latest interactive data, see EPA’s Our Nation’s Air report and Air Trends summaries.