Fossil Fuels and Air Pollution

Module 10 (11/3–11/9) · Fossil Fuels and Air Pollution · Blueprint Pillar 3 · PGCC Outcome 4 · Download .docx

Objectives

Explain how fossil fuels form and why they are nonrenewable.
Distinguish primary from secondary air pollutants.
Explain acid rain formation and its ecological effects.
Describe the Montreal Protocol and its impact on stratospheric ozone.

Key terms

Fossil fuel: Energy source formed from ancient organic matter: coal, oil, or natural gas.
EROI: Energy Return on Investment — ratio of energy obtained from a fuel to energy needed to extract it.
Primary air pollutant: Substance emitted directly into the atmosphere in a harmful form (CO, SO₂, particulates).
Secondary air pollutant: Pollutant formed in the atmosphere through chemical reactions between primary pollutants (ozone, smog).
Photochemical smog: Secondary pollutant mix formed when NOₓ and VOCs react in sunlight; produces ground-level ozone.
Acid rain: Precipitation with pH below 5.6, formed when SO₂ and NOₓ dissolve in atmospheric moisture.
Particulate matter: Tiny solid or liquid particles suspended in air; penetrate lungs and damage respiratory and cardiovascular systems.
Stratospheric ozone: Layer of O₃ in the stratosphere that absorbs UV-B radiation and protects life on Earth.
CFCs (chlorofluorocarbons): Synthetic compounds that destroy stratospheric ozone; regulated by the Montreal Protocol.
Montreal Protocol (1987): International treaty phasing out ozone-depleting substances; one of the most successful environmental treaties.
Clean Air Act: U.S. law (1963, amended 1970, 1990) setting air quality standards to protect public health.
Hydraulic fracturing (fracking): Method of extracting oil or gas by injecting high-pressure fluid into rock formations; raises groundwater and air quality concerns.

The concept

Fossil fuels — coal, oil, and natural gas — formed from ancient organic matter compressed over millions of years. They are nonrenewable on human timescales. EROI (Energy Return on Investment) measures how much energy a fuel provides relative to the energy required to extract it. Oil's EROI has declined as easy-to-access reserves are depleted.

Combustion of fossil fuels releases primary air pollutants: SO₂, NOₓ, particulate matter, CO, and CO₂. Primary pollutants react in the atmosphere to form secondary pollutants — photochemical smog (from NOₓ + VOCs + sunlight) and acid rain (from SO₂ and NOₓ dissolving in atmospheric moisture). Acid rain damages forests, acidifies lakes, and corrodes buildings.

The ozone layer in the stratosphere absorbs harmful UV-B radiation. Chlorofluorocarbons (CFCs) from old refrigerants and aerosols catalytically destroy stratospheric ozone molecules. The Montreal Protocol (1987), an international treaty phasing out CFCs, is widely considered one of the most successful environmental agreements. The Clean Air Act sets National Ambient Air Quality Standards for six criteria pollutants.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. Photochemical smog is classified as a secondary air pollutant because:

2. Acid rain has a pH below 5.6. It forms when:

3. The stratospheric ozone layer is important for life on Earth because:

4. CFCs were used in refrigerants and aerosols. They damage the ozone layer by:

5. The Energy Return on Investment (EROI) ratio measures:

Canvas is the official record. This companion enhances the PGCC curriculum; it does not replace it. Last name and class year only. Students with a 504 plan or IEP: your accommodations apply.

↑ Back to top