AP Environmental Science: Atmospheric Dynamics & Pollution

Air Pollution

The introduction of chemicals, particulate matter, or biological materials into the atmosphere that cause harm or discomfort to humans or other living organisms.

Primary Pollutants

Compounds that come directly out of a smokestack, exhaust pipe, or natural emission source.

Examples of Primary Pollutants

Carbon Monoxide (CO), Nitrogen Oxides (NOx), Sulfur Dioxide (SO2), Particulate Matter (PM), and Volatile Organic Compounds (VOCs).

Secondary Pollutants

Primary pollutants that have undergone transformation in the presence of sunlight, water, oxygen, or other compounds.

Examples of Secondary Pollutants

Ozone (O3), Sulfuric Acid (H2SO4), Nitric Acid (HNO3), and Peroxyacyl Nitrates (PANs).

Clean Air Act (CAA)

A regulation that requires the EPA to set National Ambient Air Quality Standards for specific criteria pollutants.

Criterion Pollutants

The six primary air pollutants regulated under the Clean Air Act: SO2, PM, Pb, O3, NO2, and CO.

SPLONC Mnemonic

An acronym to remember the six criteria pollutants: Sulfur Dioxide, Particulate Matter, Lead, Ozone, Nitrogen Dioxide, Carbon Monoxide.

Photochemical Smog

A type of air pollution that occurs when nitrogen oxides and volatile organic compounds react with sunlight.

Ingredients for Photochemical Smog

NOx (NO and NO2), VOCs, and sunlight.

Pollutant Formation Reaction

NO2 + sunlight → NO + O, with O combining with O2 to form O3.

Thermal Inversion

A weather condition in which a warm layer of air traps pollutants near the surface of the earth.

Impacts of Thermal Inversion

Prevents the vertical dispersal of pollutants leading to increased air pollution near the ground.

Geographical Factors of Inversion

Valleys are most susceptible to thermal inversion because mountains block horizontal airflow.

Particulate Matter (PM)

Solid or liquid particles suspended in the air that can affect health.

PM10 vs PM2.5

PM10 particles are ≤10 micrometers, while PM2.5 particles are ≤2.5 micrometers and more dangerous.

Sources of PM

Natural sources include volcanoes and wildfires, while anthropogenic sources include combustion and agriculture.

Carbon Dioxide (CO2) as a Pollutant

A gas that can be toxic in high concentrations due to environmental displacement.

Natural Sources of CO2

Respiration, decomposition, and volcanic eruptions.

Anthropogenic Sources of CO2

Fossil fuel combustion and deforestation.

Seasonal Variations of CO2

CO2 levels fluctuate seasonally, influenced by photosynthesis during warmer months.

Good Ozone vs Bad Ozone

Stratospheric ozone is good (blocks UV), while tropospheric ozone is bad (damages lungs).

Ozone Depletion vs Climate Change

Ozone depletion relates to UV radiation risk, while climate change involves greenhouse gases trapping heat.

Photochemical vs Industrial Smog

Photochemical smog is nitrogen-based (NOx) while industrial smog is sulfur-based (SO2).

Asthma

A respiratory condition exacerbated by air pollution.

Ozone and Plant Damage

Ozone can oxidize plant tissue and inhibit photosynthesis.