Chapter 3 Earth's Atmosphere - Vocabulary Flashcards

Vocabulary flashcards covering key terms and concepts from the Earth's atmosphere lecture.

Exosphere

Top of Earth's atmosphere; near vacuum; essentially no air.

Troposphere

Lowest atmospheric layer; contains ~90% of the atmosphere's mass; weather occurs; temperature generally decreases with altitude.

Stratosphere

Layer above the troposphere where temperature rises with altitude due to UV absorption by ozone.

Mesosphere

Middle layer; noctilucent clouds form here; ice crystals form around dust particles, high in the atmosphere.

Thermosphere

Upper atmospheric layer; very low density; extremely hot; often called the 'Heat Sphere'.

Heterosphere

Upper part of the atmosphere where gases are layered by gravity; contains less than 0.001% of the atmosphere’s mass.

Homosphere

Lower atmospheric layer dominated by N and O; ozone and trace gases present.

Ozonosphere

Region containing the ozone layer; ozone (O3) absorbs UV energy and heats the layer.

Ozone hole

Seasonal depletion area in the ozone layer; recovery projected around 2060–2070.

CFCs (Chlorofluorocarbons)

Refrigerants; UV light releases chlorine that destroys ozone; worldwide ban in 1987.

Ionosphere

Atmospheric region where ions form from high-energy radiation; essential for radio communications and GPS.

Pollutant

Natural or human-caused gas, particle, or substance harmful to humans or the environment, primarily in the troposphere.

Anthropogenic pollutant

Pollutants produced by human activities (e.g., CO, NOx, VOCs, SO2, PM).

Natural pollutant

Pollutants arising from natural sources (e.g., volcanoes, wildfires, dust).

Carbon Monoxide (CO)

Colorless, odorless gas from incomplete combustion; toxic because it displaces oxygen in the blood.

Photochemical smog

Smog formed when UV light reacts with exhaust pollutants to produce ozone, NO2, and other compounds.

Industrial smog

Smog arising from coal burning; high CO2, particulates, and sulfur oxides.

Particulate matter (PM)

Mixture of fine solid and liquid particles (aerosols); includes PM2.5 and PM10; health impacts.

NOx (Nitrogen oxides)

NO and NO2; from combustion; contribute to smog, ozone formation, and respiratory irritation.

VOCs (Volatile Organic Compounds)

Reactive hydrocarbons; emitted from solvents, fuels, and industry; precursors to ozone.

Ground-level ozone (O3)

Ozone near the Earth's surface; formed by photochemical reactions; a key smog pollutant.

PANs (Peroxyacetyl nitrates)

Secondary pollutant formed in photochemical smog; irritates eyes and respiratory system.

SO2 (Sulfur dioxide)

Gas from burning sulfur-containing fuels; irritates airways and leads to acid deposition.

PM2.5

Particulate matter with diameter ≤ 2.5 microns; can penetrate deep into lungs.

PM10

Particulate matter with diameter ≤ 10 microns; can irritate eyes and respiratory tract.

Clean Air Act

US law (amended 1970, 1977, 1990) regulating air emissions from stationary and mobile sources; improves air quality.

Temperature inversion

Layer where temperature increases with height, trapping pollutants near the surface.

Lapse rate

Rate at which air temperature decreases with altitude (about 6.4 °C per 1000 m).