Chemistry of the Atmosphere

What are the current approximate proportions of gases in Earth's atmosphere?

• ~80% nitrogen

• ~20% oxygen

• Small amounts of other gases, including carbon dioxide, water vapor, and noble gases

How did Earth's early atmosphere differ from today's atmosphere?

• Dominated by carbon dioxide

• Little or no oxygen present

• Contained water vapor, nitrogen, and small amounts of methane and ammonia

What role did volcanic activity play in shaping Earth's early atmosphere?

• Released large quantities of gases, including carbon dioxide, water vapor, and nitrogen

• Contributed to the formation of the early atmosphere

How did the formation of oceans influence atmospheric carbon dioxide levels?

• Water vapor condensed to form oceans

• Carbon dioxide dissolved in oceans, forming carbonate compounds

• Led to a decrease in atmospheric carbon dioxide levels

How did photosynthetic organisms affect Earth's atmosphere?

• Algae and plants produced oxygen through photosynthesis

• Increased atmospheric oxygen levels

• Decreased atmospheric carbon dioxide levels

How did nitrogen (N₂) become a major gas in the Earth's atmosphere?

• Early volcanoes released ammonia (NH₃) along with other gases.

• Ammonia was broken down by sunlight in the atmosphere.

• This process released nitrogen gas (N₂).

• Nitrogen is unreactive, so it built up in the atmosphere over time.

What are greenhouse gases, and how do they affect Earth's temperature?

• Gases that trap heat in Earth's atmosphere

• Contribute to the greenhouse effect, warming the planet

Name two primary greenhouse gases.

• Carbon dioxide (CO₂)

• Methane (CH₄)

List human activities that increase atmospheric carbon dioxide levels.

• Burning fossil fuels (coal, oil, natural gas)

• Deforestation

• Industrial processes

List human activities that increase atmospheric methane levels.

• Agriculture (e.g., rice cultivation, livestock digestion)

• Landfills

• Extraction and transport of fossil fuels

What are potential consequences of increased greenhouse gas concentrations?

• Global warming

• Climate change

• Rising sea levels

• Extreme weather events

What is a carbon footprint?

Total amount of greenhouse gases emitted directly and indirectly by an individual, organization, event, or product.

How is carbon monoxide produced, and why is it dangerous?

• Produced by incomplete combustion of carbon-containing fuels (lack of oxygen)

• Colorless, odorless gas

• Binds to hemoglobin, reducing oxygen transport in the blood which can cause suffocation or death

What are the environmental effects of sulfur dioxide emissions?

• Contributes to acid rain formation

• Damages vegetation, aquatic ecosystems, and infrastructure

How are nitrogen oxides produced, and what environmental problems do they cause?

• Produced by high-temperature combustion in vehicles and power plants

• Contribute to smog formation

• Lead to acid rain

• Cause respiratory problems

What is particulate matter, and what are its health impacts?

• Tiny solid or liquid particles suspended in the air

• Can penetrate deep into the lungs

• Cause respiratory and cardiovascular issues

How can atmospheric pollution from vehicles be reduced?

• Use of catalytic converters

• Adoption of electric or hybrid vehicles

• Implementation of stricter emission regulations

What are the effects of unburned hydrocarbons in the atmosphere?

• Contribute to the formation of ground-level ozone

• Lead to smog formation

• Cause respiratory health issues