9. Chemistry of the Atmosphere

What is the composition of the Earth's atmosphere today?

About 80% nitrogen, 20% oxygen, and small amounts of carbon dioxide, water vapor, and noble gases.

What gases mainly made up the Earth's early atmosphere?

Mostly carbon dioxide, with some nitrogen, methane, ammonia, and water vapor from volcanic activity.

How did oxygen increase in the Earth's atmosphere?

Oxygen was produced by algae and plants via photosynthesis starting about 2.7 billion years ago.

How did carbon dioxide levels decrease over time?

Photosynthesis by plants and algae and the formation of sedimentary rocks and fossil fuels reduced atmospheric CO2.

What are greenhouse gases?

Gases like water vapor, carbon dioxide, and methane that trap heat in the atmosphere to maintain Earth's temperature.

Name two human activities that increase carbon dioxide levels.

Burning fossil fuels and deforestation.

Name two human activities that increase methane levels.

Agriculture (livestock) and landfill sites.

What are some potential effects of global climate change?

Sea level rise, extreme weather, loss of habitats, and changes in ecosystems.

What is a carbon footprint?

The total amount of greenhouse gases emitted over the full life cycle of a product, service, or event.

How can the carbon footprint be reduced?

By reducing emissions of carbon dioxide and methane through changes in lifestyle and technology.

What pollutants are released by burning fuels?

Carbon dioxide, water vapor, carbon monoxide, sulfur dioxide, nitrogen oxides, soot, and unburned hydrocarbons.

Why is carbon monoxide dangerous?

It is toxic, colorless, and odorless, making it hard to detect.

What problems do sulfur dioxide and nitrogen oxides cause?

They cause respiratory problems in humans and acid rain.

What problems do particulates cause?

Global dimming and health issues for humans.