Earth’s Atmosphere

The Air Sphere

Gases in the Air

• Many gases make up the air we breathe– Nitrogen (78%)– Oxygen (20%)– Water Vapour (0-4%)– Carbon Dioxide (0.036%) – Methane, Nitrous Oxide, Ozone (< 0.001%)

Where do these gases come from?

Cellular Respiration•A process used by animals to produce energy from food that is consumed

Consumed ReleasedOxygen + sugar carbon dioxide + water + energy

Products of Cellular respirationsteam (water vapour) and carbon dioxide

Where do these gases come from?

Photosynthesis•Process used by plants to produce energy•Energy from sunlight is captured using chlorophyll and used to produce sugars

Consumed ReleasedCarbon dioxide + water sugars + oxygen

Natural Balance• Cellular respiration requires oxygen and

produces carbon dioxide– Animals breathe in oxygen, and exhale carbon

dioxide

• Photosynthesis requires carbon dioxide and produces oxygen– Plants absorb carbon dioxide and release oxygen

Air PollutionCombustion• Energy from hydrocarbons (fossil fuels, gasoline,

natural gas) is used to power vehicles, heat homes, produce electricity etc.

Hydrocarbon + oxygen carbon dioxide + water

• Burning fossil fuels requires oxygen, and produces carbon dioxide which is released into the atmosphere

Air Pollution Sources in Canada• Vehicle Emissions• Industrial Sources (factories)• Energy Production (for electricity and heating)• Livestock and fertilizers

In 2009, Canada emitted 521 megatons of CO2

• that’s 521 million tons of carbon dioxide released into the atmosphere in one year

Ontario’s Energy, Nanticoke Power Plant

• North America’s largest coal-fired power plant• Produced more than 8 million tonnes of carbon

dioxide in 2010

Greenhouse Effect

Greenhouse Effect• Greenhouse gases (GHG’s) trap and re-radiate heat

from the sun back towards Earth

• This is normal (to some extent), keeps Earth warm enough for life

• Greenhouse Gases– Water vapour– Methane– Carbon dioxide– Ozone– Carbon monoxide

Greenhouse Effect with Pollution

Solutions to Reduce Air Pollution• Reduce carbon dioxide emissions– Hybrid-electric vehicles use burn less gasoline– Fully-electric vehicles use no gasoline– Stop burning fossil fuels for energy (use solar or

wind power instead)

• Remove carbon dioxide from the atmosphere– Planting trees helps capture and store carbon

dioxide by photosynthesis

Reduce Carbon Dioxide• Hybrid-Electric Vehicles burn less gasoline

than conventional vehicles

Reduce Carbon DioxideFully-Electric Vehicles burn no gasoline

Fully-electric Tesla Model S

Reduce Carbon Dioxide• Stop burning fossil fuels to produce energy• Switch to wind, solar, hydro power

Wind Turbine, Toronto’s Lakeshore

Remove Carbon Dioxide• Planting trees helps capture and store carbon

dioxide by photosynthesis