Urban heat islands

Human Effects on Air Quality

⦿ Air Pollution: contamination of air due harmful substances in the atmosphere

○ Can be man-made or natural
○ Hurts humans, other organisms, & the climate

Sources of Pollution

⦿ Stationary sources:: coal, power plants, industrial factories

⦿ Mobile sources: cars, planes, ships

⦿ Fumes: aerosols, paint, hair spray

⦿ Waste Deposition: landfills create harmful gases as waste breaks down

Main Types of Pollutants
⦿ Carbon Oxides – created by volcanoes and combustion engines.

⦿ Sulfur Oxides – created by volcanoes and factories.

⦿ Nitrogen Oxides – created by burning coal, gasoline and oil in cars, homes,
industries and power plants.

Sulfur dioxide (SO2) and nitrogen oxides
(NOx) can combine to form acid rain.

Acid Rain

⦿ SO2 + NOx = acid rain

⦿ Global warming & climate change

increase rxns between pollutants → increases amount of acid rain

⦿ Acid rain dissolves important nutrients in soil,

weathers rocks, & causes health problems in humans, animals, and plants

Main Types of Pollutants (pt. 2)

⦿ Particulates: airborne solids; can cause cancer

⦿Chlorofluorocarbons: (CFCs): a pollutant found in aerosols, breaks down the ozone layer

Increase CFCs → decrease ozone → increase in harmful UV radiation & health risks

Ground-Level Ozone

⦿ Ground-level ozone is a gas that forms just above the earth's surface.

• Created when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react.

  • VOCs mainly come from the burning of gasoline
    
    

⚫

Ground-level ozone causes an increase in global temperatures → global warming!!

Ground
-Level
Ozone

URBAN HEAT ISLANDS

How do humans & our cities affect Earth’s climate?

Why is it hotter in cities during the summer?

Darker colored objects absorb

MORE heat!

Let’s see how this relates to temperatures in cities!

URBAN HEAT ISLANDS

● City structures, like buildings and roads, absorb the sun’s heat more than natural/rural landscapes such as forests and bodies of water.

● Urban areas become “islands” of higher temp. compared to rural areas.

● In the United States, the heat island effect results in daytime temperatures in urban areas about 1–7°F higher than temperatures in rural areas

URBAN HEAT ISLAND EFFECTS

● Increase the need for electricity to power air conditioning

• Companies that supply electricity rely on fossil fuels & power plants which leads to an increase in air pollution and greenhouse gas emissions

  • Increases ground-level ozone (smog) and acid rain.

  • contributes to global climate change

Now time to practice!

Use the link on Canvas to help you answer questions

​ https://www.epa.gov/heatislands/learn-about-heat-islands