Bellringer

Bellringer

•Define “air pollution”.

•What types of things count as “air pollution”?

•What does polluted air look like?

•What do you think is the biggest source of air pollution in cities?

#15 - What Causes Air #15 - What Causes Air Pollution? Pollution? Section 12.1Section 12.1

Objectives:Objectives:

1.1. Name 5 primary air Name 5 primary air pollutants, and give sources pollutants, and give sources

for each.for each.

2.2. Name the 2 major sources of Name the 2 major sources of air pollution in urban areas.air pollution in urban areas.

3.3. Describe how smog forms.Describe how smog forms.

Define “air pollution”Define “air pollution”

•When harmful substances build up in the air to unhealthy levels.– Human activities– Natural sources

•Compare cigarette smoke and pollution (Lanzhou, China)

•Cigarette manufacturers vs. industries – legal responsibilities

Primary and Secondary Primary and Secondary PollutantsPollutants

• Primary pollutants: a pollutant put directly into the air by human activity (EX: soot from smoke)

• Secondary pollutant: forms when a primary pollutant comes into contact with other primary pollutants or with naturally occurring substances, such as water vapor, and a chemical reaction takes place (EX: ground-level ozone formed from vehicle emissions reacting with UV rays and mixing with oxygen)

What color is polluted What color is polluted air?air?• Primary Air Pollutants (Table 1, p.304)

Sources of Primary Air Sources of Primary Air Pollutants Pollutants

(Fig.1, p.303)(Fig.1, p.303)

SmogSmog

• Definition: pollution that hangs over urban areas and reduces visibility

• Smog is formed when:

1. Car emissions combine with sunlight and air to form ozone.

2. Car emissions + ozone = smog

• What is the importance of ozone alerts?

• “Valley of the Smokes” - LA

Temperature InversionTemperature Inversion

•How does temperature change with elevation?

•When warm air rises, it carries air pollutants with it, removing them from air at the surface.

•Temperature inversion: the air above is warmer than the air below.

•The warmer air above traps the cooler air (and pollutants) at the surface.

Reducing Air PollutionReducing Air Pollution

•King Edward II (1273): “Off with his head!”

•What attempts can you think of that have been used to try to reduce air pollution?

Regulating Motor Vehicle Emissions

•Clean Air Act (1970; 1990)– EPA regulates vehicle emissions– Leaded gasoline

•Zero-Emission Vehicle Programs– Electric vehicles– Advanced battery vehicles– Hydrogen fuel– Partial zero-emissions vehicles

Industrial Air Pollution

•How do factories and power plants make electricity?

•Power plants the produce electricity ALSO produce 2/3 of all sulfur dioxide and 1/3 of all nitrogen oxides that pollute the air.

•Clean Air Act requires many industries to “scrub” or filter their emissions – spray the gases with water to dissolve pollutants.

Group DiscussionGroup Discussion

•How do you contribute to air pollution?

•At what point would the level of air pollutants be high enough for you to take action?

•Should automobile makers be made to adhere to quotas of zero-emission vehicles set by states, even if the quota causes automakers to lose revenues? Support your stand.

ReviewReview

• On the board, list as many causes of air pollution as possible.

• Exit Slip Assignment: Place the causes in the appropriate category. (NOTE: Causes may fall into more than one category.):

1. Industrial and Commercial2. Transportation3. Noncommercial

KNOW FOR TEST!!!KNOW FOR TEST!!!

•Section Review questions 1-4 (p.308)