DNA – answer and defend
The breakdown of the ozone layer is
dangerous because it absorbs less
(A) UV radiation
(B) CFCs
(C) Acid rain
(D) Water vapor
(E) Nitrogen
1
UNIT 9: AIR
POLLUTION
How do we make the air in
our community safe to
breathe?
Agenda
1.
2.
3.
4.
5.
DNA
N – Air pollution pt 4
A – ESA 21 / FRQ
N – Air pollution pt 5
L/A – CO2 in ERHS classrooms
3
Homework
•Work
on your study guide!! Focus on air
pollution legislation! Unit test 3/26 ; 3/27
•Unit review 3/25
4
Control of SO2 emissions
•Combustion
of coal using the “fluidized
bed combustion” method reduces SO2
emissions.
•Fluidized bed combustion is when coal is
burned in close proximity to calcium
carbonate (CaCO3).
•The CaCO3 absorbs SO2 and produces
calcium sulfate
5
Control of NO emissions
•More
NO is produced the hotter
combustion is. Reducing burn
temperatures and oxygen supply can
reduce NO.
•NO emissions from cars have reduced
because cars after 1975 are required to
have catalytic converters, which reduce
the NO and CO emissions.
6
Control of PM emissions
•Electrostatic precipitators
•Particles become negatively charged
and then attracted to positively charged
plates
•Baghouse filters
•Filter bags physically filter out the particles
•Scrubbers
7
Focus on: scrubbers
1.
2.
3.
4.
Dirty air enters scrubber
Polluted air passes
through a layer of steam
that traps particles
within the droplets
Polluted droplets are
collected inside a filter
Clean air leaves
8
With your elbow partner:
•The
activated carbon in the “Cleaner
Air and Water on the Fly” acted like
what part of a wet scrubber?
9
Review:
•What
are the major air
pollutants?
10
Clean Air Act of 1970
•Requires
the EPA to set National
Ambient Air Quality Standards
(NAAQS) for air pollutants considered
harmful to public health and the
environment
•(Set emission standards for cars, and
limits for release of air pollutants)
11
Clean Air Act of 1970
•Regulates
•
•
•
•
SO2
No2
CO
PM
criteria air pollutants:
• Tropospheric
ozone (O3)
• Lead
12
Indoor air pollution
•Significant
problem in developing
countries
•Problem is present in developed
countries
•Exposure to pollutants in a confined
space can be a significant health risk!
13
Developing countries
•Burning
wood, animal manure or coal indoors
for heat and cooking
•Lack of ventilation makes indoor air pollution
from CO and PM a hazard in developing
countries!
•WHO estimates that indoor air pollution is
responsible for 1.6 million deaths annually
worldwide
14
Indoor air pollution in developed countries
•An
increasing issue b/c:
•People
are spending more time
indoors
•Better insulation = air stays inside for
longer amounts of time
•Change in materials we use to
construct houses
15
Sick Building Syndrome
•Improved
insulation allows buildup of toxic
compounds and pollutants in buildings = sick
building syndrome
•New or renovated buildings usually because
their synthetic materials and glues may
release high values of VOCs
•SBS observed in office buildings where large
numbers of workers feel sick
16
Asbestos
•Used
as an insulator for many years in
homes
•Fibers become airborne and significantly
increase risk of developing lung cancer
and respiratory diseases such as
asbestosis
•Even after removal from a home, fibers
can last in air for up to a year!
17
Radon
•Radioactive
gas that occurs naturally from
the decay of Uranium
•EPA estimates about 21,000 people die each
year from radon-induced lung cancer
•EPA suggests people test their homes for
airborne radon
•(Low risk to moderate risk in CA, high in
Wyoming!)
18
Smog City OR CO2 in classrooms lab
•Complete
smog city
•Take
CO2 readings for at least 4
classrooms (in your groups)
19