Post on 10-Jul-2020
transcript
Air and Air Pollution
These slides are adapted from the Glencoe
Earth Systems Textbook for CCSD use only
and the EPA’s Air pollution website
What Causes Air Pollution?
▪ Reflection: List 5 things you think
cause air pollution.
What resources are in our air?
▪ Mixture of gases
– 78% nitrogen
– 21% oxygen
– 1% argon, carbon
dioxide, water vapor
Key Problems With Air
▪ Air pollution can harm human health and the
environment
▪ It can be harmful even when it is not visible
▪ Many countries have no laws in place to
protect their air
▪ Laws do not guarantee compliance
▪ Difficult if not impossible to clean once
polluted
Sources of Air Pollution
Natural sources
▪ Sand
▪ Dust storms
▪ volcanic eruptions
▪ forest fires
▪ Solar activity
Human sources
▪ burning fossil fuels
▪ factory and car
emissions,
▪ refrigerators and
air conditioners
Map of Air Pollution (red)
History Of Human Air Pollution▪ pre-1700s – burning of wood, coal,
animal dung, or other biofuels for cooking
and heat
▪ Industrial revolution (1700’s) –
widespread burning of wood and coal for
fuel
▪ Modern times – trash incineration and
modern chemicals introduced into the air
supply
How do we categorize air
pollutants?
▪ Primary = put directly
into the air by humans
▪ Secondary = when
chemicals react with
other substances in
the air to make
pollutants
Outdoor pollutants
1. Particulates, such as ash, dust, soot, plant
pollen
2. Gases – usually oxides, that are released
when fossil fuels are burned
3. Smog – ground-level ozone (O3) and particulate matter
4. Chlorofluorocarbons (CFC’s): once used in refrigerators, ac’s, aerosol cans, and the production of foams
5. Airborne Lead – still released in the US by certain factories
What kind of pollutant is smog?
Indoor Pollutants
Dangerous because of poor air circulation and the long amounts of time people spend inside
1. Cigarette smoke – deadliest of all
2. Microorganisms – bacteria and fungi from air ducts and vents
3. Radon – radioactive gas – comes from soil when radium breaks down
4. Asbestos – minerals that form in long thin fibers – banned in US
Temperature Inversions
▪ When weather conditions
create a trap for air so that
it cannot rise or circulate
▪ Prevents pollutants from
escaping into the
atmosphere
▪ Makes people more likely
to suffer from allergies
and pollution-related
conditions
Human Health Effects
▪ Carbon monoxide replaces oxygen
in the bloodstream
▪ Ozone and oxides – irritate eyes
and respiratory tract
▪ Particulates and asbestos cause
lung diseases, such as Emphysema
and Mesothelioma, lung cancer
– Lung Cancer – 150,000 deaths per year
in US
Ecosystem Effects
▪ Ozone is hazardous to plants, cause stems to be brittle and leaves spotted
▪ Air pollution destroys crops– US loses $1 billion of crops and
plants per year (Auburn University Research)
▪ Same health problems for animals as for humans
Natural Cleaning and Regulation
of Air
▪ Precipitation sticks to pollutant particles
and fall to the ground
▪ Plants and plankton remove excess
CO2 and help keep the planet cool
▪ Electric cars, hybrid cars
– Zero Emissions Vehicles – no tailpipe emissions
▪ Legislation (EPA)– Clean Air Act 1970
▪ Set federal limits on 6 primary air pollutants: particulates, ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead
Requires:▪ Pollution control devices in factories, such as
scrubbers, which remove pollutants from exhaust
▪ States to create a plan to reduce air pollution and meet these standards
▪ Motor vehicle regulation to reduce exhaust pollution
Human Solutions to Air Pollution
Acid Rain
▪ Precipitation that is more acidic than normal
(anything < pH 5.6)
– Water in the atmosphere reacts with gases
released from factories
– Falls and builds up in lakes
▪ Canada-US Air Quality Agreement in 1991
– Agreed to:
▪ Reduce SO2 and NOx emissions
▪ Collaborate on acid-rain scientific research
▪ Share new technologies that reduce human-caused
acid rain
Noise Pollution
▪ Any unwanted sound
▪ Airplanes, machinery, loud concerts, etc.
▪ Sound measured in decibels – 70-80 dB = annoyance, hearing
loss
– 120 – 130 dB = physical pain and hearing damage
▪ Noise Control Act 1972 – sets standards for maximum noise levels in workplace
Light Pollution
▪ Not a direct health
hazard but
environmental
hazard
When lights are pointed upward (billboards, buildings),
blocking the night sky
Poor quality street lights can be upgraded
Lights can be put on timers