ppt about topospheric pollution

2. AIR POLLUTION OCCURS WHEN HARMFUL SUBSTANCES INCLUDING PARTICULATES AND BIOLOGICAL
MOLECULES ARE INTRODUCED INTO EARTH'S ATMOSPHERE. IT MAY CAUSE DISEASES, ALLERGIES OR
DEATH OF HUMANS; IT MAY ALSO CAUSE HARM TO OTHER LIVING ORGANISMS SUCH AS ANIMALS AND
FOOD CROPS, AND MAY DAMAGE THE NATURAL OR BUILT ENVIRONMENT. HUMAN ACTIVITY AND
NATURAL PROCESSES CAN BOTH GENERATE AIR POLLUTION.
INDOOR AIR POLLUTION AND POOR URBAN AIR QUALITY ARE LISTED AS TWO OF THE WORLD'S WORST
TOXIC POLLUTION PROBLEMS IN THE 2008 BLACKSMITH INSTITUTE WORLD'S WORST POLLUTED PLACES
REPORT. ACCORDING TO THE 2014 WORLD HEALTH ORGANIZATION REPORT, AIR POLLUTION IN 2012
CAUSED THE DEATHS OF AROUND 7 MILLION PEOPLE WORLDWIDE, AN ESTIMATE ROUGHLY ECHOED BY
ONE FROM THE INTERNATIONAL ENERGY AGENCY.
Introduc
tion

3. Spheresoftheearth

4. The troposphere is the lowest layer of Earth's atmosphere, and is also where nearly all weather
conditions take place. It contains approximately 75% of the atmosphere's mass and 99% of the total mass
of water vapor and aerosols. The average depths of the troposphere are 20 km (12 mi) in the tropics, 17 km
(11 mi) in the mid latitudes, and 7 km (4.3 mi) in the polar regions in winter. The lowest part of the
troposphere, where friction with the Earth's surface influences air flow, is the planetary boundary layer. This
layer is typically a few hundred meters to 2 km (1.2 mi) deep depending on the landform and time of day.
Atop the troposphere is the tropopause, which is the border between the troposphere and stratosphere. The
tropopause is an inversion layer, where the air temperature ceases to decrease with height and remains
constant through its thickness.
Introductionoftroposphere

5. WhyareweInterestedinTropospheric
Ozone?
• Environmental impacts on local, regional and global scales
• Secondary pollutant: sensitive to many variables
– Chemical production can be fast in polluted conditions
– Lifetime is sufficiently long for global-scale transport

6. SOURCESOFTROPOSPHERICOZONE

7. GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-PRESENT [IPCC, 2001] (INTERGOVERNMENTAL PANEL ON CLIMATE
CHANGE)
CLIMATEFORCINGBYAIRPOLLUTANTS

8. EffectonTroposphericCO
andO3 • Inverse modeling using the
MOZART CTM(Model
for Ozone And Related
chemical Tracers) showed that
the fires emitted about as
much CO as did human-
related activities
• Because of the wildfires,
ground-level concentrations
of O3 increased by 25% or
more

9. PROCESSESCONTROLLINGTROPOSPHERICO3

11. The“GreenhouseEffect”
The Earth’s surface thus receives energy from two
sources: the sun & the atmosphere
– As a result the Earth’s surface is ~33C warmer than it
would be without an atmosphere
Greenhouse gases are transparent to shortwave but
absorb longwave radiation
– Thus the atmosphere stores energy

13. 1. Shorter, high
Energy wavelengths
Hit the earths
Surface
2. Incoming energy
Is converted to heat

14. 3. Longer, infrared
Wavelengths hit
Greenhouse gas
Molecules in the
atmosphere
4. Greenhouse gas
Molecules in the
Atmosphere emit
Infrared radiation
Back towards earth

15. AbsorptionSpectraofAtmospheric
Gases

16. SelectedGreenhouse
Gases• Carbon Dioxide (CO2)
– Source: Fossil fuel burning, deforestation
 Anthropogenic increase: 30%
 Average atmospheric residence time: 500 years
 Methane (CH4)
– Source: Rice cultivation, cattle & sheep ranching, decay
from landfills, mining
 Anthropogenic increase: 145%
 Average atmospheric residence time: 7-10 years
 Nitrous oxide (N2O)
– Source: Industry and agriculture (fertilizers)
 Anthropogenic increase: 15%
 Average atmospheric residence time: 140-190 years

17. GreenhouseEffect&Global
Warming• The “greenhouse effect” & global
warming are not the same thing.
– Global warming refers to a rise in the
temperature of the surface of the earth
• An increase in the concentration of
greenhouse gases leads to an
increase in the the magnitude of the
greenhouse effect. (Called enhanced
greenhouse effect)
– This results in global warming

18. Variability
Average
ClimateChangevs.Variability

19. GlobalEnergyRedistribution

20. Radiation is not evenly distributed over the
Surface of the earth. The northern latitudes have an
energy deficit and the low latitude/ equator has an
excess. But the low latitudes don’t indefinitely get
hotter and the northern latitudes don’t get colder.
Why?
The atmosphere and ocean transfer energy from low
latitudes to high

21. The greenhouse effect is the process by which radiation from a planet's atmosphere warms
the planet's surface to a temperature above what it would be without its atmosphere.
If a planet's atmosphere contains radioactive gases (i.e., greenhouse gases) they will radiate
energy in all directions. Part of this radiation is directed towards the surface, warming it. The
intensity of the downward radiation – that is, the strength of the greenhouse effect – will
depend on the atmosphere's temperature and on the amount of greenhouse gases that the
atmosphere contains.
Earth’s natural greenhouse effect is critical to supporting life. Human activities, mainly the
burning of fossil fuels and clearing of forests, have strengthened the greenhouse effect and
caused global warming.
The term "greenhouse effect" arose from a faulty analogy with the effect of sunlight passing
through glass and warming a greenhouse. The way a greenhouse retains heat is
fundamentally different, as a greenhouse works mostly by reducing airflow so that warm air is
kept inside.
Greenhouse
effect

23. Summary
Greenhouse gases absorb infrared radiation and prevent
it from escaping to space.
Carbon dioxide, methane, and nitrous oxide are very
good
at capturing energy at wavelengths that other
compounds
miss