Transcript Understanding Weather and Climate Ch 5

Air Pollution
Review of last lecture
• Effects of different surface types: desert, city, grassland,
forest, sea. Deeper heat/water reservoir, decreased
Bowen ratio, thinner BL and enhanced convective
instability.
• Effects of vegetation: (1) makes heat/water reservoir
deeper, (2) enhance evaporation, (3) grows and dies in
response to environmental conditions
• Heat island effect. 7 causes
• Dispersion of air pollution. Dependence on wind speed,
stability (name of 3 types) and inversion (name of 2
types)
• Global atmosphere/ocean circulation: linking the world
together. Therefore we need to protect the environment.
Effects of human activities
Human beings are changing the global climate system in
three different ways:
• Change land cover (deforestation and afforestation)
• Release or cleanse pollutants (aerosols)
• Release or cleanse greenhouse gases
Introduction
• Air pollutants are gases, liquids or solids in the air that
can adversely affect plant and/or animal life.
• Primary pollutants are pollutants that are emitted
directly by natural or anthropogenic (manmade)
processes.
• Secondary pollutants are pollutants that arise
from chemical reactions of atmospheric gases with
gases emitted by natural or anthropogenic
processes.
Major pollutants: (1) Particulates
• Particulates (aerosols) are solid or
liquid matter suspended in the air
(from 0.1 to 100 µm in size).
• Natural sources: natural fires,
volcanic eruptions, salt spray from
the oceans, pollen.
• Anthropogenic sources: burning of
fossil fuels.
• Although particulates can remain in
the air for some time due to their
small size, rain removes them.
• PM10 (<10 µm) enters lungs
(associated with asthma); PM2.5
even more dangerous (lung cancer).
Major pollutants: (2) Carbon Oxides
• Carbon monoxide (CO) is a
colorless, odorless gas from
volcanic eruptions, forest fires
and other processes.
• Extremely toxic and dangerous
to humans and animals.
• Carbon dioxide (CO2) is an
important greenhouse gas but
is officially considered a
pollutant by the US EPA.
Threshold levels of carbon monoxide
Major pollutants: (3) Sulfur Compounds
• Sulfur compounds can occur as
gaseous or aerosol forms.
• Natural sources: steam vents,
volcanic eruptions, sea spray.
• Anthropogenic sources: burning
sulfur containing fossil fuels
(particularly coal and oil) and ore
smelting.
• Sulfur dioxide (SO2) is a
respiratory irritant.
• Sulfur trioxide (SO3)
contributes to acid fog and
acid rain.
Averaged PH values of precipitation
(Acid precipitation)
Major pollutants: (4) Nitrogen Oxides (NOX)
• Nitric oxide (NO) is a nontoxic,
colorless, and odorless gas.
• Natural sources: biological
processes in soil and water.
• Nitrogen dioxide (NO2) is a
toxic, yellow to reddish-brown gas
that is pungent and corrosive.
• Provides polluted air with the
yellow to reddish brown
color.
• Anthropogenic sources:
Vehicle traffic.
• Can cause pulmonary health
problems.
Major pollutants: (5) Volatile Organic
Compounds (Hydrocarbons)
• are made of carbon and hydrogen. Examples: methane,
butane, propane, octane, etc.
• Natural sources: plant and animal emissions and
decomposition of organic matter.
• Anthropogenic sources: primarily combustion from
automobiles, trucks, buses, and other fossil fuel motors;
also evaporation of gasoline and other chemicals.
Major pollutants: (6) Photochemical Smog
• Ozone, NO2, formaldehyde and
other gases combine with solar
radiation to form Los Angelestype photochemical smog.
• Ozone causes respiratory and
heart problems.
• High levels of ozone result in
environmental degradation.
History of air pollution
(1) The medieval pollution
• In medieval London, pollution from coal
burning was seen as such a serious
matter that a commission was
established in 1285 to investigate the
problem. It was reconvened three years
later with firm instructions to find a
solution.
• In 1307, during the reign of Edward I,
legislation was introduced to prevent the
use of sea coal in kilns and by
blacksmiths. It proved largely ineffective.
History of air pollution
(2) The 16th – 19th century
• Wood for burning became scarce and
expensive, and an increasing number
of domestic chimneys encouraged an
ever-wider use of fossil fuel.
• London rapidly changed from a woodburning city to one that relied on
imported coal. By the end of Elizabeth
I's reign in 1603, coal consumption in
the city had risen to more than 50,000
tons a year.
• In 1661, the diarist and protoenvironmentalist John Evelyn
published a diatribe against air
pollution in London: Fumifugium, or
The Inconvenience of the Aer and the
Smoak of London Dissipated.
Image source
History of air pollution
(3) The Great Fog of 1952
• Lasted from Friday 5 to Tuesday 9
December 1952.
• A period of cold weather, combined with
an anticyclone and windless conditions,
trapped the pollution from Thames-side
power stations, domestic fires and
London's new fleet of 8,000 diesel
buses, which had just replaced the
battered but environmentally friendly
electric trams.
• The total number of fatalities was about
12,000.
• Led to several changes in practices and
regulations, including the Clean Air Act
1956.
Source
Video: Great London Smog 1952
• http://www.youtube.com/watch?v=rLN0lydEdr8
History of air pollution
(4) The 1948 Donora smog
• In October 1948, Donora, Pa., was
enveloped in a lethal haze.
• Over five days, nearly half of the
town's 14,000 residents
experienced severe respiratory and
cardiovascular problems. It was
difficult to breathe. The death toll
rose to nearly 40.
• Disturbing photos show Donora's
streets hidden under a thick blanket
of gray smog. A warm air pocket
had passed high above the town,
trapping cooler air below and
sealing in pollutants.
History of air pollution
(5) Air pollution in China
• Various forms of pollution have
increased as China has
industrialized, which has caused
widespread environmental and
health problems.
• According to the World Bank in
2007, 16 of the world's 20 most
polluted cities are in China.
Image Source
Pneumoconiosis in China
• 57,000 workers diagnosed
pneumoconiosis every year
• There are about 6 million
patients
• 6,000 workers die from the
condition every year.
Image source
Video: Beijing experiences terrible
air quality
• http://www.youtube.com/watch?v=Ksps_1
Zwg5o
History of air pollution
(6) Air pollution in India
• is a serious issue with the major
sources being fuelwood and biomass
burning, fuel adulteration, vehicle
emission and traffic congestion.
• The Air (Prevention and Control of
Pollution) Act was passed in 1981 to
regulate air pollution and there have
been some measurable
improvements.
• However, the 2012 Environmental
Performance Index ranked India as
having the poorest relative air quality
out of 132 countries.
Video: Science to Protect the Air We
Breath (by EPA)
• http://www.youtube.com/watch?v=3PO_3e
xwN-I
Air Quality Index
• The EPA created an index for air pollution monitoring called
the Air Quality Index (AQI).
• A formula applies to ozone, particulates, carbon monoxide,
sulfur dioxide, and nitrogen dioxide by expressing each
pollutant on a scale that ranges from 0 to 500.
• The official AQI for any location at a particular time is the
highest of the five individual pollutant values.
Air Quality Index
Environmental Performance Index (EPI)
• is a method of quantifying and numerically
benchmarking the environmental performance of
a country's policies.
• Developed by Yale Univ. and Columbia Univ.
• Recent reports in 2008, 2010 and 2012
2012 EPI
Summary
• Air pollution. 2 categories
• 6 types of major pollutants:
–
–
–
–
–
–
Particulates
Carbon oxides
Sulfur compounds
Nitrogen oxides
Volatile organic compounds
Photochemical smog
• History of air pollution:
–
–
–
–
–
The Medieval pollution
16th-19th centuries
Great London Smog 1952
The 1948 Donora smog
Air pollution in China and India
• Air quality index and Environmental Performance Index