Weather and Climate

1
Weather and Climate

• Lecture 2 May 2007
• Pollution

2
What kind of cloud?
3
What kind of cloud?
4
Air Pollution

• Not all pollution is anthropogenic (i.e.,
  man-made). Choking gases can also come from
  volcanoes and sea vents
• Air pollution effects are magnified when areas
• have light winds (little or no horizontal mixing)
• under inversions (little or no vertical mixing)

What kind of feature has light winds and
inversions?
5
Smog

• Term coined by London physician Harold Des Voeux
  in 1911 -- a combination fog and smoke.

6
The solution to pollution is dilution
That is, the short-term solution to an immediate
problem
7
There are some very famous pollution episodes

• Donora, Pennsylvania in October 1948
• London, England in December 1952

8
Donora, Pennsylvania

• Inversion under a High Pressure System (warm air
  aloft, little vertical mixing)
• Weak horizontal winds associated with High
  pressure

9
Donora Pennsylvania
H
Donora is in a valley along the Monongahela River
southeast of Pittsburgh
10
Donora, PennsylvaniaOctober 1948

• That smoke puts bread on my table
• Killed about 20 people (primarily those with
  pre-existing respiratory problems)
• American Steel and Wire Company
• Donora Zinc Works -- zinc and iron works
• Lots of Sulfur Dioxide emissions mixed with fog
  to yield sulfuric acid fog
• Persisted Friday-Sunday, then it rained
• Conspiracy theorists killed by flouride

11
Why not in Pittsburgh?

• Just started cutting back using bituminous coal
  as a power source for Steel works
• Just started a smoke control ordinance
• Walter Winchell reported from Donora, and it
  gained national infamy
• Donora (and others) lead to Clear Air Act (1970)

12
Whats the difference between smog in Donora in
1948 and in LA of Houston today?

• Smog in Donora a mix of fog and SO2 -- led to
  sulfuric acid mist (ouch!)
• Smog today -- ozone, Nitrogen oxides, volatile
  compounds
• Today smog causes different types of health
  problems

13
Fog in 1952
Light surface winds, an inversion aloft
14
London in December 1952

• Spell of cold weather -- lots of coal burned for
  heat -- lots of dirty smoke
• Inversion developed at night on the 5th/6th
• Visibility lt50 m for more than 2 days!
• Thousands of tons of black soot and sulfur
  dioxide particles from coal burnt for heat
• weight of smoke (mg/m3) increased 5-10x
• SO2 concentration increased up to 10 fold

15
(No Transcript)
16
London England 1952
From a book Peoplefound their way along the
sidewalks by feeling the walls of buildings
17
What was in smog?

• 1000 tons of smoke particles
• 2000 tons of Carbon Dioxide
• 140 tons of hydrochloric acid
• 14 tons of flourine
• 370 tons of sulfur dioxide converted to 800 tons
  of sulfuric acid

18
How did Fog kill?

• Bronchitis/asthma suffers suffocated as they
  wheeze to death
• Congestive heart failure -- lack of oxygen makes
  heart work harder -- leads to cardiac arrest
• ozone causes permanent lung damage -- other
  contaminants damage respiratory cells, cause lung
  inflammation
• Week before 2000 died.
• Week of fog 4000 died

19
Fog as a Killer
Death rates rose most for 45-64 year-olds 2/3rd
s of those who died were gt 65.
20
When did the Fog lift?

• 10 December -- after 5 days -- winds shifted to
  west and blew the fog out down the Thames and out
  to sea.
• Probably more vertical mixing as the weather
  regime shifted, so pollutants moved higher into
  the atmosphere as well
• During the episode, pollutants were confined to
  the boundary layer

21
Other famous pollution problems
Houston, Texas
Causes Automobiles, Petrochemical
plants Aggravations Sea breeze/land breeze
circulation Stagnant weather for much of summer
-- no change in airmass
22
Houston pollution from satellite
Convert difference in downward looks and fore/aft
looks to particulate density (optical depth)
23
Denvers Brown Cloud
Sources Automobiles, wood-burning stoves big
improvements since early 1980s
Periodic inversions trap air below mountain tops
24
Los Angeles

• Sited in a basin
• Downstream of Pacific High (downward motion, and
  an inversion)
• Difficult to ventilate -- pollutants get trapped
  in sea/land breeze circulation
• Lots of cars!

25
Mexico City
7500 above sea level
24,000,000 people
View From Space Shuttle
26
Beijing
New Delhi
The persistent haze is a pungent mixture of
wood, coal, and cow-dung smoke, with generous
contributions from diesel auto, bus, and truck
exhaust, and from the ubiquitous gas/oil-burning
scooters and rickshaws
27
Why do inversions promote pollution?
28
Pollution distribution in vertical controlled by
the stability
Difficult for particles to move in the vertical
Particles easily move in the vertical
Particles easily move to the surface, but dont
move aloft
29
Pollution Mitigation

• Make smoke stacks very tall!
• Stack output into inversion layer, above the
  unstable boundary layer
• Site smokestack in a region where drainage winds
  will remove pollution -- or where youre far from
  population
• Put your powerplants somewhere besides downtown!

30
Other effects of pollution

• Adds cloud condensation nuclei to air
• Fox River Valley cloudiness from extra CCN from
  paper plants (more fog?) -- ditto Tyrone PA in
  the 1960s
• Heat source at smokestack, so cumulus cloud at
  the top of smoke plume
• If you live on a lake, pollutants can get trapped
  in Lake Breeze and never ventilate.

31
Main pollution sources

• Mercury and sulfur from coal-burning power
  plants
• Smoke from forest fires can cause pollution over
  very large areas
• Carbon Monoxide, Nitrous Oxides from vehicles

32
Alaska had many fires in 2004
33
Visible from space
34
In the infrared channels too!
Dark Pixels are very warm (fire)
35
Acid Rain

• Acid Rain is mostly caused by SO2 and NOx
• 2/3 of SO2 from coal-fired power plants
• 1/4 of NOx from coal-fired power plants
• Pure rainwater has pH of 5.5
• pure water pH of 7
• Acid rain pH of 4.3
• pH down to 2.5 observed (Mt Tsukuba, 1984)

36
(No Transcript)
37
Effects of Acid Rain

• Increased mortality in aquatic specieschart at
  right shows that some are more tolerant of acid
  than others
• Effects tempered by local geography, especially
  limestone

38
Effects of Acid Rain

• Increased nitrogen deposition in water leads to
  algal blooms
• Damages leaves, and weakens trees
• Weakens paint on cars
• Erodes marble in buildings

39
More on Acid Rain
Trees die from the top down (spruce, sugar maple )
Deforestation in Germany 1970 and 1985 images
40
Acid Rain weakens and then something else kills
the tree

• Ice Storm
• Persistent drought
• Too much water

41
Pollution Modeling

• Use numerical models to tell where the pollutants
  from a stack will end up
• Employs many meteorologists!
• Fundamentals of Stack Gas Dispersion
• buoyant smoke plume rise
• Gaussian modeling theory
• Local meteorological observations
• very realistic topography
• interaction between microscale and mesoscale