Download Statistics and Air Pollution

Statistics and Air Pollution
Prof. Montserrat Fuentes
Statistics Department NCSU
Member of the EPA Science Advisory board,
and the National Academies panel studying
link of ozone and mortality.
What is Statistics?
According to the ASA: “Statistics is the science of collection,
analysis, and presentation of data. Statisticians use data
to solve problems in a wide variety of fields.”
The Miriam-Webster Dictionary uses a subtlety different
definition: a branch of mathematics dealing with the
collection, analysis, interpretation, and presentation of
masses of numerical data.
All these definitions reflect our strong disciplinary roots in
handling data in real world applications
The Rise of Statistics as a
Discipline
• In Europe, the history of statistics goes back to the1600s
• But things were a bit slower in the US …
• What is a discipline? Per the Council of Graduate
Schools:
Established a theory and body of literature
Significant number of professionals working in the field
Several regularly published professional journals
• US Statistics had met these criteria by the end of World
War II
Key influences
• Key influence –The Great Depression
Statistics was one subject that expanded (Joseph Doob)
• Key influence –World War II
Control charts
Acceptance sampling
Theory of games
Decision theory
Immigration of European statisticians
Post-war industry and development
More opportunities for women and minorities
• Key influence –Agriculture
1839 –ASA founded
1888 –beginning of JASA
1918 –Dept of Biometry & Vital Statistics, JHU, Raymond Pearl
1930 –beginning of Annals of Math Stat
1933 –Iowa State’s Statistical Lab, George Snedecor; dept in
1947
• 1935 –Dept of Statistics at George Washington Univ, Frank
Weida
• 1935 –IMS organized
• 1938 –UC Berkeley’s Statistical Lab, Jerzy Neyman, dept in 1955
• 1941 –NC State’s Department of Statistics,
Gertrude Cox
• 1945 –beginning of Biometrics
• 1946 –UNC Dept of Math Stat, Gertrude Cox & Harold Hotelling
• 1947 –Biometric Society founded, Gertrude Cox
• 1947 –beginning of American Statistician
• 1949 –UNC Dept of Biost, Gertrude Cox & Bernard Greenburg
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Dramatic increases in computing power, decreasing
costs. Typical applied scientist now has massive
computational power available at his/her desk
Early portable computers 100 times as heavy,
500 times as large, 10 times as much, 100
times slower than an iphone
In a Statistical Science interview with
Brad Efron, Rob Tibshirani (Stanford)
says:
“One of the challenges I've found is that we're a funny field
in a sense that lots of other people who aren't
statisticians do statistics. We don't do chemistry or
biology; we don't go into a lab and start filling up test
tubes. Statistics is something you can do if you have a
personal computer. So, it's a challenge in the sense
that a lot of people think they can do it well, but
aren't. We not only have to do good statistics, but also
spread the word to other sciences about the right way to
do things”
New science, new data capture
Square Kilometre Array --- the world’s most powerful
radio telescope will generate more data in one day than
the total data on the internet today
The SKA will
– Have the processing power of about 1 billion PCs
– Involve enough optical fibre to wrap twice around the earth
– Generate enough raw data to fill 15 million 64 GB iPods every day!
Standard methods will not work! Methods need to scale
up
The data explosion
Current
e - research
focus
Data
capture
Data
management
Critical
Gap –
standard
methods
inadequate
Data analysis,
data fusion,
visualization
Great opportunity!
But we must grab it!
Need
interdisciplinary
team including
ICT, statistics,
subject matter
expertise
Policy/impact
Some grand challenge problems:
• Climate
How will rainfall change in 50 years?
• Weather
How predictable is the weather tomorrow?
• Chemistry
How do human activities effect air quality?
• Strategic applications
How will a toxic agent disperse?
• Environmental Health
Does the air we breath kill?
Combine using Statistical methods complex numerical
models with a variety of observations
Nelson’s Column during the
Great Smog of 1952, and today
Does the Air We Breath Kill?
Scientific and Statistical Issues
Siource: Scott Zeger
Source: Scott Zeger
Health impacts of the London
smog of 1952
In the winter of 1952 one of the worst air
pollution episodes on record took place
in London. While it had long been known
that air pollution can affect health, this
event along with other extreme episodes
catalyzed modern-day research of
pollution and health as well as air
pollution control regulations.
Air pollution affects people
• EPA estimates 10,000 pollution deaths per
year.
• Smoking: 400,000 smoking deaths per year.
Laws for clean air
These laws are called the 'Clean Air Acts'.
WHAT ARE THOSE BAD AIR POLLUTANTS?
Ozone and particulate matter.
Ozone can be good or
bad. It all depends on
where it is.
Ozone is good when it
is high up in our
atmosphere. It
protects us from
sunburn.
Ozone is bad when it
is near the ground
where we can breathe
it in.
We can't see ozone in the air. Bad ozone is sometimes called
smog. It is formed when chemicals coming out of cars and
factories are cooked by the hot sun. Ozone is more of a problem
in the summer.
It is not healthy to
breathe harmful
ozone, in fact, bad
ozone can burn our
lungs – just like sun
can burn our skin.
Other symptoms
include coughing,
wheezing, chest pain
and headaches.
Laws for air pollution.
We have laws to keep our air clean.
The Environmental Protection Agency tries to
make sure the ozone does not go “too high”.
Have you ever noticed a sunbeam with lots of little specks of dust
floating in it?
That is particulate matter. Some particles are so small that we can't even
see them - these are the ones that can penetrate deep into our lungs.
Particulate matter is mostly dust and soot so small that it floats in the
air. These particles come from anything being burned.
Trucks and tractors, power plants, and wood-burning stoves make a lot of
these small particles.
Hourly AQI
How is the air
Quality in our nation?
How is the air quality in our nation?
Ozone
Particulate matter
Mecklenburg
County , NC
Statistical challenges in
quantifying “risk”
Statistical tools for the analysis of Mortality
related to air pollution and temperature.
Effect of high levels of particulates (PM10) on short
term, nonaccidental mortality rates.
Statistical model for risk
assessment
Risk of mortality due to PM10
How to estimate the economic
benefits associated to new
standards
After estimating the reduction in individuals’ risk of
premature death stemming from the proposed
change, the number of premature deaths avoided
due to the postulated reduction in ozone
concentrations for the population at risk is
obtained.
A central estimate of the economic value of these
avoided deaths is then calculated using a central
Value of Statistical Life (VSL) drawn from the
available literature.
“Value of statistical life”: to determine the
benefits of air quality regulation
 1. Assume that each person in a group of 10,000 is
willing to pay $500 for a policy that reduces the risk
of dying in the next year from 5 per 10,000 to 4 per
10,000.
 2. There will be one less death in this group if the
policy is undertaken. But we can not know which of
the 9,996 survivors would have died in without the
policy.
 3. The group had an aggregate willingness to pay of
$5 million ($500 x 10,000) and one death was
avoided.
 4.The value of this statistical life is $5 million
 The administrator, Stephen L. Johnson, said that by law he was
forbidden to consider costs in setting the standard, but urged Congress
to change the law so future administrators could do just that. (New
York times)
 In defining the cost of implementing new
standards, the economic benefits (using
VSL) should be also taken into
consideration.
Related issue: The impact of climate
change on ozone and human health
 Changes in ambient ozone levels are one of
the many ways in which climate change
could affect human health. Our ongoing
work investigates how climate change could
alter ozone concentrations in the U.S. and
the subsequent impacts on human health.
Reich, Fuentes and Dunson (2009)
Impact of climate change on air
pollution regulation.
Due to the strong dependence on weather
conditions. Ozone levels may be sensitive to
climate change.
Using future numerical climate models, we
could forecast potential future increases or
decreases in ozone levels.
Statistical models for forecasting air pollution.
Projected Summer Ozone Levels (2050’s vs. 1990’s)
Probabilities that the 3 year (2003-2005 left graph; and 20412043 right) average of the fourth highest daily max. 8-hour
average ozone exceeds 75 ppb.
Reich, Fuentes and Dunson
(2009). Bayesian spatial quantile
regression.
We can achieve the dream ....
(Presentation by Hal Varian - Chief Economist, Google, to the
2008 Almaden Institute, Innovating with Information.
"... with data in huge supply and statisticians in short supply,
being a statistician has to be 'the really sexy job for the
2010s'.)
Statistics- potential for a new age
This is our year!
2013 International Year of STATISTICS
Thank you!