introduction to energy & environment - uw oceanography€¦ · tendrils of bright red lengthen;...
TRANSCRIPT
Lecture 9-10 HAS222d-09
Introduction to energy & environment Air pollution
applying flux and concentration ideas to pollution and to basic atmosphere/ocean dynamics
•
The chapter in Spherical Cow on ‘steady state box models’ assumes simple, well-mixed reservoir with volume M with steady flow F in and out, giving a residence time M/F
for water or whatever the flowing material is. One can work in terms of volume or mass, using the density ρ
(kg/m3) to convert from one to the other.
Then if a pollutant is poured in upstream with a known rate (kg per second) the ultimate steady-state concentration of the pollutant in the reservoir can be calculated.
–
This model needs much improvement however:•
the flow or the pollutant injection may vary with time•
the reservoir may not be ‘well-mixed’ (as in smoke in the atmosphere)•
indeed the reservoir may not even be well-defined (as in the stratified global atmosphere ,where the pollutant never fills the whole region
•
the flux of pollutant or other trace substance (e.g.water
vapor) is expressed as a concentration C times a flux of mass of fluid:
mass flux = ρVA (kg/m3)(m/sec)(m2) …= kg/secwhere A is the cross-sectional area of the flow and V the velocity.
flux of pollutant or tracer = C ρVA where C is given as kg of tracer per kg of solution (water + tracer).
STIRRING AND MIXING: often a trace substance or pollutant is distributed complexly in a fluid. How does it become diluted in concentration? Think
of a red-colored pollutant. Since chemical reactions and molecular diffusion and heat flow occur where surfaces touch, the area of contact between the red fluid and clear fluid
is crucial. This is how we mix cake mixes…stirring and stirring until we have stretched out
the ‘red’ part enough for chemical reaction to occur along the edges of the red component.
In the same fashion, chaotic fluid flow stirs a pollutant (a ‘tracer’),stretching
it out until if finally ‘mixes’ by molecular diffusion. Tendrils of bright red lengthen; their surface area increases; finally all is uniformly pink.
The figures show a dye tracer being stirred in a fluid…while it is still a chaos of thin red curves before it has mixed to ‘pink’.
The biosphere as seen with satellite images of color (here ‘false color’ recoded to bring out detail). Chlorophyll of primary production of vegetable matter (‘grass of the
seas’) in ocean; snow-cover, forests, deserts on land and ‘blue deserts’ in ocean.
note the bands of wet and dry land..from
rain forests to deserts,which are tied to the cycling of fresh water evaporated from the
oceans
phytoplankton at the surface of the Mediterranean Sea
(false color SeaWiFS
satellite image) showing complex tendrils due to stirring by ocean currents. Biological communities have to adapt to this chaotic stirred environment: a complex place to raise a family!
water vapor in the middle levels of the troposphere, showing very long streaky
features extended by storm-like cyclonic weather systems.
MORTALITY:WHO
figures show an estimated 2.4M (million)
people die each year because of
air
pollution. This health impact represents about 4.3% percent of the total 56M deaths that occur annually in the world.
Indoor air pollution is found to cause 1.6M of these deaths
Smoking is not included in these numbers: smoking is estimated to cause 4.83M deaths per year from The Lancet, 2003 (primary, not secondary smoke).
The reliability of these numbers must be investigated, yet public health studies are now based on huge populations (which helps make reliable statistics). The numbers are so big than the dangerous effects of even individual pollutants can sometimes be found out.
news item: Environment Pollution May Cause 40 Percent of Global Deaths
By
Andrea Thompson, LiveScience
Staff Writer
posted: 10 September 2007 09:11 am ET
Buzz up!
•
Water, air and soil pollution, along with other environmental factors, contribute to 40 percent of deaths worldwide each year, a new study concludes.
•
In a review of research into the effects of
environmental pollutants
and other sources of environmental degradation, Cornell University ecologist David
Pimentel estimates ???that 62 million
deaths per year (40 percent of all that occur)??? can be attributed to environmental factors, particularly organic and chemical pollutants that accumulate in the air we breathe and the water we drink.
•
Though scientists and organizations such as the United Nations and the World Health Organization have begun keeping tabs on the role environmental pollution plays and were aware of the enormous impact that some pollutants have, "we
were surprised with the number," Pimentel said.
•
This "suggests the importance of the environment as it's related
to our deaths," he toldLiveScience.
•
note: most estimates put death rate at 56M per year, ca. 2003 (e.g. Wikipedia http://en.wikipedia.org/wiki/World_population ) PR 30.iv.09
http://www.livescience.com/environment/070910_pollution_deaths.html
The US EPA (Environmental Protection Agency) has set quality standards for 6 air pollutants, following the Clean Air Act created during
the Nixon administration.
carbon monoxide,ozone,lead,
nitrogen dioxide,particulate matter (also known as particle pollution)
sulfur dioxide
NOTE CO2 recently added!!!www.epa.gov/airtrends
•
However there are many more air pollutants of note:
–
nuclear debris (radioactivity from nuclear plants: e.g. Chernobyl–
naturally radioactive radon gas (in basements of houses)–
VOCs
(volatile organic compounds) of many kinds, for example in ‘scented household products’ There is a sad history where volatile compounds are developed and used widely, before finding that they are toxic. An example is pentachlorophenol, or ‘penta-preservative’ which is painted on exterior wood as a preservative. If you Google it, you will find industry
websites proclaiming it to be harmless to health and other sites describing serious efffects
of inhaling the vapors. I used to use it; an hours work would leave me dizzy. Professional painters continue to use it every day with anecdotal signs of serious health effects. Chemical sensitivity can change if you are exposed to toxic fumes: it is possible to end up unable to tolerate ‘normal’ smells, requiring the use of an air-filtering mask. It seems that government regulatory agencies have difficulty keeping up with the thousands of VOCs
now present in the human environment, each of which would require lengthy health studies, in order to develop regulations for their use.; Pentachlorophenol is ‘suspected of causing reproductive defects and cancer on the basis of animal studies’. (Marer & Grimes, Wood Preservation in Univ. of California statewide integrated pest management project, publication 3335) Ironically the university study finds that a non-toxic alternaive
made of paraffin wax, varnish and mineral spirits is equally effective at preserving outdoor wood surfaces.
–
formaldehyde derived from methyl alcohol, in carpets, wood sheathing of houses, walls of FEMA
modular homes set up for Katrina hurricane victims
…beware of ‘new carpet smell’–
asbestos in old ceiling tiles, insulation –
other fire retardants in clothing–
biological spores, pollens related to human allergies
•
particles: smoke, car exhaust, metal chips, blowing soils (e.g. Asian loess, Saharan red sand), important down to the scale of 0.1 micron, where they are invisible and float permanently in the air.
•
"Coal is the single greatest threat to civilization and all life on our planet." –
James Hansen, NASA's top climate scientist
•
Dirty air, acid rain and contaminated land and water. Health problems associated with coal pollution include childhood asthma, birth defects and respiratory diseases that take nearly 25,000 lives each year in the US.
•
mountaintop removal http://www.nrdc.org/energy/coal/mtr/default.asp
http://www.rainforests.net/graystreaks.jpg
burning of Amazonia
to grow crops…for a few short years.
earthobservatory.nasa.gov/NaturalHazards/
more burning in South America (fire sites shown)
http://news.mongabay.com/2005/0906-nasa_africa_fires.html
Jan 2005 May July
1 km resolution images: seasonal change in location of fires in Africa
vertical structure of smoke layers from California Santa Anna fires 28 Oct 2003 thin layers of smoke/dust can cross entire oceans and then rain out: they are not well-mixed through the depth of the atmosphere!
•
visibleearth.nasa.gov/view_rec.php?id=16620
summer fires in the US northwest: increasing in frequency and acres burned, subjecting many people to smoke
smoke particles smaller than 1 micron (10-6m) linger in the air for long times and get deep into the lungs. Combustion (cars, factories, power plants) are not the only sources. Agriculture puts fine particles into the air, some smaller than
the measured particle sizes; so the countryside is not completely ‘clean’.
we know precisely how fast heavy particles fall through still air….which tells us that below about 1 micron (10-6m) particles almost ‘don’t fall out’
Note here the ‘pulmonary region’ refers to the deeper lung passages.The clearing of soot from the lung is carried out by viscous fluid whichslowly flows; yet the narrow passages where much of the oxygen transferoccurs are too small for this fluid cleaning mechanism to work. It is thesmallest particles that can reach these regions, where they can remain for life and destroy lungfunction. From Chemistry of the Upper and Lower Atmosphere, Finlayson-Pitts and Pitts,Academic Press, 2000
Small particles get deep into our lungs:
•
The human nose is remarkably able to sense small concentrations of chemically active particles/gases…fragrances (but animals are
vastly more able to, for example, smell a human being hundreds of meters away). However, are sense of smell is easily dulled. This works against us, allowing us to live in smoky environments… ’getting used to it’. Research into pheromones (the science of
chemical production of smell by animals) is exciting, as it relates to remarkable abilities of animals to hunt prey, migrate and navigate, as well as relating to ‘relationships’.
An experiment: next time you leave the city for more than a day in the country see if you can smell individual cars as they drive by..I
have noticed this particularly in dry air, e.g. in the Colorado mountains.
one of the most abundant potential energy sources is coal, particularly in the US. Yet it comes at a steep environmental price all the way from damaging mining practices to sooty
air, to global warming
http://www.nrdc.org/energy/coal/mtr/default.asp
coal sources: mountain-topping in Appalachia
on average, our air is getting cleaner. PM10
is the measure of particles of size about 10 microns. This average result is in part due to dilution of intensely polluted source air
(which you would not expect to affect the ‘average PM10’ yet it seems to. There remain intensely polluted regions…’hot-spots’
PM 10 concentrations US and UK;cost (?) of smoke in US ($ per person)
Indoor air seems to be one of the ‘hot spots’ of pollution. It is not clear why, but
asthma occurrence is increasing with time (indoor air pollution; life-style changes, with more time spent indoors?)
Indoor air pollution is thought to cause about ½ of the air pollution illness &
mortality, roughly 1.6M deaths per year globally.
note logarithmic scale, it’s worsethan it appears at first sight
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Air pollution attributable postneonatal
infant mortality in U.S. metropolitan areas: a risk assessment study
•
Reinhard
Kaiser1 , Isabelle Romieu2 , Sylvia Medina3 , Joel Schwartz4 , Michal
Krzyzanowski5
and
Nino Künzli1,6
•
Results•
The estimated proportion of all cause mortality, sudden infant death syndrome (normal birth weight infants only) and respiratory disease mortality (normal birth weight) attributable to PM10
above a chosen reference value of 12.0
μg/m3
PM10
was 6% (95% confidence interval 3–11%), 16% (95% confidence interval 9–23%) and 24% (95% confidence interval 7–44%), respectively.
•
Environmental Health journal
•
Spatial distribution: going beyond ‘average’ pollution and averages of other measures of the environment: the connection with industrial production, ‘intensity’ of the global economy
The world is not flat: energy use (via the Earth at Night lighting proxy)
(R.Florida, Atlantic Monthly Oct. 2005) Note that since 2005 it is likely that the energy use in China has risen noticeably relative to this map, as they have come to dominate the production of many commodities. China has recently surpassed the US in carbon emissions, and is close in total energy use (though at a rate only roughly 15% of US in energy use per person). Wikipedia
lists China at 1.5 kW
per person, US at 10.4 kW
per person, for the 24/7 use of marketable energy. In terms of
total rate of energy use, US is still ahead at 1. x 1020
J/year versus China at 0.63 x 1020
J/year 2004, source Wikipedia) Apparently China’s use of more coal puts them ahead in carbon emissions
http://en.wikipedia.org/wiki/List_of_countries_by_energy_consumption_per_capita (2004, source Wikipedia)
http://en.wikipedia.org/wiki/List_of_countries_by_energy_consumption_per_capita
The world at night: lighting correlates surprisingly well with industrial output; after correcting for ‘technology’ it also relates to the distribution of particle pollution, SO2
and NOx
oxides of nitrogen.This
image can be used to estimate global distribution of industrial
activity, energy use and also ‘prosperity’ You can see major cities and highways in this light map
NO2
nitrogen dioxideseen by satellitespectrometer European SpaceAgency
Akimoto, Science 2003
units: 105
molecules per cm2
SO2
here is an example of the ‘geography’ of pollution.Asia is worsening while Europe improves (above)
http://www.esa.int/esaCP/GGGDV4TZ0GC_index_1.html
ozone...here the lower atmospheric ‘bad’ ozone which is produced when the sun shines on nitrogen oxides pollution (often car exhaust).
Akimoto, Science, 2003 These figures compare the
pre-industrial world (modelled)
with present conditions
Some overall statistics of air pollution (plots from The Skeptical Environmentalist, by Bjorn Lomborg). Here smoke and SO2
(sulfer
dioxide) average concentrations estimated from 1600 to 2000
OZONE (O3
) left and nitrogen dioxide (NO2
) The daily cycle of ozone production by sun shining on oxides of nitrogen shows their out-of-step behavior in time (through 2 days)
The map below shows the eastern USdeveloped corridor is a concentration ofozone.
lower-atmosphere ozone
GOOD ozone: in thestratosphere, our shield against destructive UVBradiation (~ 300 nanometerwavelength compared with visible light at 500 nanometers)
further signs of improvement: US average NO2
concentration declining with time (1980-2007). Source: US Environmental Protection Agency
right: Seattle region
http://epa.gov/airtrends/nitrogen.html
Oxides of nitrogen: sources
From WIkipedia: Oxides of NitrogenThis section refers to the chemical term for nitrogen oxides produced during combustion. For other definitions see NoxThe term
nitrogen oxide
typically refers to any
binary compound
of
oxygen
and
nitrogen,or to a mixture of such compounds:
•Nitric oxide
(NO), nitrogen(II) oxide•Nitrogen dioxide
(NO2
), nitrogen(IV) oxide•Nitrous oxide
(N2
O), nitrogen (I) oxide•Dinitrogen
trioxide
(N2
O3
), nitrogen(II,IV) oxide•Dinitrogen
tetroxide
(N2
O4
), nitrogen(IV) oxide•Dinitrogen
pentoxide
(N2
O5
), nitrogen(V) oxide(Note that the last three are unstable.)Chemical reactions
that produce nitrogen oxides often produce several different compounds,the proportions of which depend on the specific reaction and conditions. For this reason, secondary[clarification needed]
production of N2
O
is undesirable, as NO and NO2
— which are extremely toxic —
are liable to be produced as well.
Nitric oxide, NO Nitrogen dioxide, NO2
Nitrous oxide, N2ODinitrogen
trioxide, N2O3
Dinitrogen
tetroxide, N2O4
Dinitrogen
pentoxide, N2O5
sulfur dioxide…from coal fired power plants
lead……thanks Mr. Midgely
www.epa.gov/airtrendsl
US air quality 1990 -
2007
1980 vs 2007
1990 vs 2007
CO -76 -67
O3 (8-hr) -21 -9
Pb -94 -80
NO2 -43 -35
PM10 (24-hr) --- -28
PM2.5 (annual) --- -11
PM2.5 (24-hr) --- -9
SO2 -68 -54
percent change in US emissions 1980-1990-2007 www.epa.gov/airtrends
1980 vs 2007
1990 vs 2007
CO -55 -44
Pb -97 -72
NOx -39 -33
VOC -50 -35
Direct PM10 -65 -33
Direct PM2.5 --- -51
SO2 -49 -45
www.eps.gov/airtrends: US only. Of key importance of course is not
just the US average but the ‘hot spots’ of pollution which are numerous. Here more than ½ the US population lives with some form of excess
pollution (in excess of federal health standards). And recall that the US EPA only regulates a few pollutants.
•
Solutions…Our parents and grandparents generally ingested vastly more pollutants than we do…but it’s a moving target. VOCs (volatile organic compounds, heavy metals, smoke particles…are still with us but less visible, and their impact not yet understood. –
prosperity (but not too much)–
monitoring–
epidemiological studies: quantitative connections between pollution and health
–
remediation: capping emissions, changing energy modes, improved
cures for pulmonary disease and cancer
–
new technologies to clean the air and the deposition sites–
simple technologies to clean household air (responsible for ½ the human fatalities)
•
coaxial air exchangers bring in clean outdoor air, jet out the bad indoor air, yet retain heat and moisture indoors
•
solar box cookers in sunny developing countries instead of burning wood for cooking, water purification
•
electrostatic air cleaners in homes–
activism: extreme pollution sources go unnoticed for long periods of time,and
the danger thresholds are constantly being revised…–
global consensus to drown out short-term economic thinking–
banning of pollution ‘export’ •
loess from China•
smoke from Africa, South America, SE Asia•
SO2
from US, Europe, Asia–
special efforts for developing world…the early rising pollution curve,
•
Finally, this is all human centered (as McNeill admits in his book). What about the global ecosystem and the impact of air pollution on plants and animals? A complex, multi-dimensional set of issues!
•
Notice, though Nature’s resilience: why are leaves so clean?
tree leaf 400 micron image
water on a tulip
for example: solar cooking and water purification
In India, where a reported 90 percent of cooking is done over wood-
and dung-fueled fires, several studies have documented that “indoor air pollution leads to 400,000-550,000 premature deaths … from lower respiratory infections and chronic obstructive pulmonary disease. … The burden falls disproportionately on women and children, who inhale soot and other particles from smoke released by the burning of biofuels.” This soot combines with outdoor air pollution to form atmospheric brown clouds (ABCs) that “envelope most of India and the Indian Ocean … [leading] to a large reduction of sunlight at the ground and … atmospheric solar heating
India is well-known for delicious food, and the kitchen is considered to be a sacred place in any Indian home. And now India has something else to be
proud of: the world’s largest solar kitchen. The system has been installed as a collaboration between the
Academy for a Better World
and
Brahma Kumaris
World Spiritual University, with technology from
Solare-Brücke, Germany. With 84 receivers and cooking at 650 degrees, the system can produce up to 38,500 meals a day when the sun is at its peak!
The system generates temperatures of up to about 650 degrees, and 3500-4000 kg of steam per day. The food is cooked in 200-400 liters capacity cooking pots, producing an average of 20,000 meals a day, and up to 38,500 meals per day
during periods of peak solar radiation maximum.A total of $5 million has been spent on this endeavor.
the pollution-prosperity curve:as a society progresses it develops industry, increasespollution as well as wealth. Then,predictably, the society decidesto clean up its nest and airquality improves.
air quality measuring stations…western Washington. Sustained observations (‘time-series’) are keys to understanding pollutantbehavior…and to deciding where you want to live!
Clearing the Air: US EPA2002 SO2 . NOx
The process of seeking a cleaner environment involves many challenges; one idea is ‘biomimicry’, in which we imitate Nature in our buildings, fuels and
materials. This is discussed in the book Natural Capitalism.
Costa Rica: Rancho Mastetal. The hooch was designed and built by last year’s course and finished by volunteers. The instructors stayed there this year. Structural bamboo is a sustainable crop in Latin
America, and makes a fine house.