jessica weber spring 2008 updated from dan gloudemans, spring 2005
TRANSCRIPT
Jessica WeberSpring 2008
Updated from Dan Gloudemans, Spring 2005
VOC’s Ozone
Formation, natural/other VOC’s
Destruction, natural/other CFC’s
Measurement / EPA AQI Ozone hole Phenomenon What is being done about Ozone?
OTC CARB
Recent News Fun Facts Questions
Organic Compound – contains carbon and hydrogen Ie: octane, butane…, sugar
VOC = Volatile Organic Compound, organics that evaporate easily
VOC’s are compounds that lead to the formation of ground level Ozone – “smog”
VOC’s can be found in anything from paints to deodorant
Ozone is beneficial in Stratosphere blocks many ultra violet rays (λ < 320 nm) 90% of ozone is found here
Ozone is harmful in Troposphere it is a highly reactive gas that can affect the normal
functioning of the lungs Thickness of the ozone varies seasonally and
geographically Greatest concentrations are between 15 and 40 km,
ranging from 2-8 ppm Found during the spring in mid-to-high latitudes
Lowest concentration is found during Sept –Oct over Antarctica (ozone hole phenomenon)
Ozone first formed - ~500 million years ago Ozone formation – atomic Oxygen
O3 is unstable, creates ozone-oxygen cycle
Most natural ozone formation occurs in the Tropics
“Chapman reactions” So called after S. Chapman who is famous for his paper 'A theory of upper-atmosphere ozone, Mem. Roy. Meteorol. Soc.' in 1930 which set out the first theoretical explanation of the ozone layer in the stratosphere.
Photochemical reaction of NOx (Nitrogen oxides: collectively NO and NO2) with peroxy radicals in the presence of sunlight
HO2 + NO → OH + NO2 NO2 + hν → NO + O O + O2 → O3
Results in commonly known “Summertime Air Pollutant”
Sources of Nox Motor vehicles, Industrial Commercial Residential Fuel
Combustion, Utilities Sources of VOC
Industrial Commercial Processes, Motor Vehicles, Consumer Solvents
VOC production (2004)
Ozone destruction by UV radiation Ozone dissociates by absorbing a UV proton with λ<240
nm, photolysis
O + O3 → 2 O2 Large volcanic eruptions can affect ozone levels
Increases stratospheric chlorine concentrations by producing aerosols
Free radical catalysts (NO, OH, Cl, Br) Causing ozone levels in the northern hemisphere to
drop approximately 4% per decade. CFC (choloroflurocarbon) compoundsPhotodissociation of CFCs
Contain chlorine and bromine radicals CFCl3 + hν → CFCl2 + Cl
Once separate from parent compound can react with ozone
Cl + O3 → ClO + O2
ClO + O → Cl + O2
A single Cl atom can continuously destroy ozone for 2 years
Destruction allows more UV radiation through at harmful wavelengths causing increased genetic damage to living creatures and organisms.
Fortunately, where DNA is easily damaged, such as by wavelengths shorter than 290 nm, ozone strongly absorbs UV.
At the longer wavelengths where ozone absorbs weakly, DNA damage is less likely. If there were a 10% decrease in ozone, the amount of
DNA damaging UV radiaton increases by about 22%. DNA damage can most commonly lead to skin cancer
Increased UV radiation is expected to affect crop yields UV rays kill cyanobacteria on roots of rice plants
Reported in Dobson Units (DU) G.M.B. Dobson
developed a spectrophotometer that was used to measure stratospheric ozone
Measure concentration of ozone in a column
1 DU = 0.01 mm of Ozone
300 DU a typical value Thus, 300 DU = 3 mm
O3 spread evenly across earth
Measures presence of 5 pollutants
ground-level ozone
particle pollution carbon monoxide sulfur dioxide nitrogen dioxide
0-500 Scale 100 is National Air
quality standard ~200 – unhealthy -
whole population could be affected
>300 - Hazardous
Over Antarctica First discovered/measured in 1985 by
the British Antarctic Survey TOMS (Total Ozone Mapping
Spectrometer) During the winter season, a vortex of
winds develops around the pole and isolates the polar stratosphere
As temperatures drop below -78°C (-109°F), thin clouds form of ice, nitric acid, and sulphuric acid
Chemical reactions on the surfaces of ice crystals in the clouds release active forms of CFCs
2006 2007
US adopted Montreal Protocol in 1987 – limit CFCs States most dangerous CFCs phased out by
2000 With compliance of the Montreal Protocol;
the ozone layer is expected to begin to recover in coming decades due to declining ozone-depleting substance concentrations (2005 article) In 2006, the ozone layer saw the worst level of
depletion in recorded ozone history.
Clean Air Act (1963) All class I substances outlawed by Jan 1 2000
chlorofluorocarbon-11 (CFC–11) chlorofluorocarbon-12 (CFC–12) + others
All class II substances outlawed by Jan 1 2030 hydrochlorofluorocarbon-21 + various other
In 2007, President Bush added the 20-in-10 Bill Proposed to reduced gasoline consumption by 20% in
the next 10 years. Ozone “Action Days”
Days > 90°F, little or no wind Encourage to reduce emissions
World Ozone day – September 16th
Started in 1994 by the United Nations General Assembly
OTC = Ozone Transport Commission Several northeastern states (13 total) Created under Clean Air Act (CAA)
amendments in 1990 Focus on Ground Level Ozone - specifically
NOx emissions - during May – Sept ~“Ozone Season” Northeast and Mid-Atlantic regions of US
NOx Budget Program – sell or store unused allowances Regional emissions trading program
OTC recommended to EPA to set a standard for the primary ozone level to .060-.070ppm. As well as forming a secondary standard for
protection of crops during the growing season March 13, 2008 – EPA set standard to .075ppm (a
less protective threshold) and did not include a secondary standard Previous standard was .09 ppm exposure measured
over one hour (2005) OTC claims that if the standard had been set
lower benefits to the people in this region would include: Decreased respiratory problems, greater work
productivity, and reduced ER visits due to asthma incidences
California Air Resource Board (CARB) In addition to NOx, regulate VOC emissions
Overseas all air pollution control efforts in California Money from violations goes to the California Air
Pollution Control Fund Provides support for various pollution-related research
project and programs Recent News
Sited three companies for failure to comply with the Periodic Smoke Inspection program Program that regulates the smoke emissions from
fleet vehicles Fines totaled over $57,000, companies also agreed
to attend classes conducted by the California Council on Diesel Education and Technology
Fox River Valley Most smog in Wisconsin
Madison rates 47 AQI Milwaukee rates 48 AQI Wisconsin During Action Days
Combining errands Fueling car gas tanks at night
Emissions are less likely to produce ground level ozone
Mowing lawns after 6:00 p.m Properly inflating vehicle tires Carpooling, biking, walking or riding the bus to work
NASA completed a study (Aug. 2005) that when a hurricane increasing in strength, the ozone level drops These results can be used to forecast hurricanes which
could possibly strike areas of high population If the ozone layer were brought down to the
Earth's surface, air pressure and temperature conditions would compress the ozone into a layer only 2 to 5 mm thick
SmogCity.com Decide weather conditions (temp, wind speed, cloud
cover), population level, and emissions levels Shows ozone levels throughout “created” day, and
gives health warnings if levels are very high
“Sick Building Syndrome” VOC exposure indoors
Sources: photocopiers, carpets, and furnishings Most common is formaldehyde
Also tobacco smoke can contribute to high levels of VOCs
EPA has found that in some cases the VOC concentration can be 2-5 times higher indoors than outdoors
The CO2 emissions that produce near-surface global warming in return cool the stratosphere which is expected to produce an increase in O3 depletion
The chemicals which deplete the ozone are also greenhouse gases Contributing to both ozone depletion and
global warming
How does a city comply with new Ozone Standards? Largest producer targeted How long does it take to implement a new
standard? Can we lab-produce ozone and “insert” into
atmosphere? Can be lab-produced by electrolysis or with a D-cell
battery General reaction: 3 O2 — electricity → 2 O3
• EPA – “air Now”• How VOCs Contribute To Formation Of Ground-Level Ozone. Chemical &
Engineering News, 1/24/2005, Vol. 83 Issue 4, p26, 1/3p; (AN 16120478)• Chemical & Engineering News; 1/24/2005, Vol. 83 Issue 4, p25, 3p, 1c
“SMOG, POLICY AND CHEMISTRY.”• http://www.dnr.state.wi.us/org/aw/air/ozone/OzActionNotice.htm• http://www.epa.gov/Ozone/science/sc_fact.html “Ozone Science: The
facts Behind the Phaseout”• http://www.nasa.gov/vision/earth/environment/ozone_drop.html “Ozone
levels drop when hurricanes are strengthening”• http://www.ozonelayer.noaa.gov/data/antarctic.htm • “EPA’s New Ozone Standard Falls Short in Protecting the Public
Health, Says Ozone Transport Commission. Ozone Transport Commission.” March 13, 2008
• “California Adopts New Ozone Standard.” California Environmental Protection Agency. April 28, 2005.
• http://dnr.wi.gov/air/ • www.smogcity.com• http://www.ec.gc.ca/ozone/docs/UO/Primer/EN/index.cfm?p=13