Californias Congruence

1
Californias Congruence

• California has one of the most benign climates in
  the world - adequate precipitation input in the
  mild winters and warm, sunny, calm, cloud-free
  summers.
• California has extraordinary natural beauty with
  an extremely favorable arrangement of mountains,
  hills, valleys and plains.
• Together, these factors helped provide the
  magnetic attraction that continues to bring waves
  of migrants to enjoy the lifestyle and economic
  opportunity the state has represented.
• But the congruence of the climate, the landscape,
  the people, the lifestyle and the economic
  opportunity created a monster - air pollution aka
  SMOG.

2
Air Quality Distribution

• California is divided into 15 air basins - based
  on a mixture of jurisdictional and
  physiographical boundaries - by the CA Air
  Resources Board (http//www.arb.ca.gov/homepage.ht
  m).
• Responsibility for managing air quality within
  those regions are given to air quality management
  districts e.g. BAAQMD based in Oakland.
• California atmospheric hot-spots - South Coast,
  South Central Coast and Southeastern Desert
  regions (especially LA Basin), Sacramento and San
  Joaquin Valley regions (especially Sacramento and
  Fresno) and the San Francisco Bay region.
• Problem free areas are largely in the
  little-populated regions of the North.

3
15 Basins formed from adjacent counties
4
Principal problems

• Californias principal problems relate to primary
  carbon monoxide and microparticulates (PM10),
  deposition of nitric and sulphuric acids, and the
  occurrence of secondary photochemical pollutants
  like ozone.
• The majority of these pollutants come from mobile
  sources - principally gasoline and diesel burning
  vehicles.
• Hence, the worst concentrations occur immediately
  over or in the airsheds of regions with intense
  concentrations of vehicle use Fnumber of
  vehicles, number of miles driven, amount of fuel
  consumed per mile, and rate of pollutant output
  per unit of fuel consumed.

5
Non-Attainment Areas, 2000
OZONE
PM10
CO
Non-attainment areas are the brown shaded basins
and counties.
6
SMOG

• In the 80s SMOG was so bad in CA that the area
  surrounding LA was deemed by an act of Congress
  to have extreme air pollution.
• In 1988, CAs own ground level ozone standards
  were exceeded on 216 days in the South Coast, 188
  days in the Southeastern Desert, 160 days in San
  Diego, 154 days in the San Joaquin Valley, 135
  days on the South Central Coast, 98 days in the
  Sacramento Valley, and 41 days in the San
  Francisco Bay regions.
• Autopsies performed on otherwise healthy young
  male traffic and homicide victims in LA showed
  75 suffered from unexpected chronic lung
  inflammation (Hall, 1993).

7
SMOG Control

• The 1990 revision of the Federal Clean Air Act
  required California to meet all health-based
  standards by 2010.
• California was expected to reduce per capita
  exposure to CO, NOx and O3 by 25 by 1994, 40 by
  1997 and 50 by 2000 (Hall 1993) (hence
  recognizing the difficulty in achieving each
  incremental improvement).
• A basic problem was that the average CA resident
  had already reduced their pollution significantly
  since 1980 and were about 2/3 the national
  average already.
• As mentioned previously, population increases
  plus intense concentrations of population in
  pollution-concentrating locations made air
  quality improvement extremely difficult.

8
Pollution and Respiration

• With every breath, we take in from 200 to 500 cm3
  (12 to 30 in3) of air depending on our anatomy
  and level of exertion.
• Thus, in our lifetime we will probably all inhale
  between 126 and 315 million liters of air.
• Even if there is only one part per million of a
  pollutant in the air, that would mean breathing
  in between 126-315 kg over a lifetime or 275-700
  .
• Childrens lungs are much smaller than adults,
  with smaller alveoli (bronchial endings) that are
  easily blocked, irritated or damaged (why asthma
  is a common childhood illness).
• We not only breathe in harmful primary pollutants
  like carbon monoxide (CO) and dust and soot, etc.
  (PM10s), but also secondary pollutants such as
  Ozone (O3) and nitrogen dioxide (NO2).

9
California Sunshine

• Sunlight is an important energy source for the
  production of secondary pollution in CA cities.
• Chemical molecules absorb the suns photons and
  dissociate into two or more products - a process
  called photodissociation i.e. AB hv ? A B
• Most dissociation involves ultraviolet radiation
  and is a function of a molecules coefficient of
  photodissociation.
• Molecules that cleave readily into fragment
  species are termed photolytically unstable (have
  large coefficients).
• Molecular oxygen (O2) is relatively easily
  photodissociated into atoms (O O) and will
  quickly associate with another O2 molecule (O
  O2) to form ozone O3.

10
The Internal Combustion Engine

• The modern internal combustion engine is still
  relatively inefficient - it cannot perform
  stoichometric combustion.
• If an engine could mix gasoline (HCs) with the
  right amount of air (containing O2) and be burned
  to completion, the only significant byproducts
  would be H20 and CO2.
• But modern engines are not stoichometric and
  still leave an unburned mix of CO and
  non-combusted reactive hydrocarbons (RH) in their
  exhaust emissions.
• Moreover, molecular nitrogen N2, which is
  photolytically very stable, is heated up enough
  to fuse with oxygen to produce nitric oxides N2
  O2 Heat ? NO NO
• NO is reactive and can form nitrogen dioxide
  (NO2) and nitrous oxide (N2O) which are problem
  pollutants.

11
Smog Chemistry

• The overall process of smog formation can be
  chemically simplified as
• RH OH NO ( hv O2)? HC NO2 O3
• Where RH is the unburned, reactive hydrocarbons
  from gasoline engines plus other key urban
  sources such as evaporating paints, pesticides,
  charcoal starter and dry cleaner agents, fumes
  from leaky gas pumps, refinery vapors, isoprene
  from certain ornamental trees, aerosol
  propellants, etc.
• The hydrocarbons, ozone and nitrogen dioxides
  continuously react in the presence of sunlight
  and each other to produce hundreds of different
  secondary compounds, many of which are harmful -
  this is SMOG.

12
Smog Health Effects

• Ground level ozone (O3) damages and ages cells,
  including human lung and skin cells and plant
  tissues.
• Ground level ozone also irritates the eyes, nose,
  throat and lungs and causes headaches.
• NO2 HNO3 formation promotes surface diseases on
  the lungs, causes bronchitis, asthma, respiratory
  failure and heart attacks.
• Peroxyacetylnitrate (PAN) causes tearing and
  conjunctivitis (pink eye).
• Carbon monoxide (CO)causes time distortion,
  drowsiness and headaches.
• There are many other physical and ecological
  effects from SMOG as well as health ones.

13
Production of Primary Pollutants

• According to Turco (1997), daily in the LA basin
  some 5m kg of CO, 1.1m kg of NO, 1.4m kg of RH
  and 1.1m kg of PM10s are emitted.
• Mobile pollution sources (cars) account for
  between 10 and 60 of these various PPs.
• PPs are emitted mostly during commute hours, with
  the morning commute from 6-9am being critical.
• When air is stable (no breeze) or trapped by a
  temperature inversion (cold air over warm), PPs
  build up.
• Photodissociation peaks just after noon when the
  sun is at its highest and most intense.
• Secondary pollutants peak at different times -
  NO2 at around 10-11am, HCs at around 12pm and O3,
  PAN and Formaldehydes at around 3-4pm.

14
Solving the Smog Situation

• Smog concentrations can only be controlled by
  cutting emissions and/or altering the timing of
  their release since all other factors are
  environmentally determined.
• Installing catalytic converters and other
  pollution control devices and modifications.
• Eliminating smokers or gross polluters from the
  roads.
• Requiring existing cars to be well maintained and
  tuned (as verified by smog checks).
• Reducing car usage (decreasing number of trips
  number of miles driven per trip).
• Encouraging rapid introduction of
  LEVs/ULEVs/ZEVs.
• Changing fuel formulation to raise stoichometric
  level of combustion.

15
Heavy Focus on Vehicular Sources

• Making vehicles less likely to pollute - engine
  type, engine efficiency, and pollution output -
  switching to low, ultra-low and zero emission
  vehicles e.g. electric, natural gas.
• Making people less likely to use those vehicles -
  increasing vehicle occupancy, reducing frequency
  of use, selecting mass transit alternatives.
• Making usage of those vehicles less polluting -
  requiring cleaner burning gasoline formulations
  in 1992 methyl tertiary butyl ether MTBE was
  added to CA gas at about 11 by volume.

16
Fuel Oxygenates

• To reflect the fact that the gradual phasing in
  of LE ZE vehicles would take time and the trend
  towards stagnating and even decreasing average
  fuel efficiency of the passenger fleet, CA and
  the federal EPA favored the use of oxygenates in
  gasoline to increase stoichometric combustion.
• For a very comprehensive site on oxygenates see
  http//www.arb.ca.gov/cbg/Oxy/oxy.htm
• Several alternatives existed Ethanol, ETBE
  (Ethyl TBE), TAME (Tertiary Amyl Methyl Ether)
  and TBA (Tertiary Butyl Alcohol).
• Principally based on availability, cost and oil
  industry preferences, the mandatory use of MTBE
  was decided upon.
• While only required for non-attainment markets,
  the geography and economics of refinery operation
  required its shipment to gas stations in many
  areas where it was not needed i.e. where smog
  levels were generally low e.g. Tahoe.

17
Claimed Benefits

• The State of California claimed the following
  benefits from cleaner burning gasoline with MTBE
  oxygenates (http//www.arb.ca.gov/cbg/pub/cbgbkgr1
  .htm)
• MTBE oxygenated gasoline would immediately reduce
  emissions from all the motor vehicles and
  motorized equipment that use it, regardless of
  its age or the sophistication of its
  emission-control equipment.
• The emissions reductions would be equivalent to
  taking approximately 3.5 million motor vehicles
  from California's roads and highways over ten
  years.
• The emission of pollutants from on-road motor
  vehicles in California would be reduced by more
  than 3 million pounds per day - an approximate
  15 percent reduction.
• The cleaner-burning gasoline would reduce human
  cancer risk related to gasoline exposure by 30 to
  40 percent.

18
Scientific Findings

• A 1998 UC study on oxygenated fuels, especially
  those using MTBE, found, among other things
• No significant effect on pollution emission from
  advanced technology vehicles (i.e. newer cars
  with cleaner engines).
• Significant risks of contamination of surface and
  groundwater sources from the highly soluble
  additive, a possible carcinogen.
• That a cost-benefit study showed that all in all,
  non-oxygenated fuel actually achieves air quality
  benefits at the lowest cost if the true value of
  water clean-up, higher fuel prices and lower fuel
  efficiency are considered.
• That it would be cheaper to remove older, highly
  polluting cars from the road with tax credits and
  other incentives than to continue using MTBE as
  an oxygenate.
• That the state should phase out MTBE, use it very
  selectively, and carefully study all other
  substitute oxygenates should the federal laws
  still require their use in CA non-attainment
  basins.

19
Adding Oxygenates

• Gasoline is made up of over a 100 hydrocarbon
  species plus many additives to help improve
  engine performance.
• Lead was favored until the 1970s. It became a big
  health problem and was removed but its
  replacements have increased smog potential.
• Fuel oxygenates like MTBE increase the chemical
  reactions during combustion that convert the
  hydrocarbons chemical energy to thermal energy,
  creating more CO2 and less CO and leaving less
  unburned RH in emissions.

20
MTBE Health Concerns

• The USEPA has tentatively classified MTBE as a
  possible human carcinogen on the basis of studies
  that show MTBE is a carcinogen in animals,
  although no human epidemiological studies exist
  to provide conclusive data.
• Rats and mice exposed to MTBE by inhalation or
  ingestion showed increased incidence of benign
  and malignant tumors, and lymphomas and
  leukemias.
• MTBE is absorbed rapidly and extensively from the
  respiratory and gastrointestinal tracts.
• MTBE and its metabolites show little tendency to
  distribute and accumulate in tissues, although
  some evidence suggests they temporarily
  accumulate and then are slowly excreted over a
  longer period of time.
• MTBE is not expected to bioaccumulate in food
  webs.

21
MTBE solubility

• When gasoline that has been oxygenated with MTBE
  comes in contact with water, large amounts of
  MTBE can dissolve e.g. at 25 degrees Celsius the
  water solubility of MTBE is about 50 times that
  of the total hydrocarbon solubility from
  nonoxygenated gasoline (USGS, 1998).
• Atmospheric MTBE solubility in precipitation
  appears strong enough to allow for up to 3
  micrograms per liter (µg/L) (3ppbv) or more of
  inputs of MTBE to surface and ground water via
  this indirect route (USGS, 1998).
• Gasoline with MTBE can contaminate large amounts
  of water 1 gallon of reformulated gasoline mixed
  with 4 million gallons of water will yield 20
  µg/L MTBE in the water (USGS, 1998).

U.S. Geological Survey National Water Quality
Assessment Program (NAWQA) Fact Sheet FS-203-96
(Revised 2/98)
22
Figuring Out Point/Non-Point Origins

• Where high concentrations of MTBE (greater than
  30 µg/L) are detected in ground water, the source
  of contamination is probably a point source, such
  as a leaking underground storage tank (LUST).
• When small concentrations (0.2 to 3 µg/L) of MTBE
  are detected in ground water, the source of
  contamination may be a point source but more
  likely is a non-point source such as atmospheric
  washout.
• MTBE plumes originating from point-source
  releases generally spread quickly through a large
  volume of the subsurface and will initially
  exhibit small concentrations but will
  subsequently increase with time at the same
  location.
• USGS studies have generally shown the highest
  concentrations of MTBE in normal urban stormwater
  runoff to be less than 10 µg/L.

23
MTBE persistence

• If not washed out onto the ground and into soil
  or water bodies, MTBE may have a relatively short
  half-life of around 3 days.
• However, when in water, soil and rock, MTBE does
  not biodegrade easily under many environmental
  conditions i.e. it is said to be chemically
  recalcitrant.
• The fact that it does not sorb to soil or other
  media means it can thus move as fast as the water
  it is in.
• MTBE's high water solubility and resistance to
  biodegradation complicates its removal from
  water.
• There have been several evaluations of remedial
  technologies for MTBE, but these have generally
  indicated low efficiency and high costs.
• For example, activated carbon filters would need
  to be huge and are quickly exhausted.

24
Remediating MTBE in Groundwater

• Techniques currently used to remove other
  gasoline related contaminants like Benzene are
  less effective with MTBE.
• Currently, the only effective large-scale
  techniques seem to be pumping out the
  contaminated water and treating it by air
  sparging (bubbling though huge quantities of air
  to off-gas the MTBE) and chemical treatment of
  the water with hydrogen peroxide and UV.
• The EPA estimated the cost per 1,000 gallons
  treated (in 1990) at 15-16 (for a unit with
  25gpm capacity achieving 50 removal from a
  starting concentration of 20ppb) (EPA Fact Sheet
  Jan 1998, 510-F-97-015) remember the 4 million
  gallons contaminated to 20ppb by a single gallon
  of gas the impact . 60,000 of clean up costs.
• The cost per 1000 gallons at 15-16 is thus over
  10 times the cost of regular treated drinking
  water w/out pumping costs, etc.
• The cost of treating an acre-foot of groundwater
  that had to be freed of MTBE prior to use as a
  drinking water source would thus be around 5,000
  compared to typical pumping costs of 100-300.
• Note that the size of unit for 50,000 people
  would be 5,000gpm!

25
Practical Solutions

• Clearly, we must conclude that relying on
  remediation (addressing the symptom, not the
  cause) will not work prevention is critical.
• However, remediation is necessary to deal with
  contamination that has already occurred and which
  exceeds drinking water standards for health or
  aesthetic levels.
• As long as the potential exists for gasoline
  leakage into the sub-surface, MTBE will migrate
  to and contaminate groundwater (already locally a
  problem in So. Lake Tahoe, Santa Monica, Santa
  Clara, Sacramento).
• Data from studies by University of California
  suggest that each year, between 0.7 and 2.7 of
  UST systems fail and leak, depending on their age
  and type.
• This type of information has been one of the
  major reasons why CA has decided to ban MTBE use
  by 2002 and is encouraging the EPA to ban its use
  nationwide.
• The abilities of atmospheric washout to locally
  pollute water to above aesthetic thresholds and
  close to suspected health levels is another key
  reason for its ban.