Class Project Report, May 2005 ME/ChE 449 Sustainable Air Quality

1
Class Project Report, May 2005 ME/ChE 449
Sustainable Air Quality

• Highway Transportation
• Trends from 1970 to 2002 and Beyond
• By
• Scott Kaminski
• Instructor
• Rudolf B. Husar
• Washington University, St. Louis, MO

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Data Consistency

• Number of vehicles, miles driven, and fuel
  consumption data given in six categories by the
  FHWA1
• Passenger Cars
• Buses
• Motorcycles
• Other 2-Axle, 4-Tire Vehicles
• Single Unit Trucks
• Combination Trucks

• Emissions data given in four categories by
  EPA2
• Light Duty Gas Vehicles and Motorcycles (LDGVMC)
• Light Duty Gas Trucks (LDGT)
• Heavy Duty Gas Vehicles (HDGV)
• Diesels

• Categories from FHWA converted to EPA Categories
  through3
• LDGVMC .9864 (Passenger Cars) Motorcycles
• LDGT .9918 (Other 2-axle, 4-tire vehicles)
• HDGV .1028 (Buses) .7994 (Other Single Unit
  Trucks)
• Diesels .0136 (Passenger Cars) .0082 (Other
  2-axle, 4-tire vehicles) .8972 (Buses) .2006
  (Other Single Unit Trucks) 1.0000 (Combination
  Trucks)

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Emissions
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Important Emission Improvements

• 1968 Tailpipe emission standards first
  implemented for new cars to reduce VOC and CO
  emissions.6
• 1970 Congress passes the Clean Air Act which
  calls for a 90 reduction in emissions by 1975.
  This deadline is later extended to 1980 for VOC
  and 1981 for NOx and CO emissions.7
• 1971 - New cars have to meet evaporative
  emission standards for the first time and
  charcoal canisters are introduced to collect VOC
  vapors.7,8
• 1972 - Exhaust gas recirculation valves are
  implemented to reduce NOx emissions.7
• 1975 Most new cars have catalytic converters to
  reduce VOC and CO emissions.8 Unleaded gasoline
  introduced (with a 13 market share) since lead
  inactivates the catalytic converters. Market
  share climbs to 50 in 1982 and 100 in 1996.9
• 1980/81 In response to implementation of CAA
  emission standards, new cars are equipped with
  three-way catalysts that optimize the efficiency
  of catalytic converters and reduce NOx
  emissions.7
• 1983 Passenger Vehicles are first required to
  undergo testing for malfunctioning emission
  control systems.7

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• 1990 CAA Amendments passed including increasing
  testing requirements.7 Limit on diesel fuel
  sulfur content (to reduce SO2 and PM emissions)
  is set by EPA to take effect in 1993.9
• 1991 Lower tailpipe standards set for VOC and
  NOx emissions to be phased in beginning in 1994.7
  NOx emissions standards for new trucks and buses
  cut in half.10
• 1992 Limits for CO emissions at cold
  temperatures are set to be phased in beginning in
  1994.7
• 1993 The Diesel PM standard for urban buses is
  reduced. This standard is further reduced in
  1994 and 1996.11
• 1999 SUVs subject to same emissions standards
  as other vehicles for the first time. More
  restrictive standard for VOC, CO, NOx, and PM
  begin to be phased in (end 2008).7 Standard for
  sulfur content in gasoline is reduced to take
  effect in 2005.12
• 2000 Standard for sulfur content of diesel fuel
  is again reduced to be phased in between in 2007
  2010. By cleaning up the fuel, emission
  control technologies can finally be implemented
  in Diesel vehicles.13

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CO Emissions

• Overall emission trends determined by LDGVMC
  emission trends.
• Steeper drop after 1987 because by then average
  vehicle age (7-8 years)6 suggests that the
  average car was purchased after the 1980/81
  improvements.
• Leveling off after 1996 in LDGVMC due to aging
  of fleet prior to replacement with MY 1994 and
  later vehicles and continued increase in vehicle
  use.
• The similarity in 2002 emissions per gallon (LDGT
  4.2 better grams/gal emissions factor than
  LDGVMC) is deceiving because LDGVMC have a
  26.1 better MPG than LDGT and so LDGVMC will
  produce less emissions for the same trip.

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NOx Emissions

• Overall emissions trends determined by LDGVMC
  and Diesels.
• Rise in Diesel emissions due to increased use and
  lack of emission technology for vehicles.
  Decrease after 1998 due to stricter MY 1991
  emissions standards for truck and buses.
• NOx emissions can be significantly reduced by
  improving Diesel NOx emission technology Diesel
  NOx emission factor is 7 times that of the
  overall NOx emission factor and absolute Diesel
  NOx emissions are greater than the other three
  vehicle categories (46 of total).

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VOC Emissions

• Overall emission trends determined by LDGVMC
  emission trends.
• Lower emissions for HDGV, LDGT, and Diesels
  because of less use, as shown in miles driven.
• The greater reduction in VOC emission factors
  over NOx emissions factors (85.2 to 77.1
  LDGVMC) can be attributed to improvements in
  evaporation emission technology as well as
  exhaust emission technology.

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SO2 Emissions

• Overall emissions trends determined by Diesels
  SO2 emissions minor compared to NOx (23 times in
  2002) and VOC emissions (26).
• Large emissions factor (Diesel 10 times that of
  LDGVMC in 1990) prevails over a lesser amount of
  Diesel vehicles use.
• Drop after 1990 in both absolute emissions and
  emissions factors corresponds to desulphurization
  of diesel fuel.
• Little change in LDGVMC over time since this
  emission source is minor and thus has yet to be
  dealt with for LDGVMC.

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PM-10 Emissions

• Overall emissions trends determined by LDGVMC
  and Diesels.
• Incline of emission factor from 1980 1987 can
  be attributed to an aging vehicle fleet.
• Drop after 1990 in both absolute emissions and
  emissions factors corresponds to desulphurization
  of diesel fuel.

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Emissions Summary

• The trends are a result of the competition
  between the effectiveness of the emission control
  technology in the national vehicle fleet and
  vehicle use.
• The decrease in emission factors for each
  pollutant shows that emission technology is
  working.
• The decrease in absolute emissions shows that
  emission technology is progressing faster than
  the increase in vehicle usage.
• Difference between improvements in emissions
  factors and absolute emissions (ex. 85.2
  decrease to 73.1 decrease for overall VOC) is
  the increase in vehicle use .
• Full advantage of emission technology can only be
  achieved through reduced vehicle use.

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References

• United States. Office of Highway Policy
  Information. Highway Statistics Summary to 1995
  (Historical Summary to 1995) Table VM-201a.
  April 1997. http//www.fhwa.dot.gov/ohim/summary9
  5/vm201a.pdf 23 March 2005.
• United States. Environmental Protection Agency.
  1970 - 2002 Average annual emissions, all
  criteria pollutants. January 2005.
  ttp//www.epa.gov/ttn/chief/trends/trends02/trends
  reportallpollutants010505.xls 22 March 2005.
• Tooly, Rebecca Lee. Procedures Document For
  National Emission Inventory Criteria Air
  Pollutants 1985-1999. United States Office of
  Air Quality. Environmental Protection Planning
  and Standards Agency. Research Triangle Park.
  NC March 2001. http//www.epa.gov/ttn/chief/tren
  ds/procedures/neiproc_99.pdf 22 March 2005.
• United States. Environmental Protection Agency.
  What are Mobile Sources? http//www.epa.gov/otaq/
  invntory/overview/examples.htmonr 31 March
  2005.
• Dill, Jennifer. Transportation Research Board.
  Older Vehicles and Air Pollution Insights from
  the 1995 NPTS. http//gulliver.trb.org/publicati
  ons/circulars/ec026/23_dill.pdf. 17 April 2005.
• United States. Environmental Protection Agency.
  Mobile Source Emissions - Past, Present, and
  Future Milestones. http//www.epa.gov/otaq/invn
  tory/overview/solutions/milestones.htm. 13 April
  2005.

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1. United States. Environmental Protection Agency.
   Automobile Emission An Overview.
   http//www.epa.gov/otaq/consumer/05-autos.pdf. 17
   April 2005.
2. United States. Environmental Protection Agency.
   National Air Pollutant Emission Trends
   1900-1998. March 2000. http//www.epa.gov/ttn/chi
   ef/trends/trends98/chapter3.pdf. 17 April 2005.
3. United States. Environmental Protection Agency.
   Diesel Exhaust in the United States. September
   2002. http//www.epa.gov/otaq/retrofit/documents/
   f02048.pdf 24 April 2005.
4. United States. Environmental Protection Agency.
   Motor Vehicles and the 1990 Clean Air Act.
   http//www.epa.gov/otaq/consumer/11-vehs.pdf. 17
   April 2005.
5. United States. Environmental Protection Agency.
   EPA National News. CLEANER CARS AND CLEANER
   FUELS FOR THE 21ST CENTURY. 21 Dec. 1999.
   http//yosemite1.epa.gov/opa/admpress.nsf/b1ab9f48
   5b098972852562e7004dc686/0b8d5154df6d30a18525684e0
   077437d?OpenDocument. 20 April 2005.
6. United States. Environmental Protection Agency.
   Environmental News. EPA DRAMATICALLY REDUCES
   POLLUTION FROM HEAVY-DUTYTRUCKS AND BUSES CUTS
   SULFUR LEVELS IN DIESEL FUEL. 21 Dec. 2000.
   http//www.epa.gov/otaq/regs/hd2007/frm/r-196.pdf
   20 April 2005.