T.Schneider et al. (Editors),Atmospheric Ozone Research and its Policy Implications 0 1989 Elsevier Science Publishers B.V., Amsterdam -Printed in The Netherlands
MOTOR VEHICLE CONTRIBUTION TO GLOBAL AND TRANSPORTED AIR POLLUTION Michael P.Walsh') and Curtis A.Moore 2) 1 ) Consultant, 2800 North Dinwiddie Street, Arlington, Virginia 22207, USA 2) Minority Counsel, Committee on Environment and Public Works, U.S.Senate, Washington D.C. 20510, USA
Motor vehicles generate more air pollution than any other single human activity. They are the dominant source of carbon monoxide, oxides of nitrogen, and hydrocarbons, as well as a significant source of carbon dioxide and, particularly in the U.S., chloroflurocarbons. All of these cause or contribute to the formation of ground level ozone. Some also destroy stratospheric ozone or contribute to its destruction.1,Z Concentrations of ground level ozone are increasing, and stratospheric ozone is being destroyed globally. During the Antarctic spring a "hole" the size of North America is depleted of ozone and, at certain altitudes, is destroyed almost completely because of manmade chemicals.3 Researchers who recently reanalyzed a European data set on tropospheric ozone concentrations from the turn of the century concluded that ozone concentrations had doubled over the past 100 years.4 One commentator described the finding "as remarkable as the observation of a hole in the stratospheric ozone layer over Antarctica and potentially is just as consequential."' Pollutants emitted by motor vehicles are a major cause of each of these environmental threats. Means of abating these pollutants are both economically and technically feasible, but they are being implemented at a rate far short of what technology would allow and prudence would dictate. MOTOR VEHICLE SHARE OF OECD POLLUTANT EMISSIONS* (1000 tonnes, 1980) POLLUTANT
3 3 ,869
their precursors are Ozone, acidic compounds, and transported over great distances. There is recent evidence that even carbon monoxide is transported over great distances.l,a
Some of these compounds react with each other in ways only recently understood. For example, hydroxyl radicals (OH) which scavenge many anthropogenic and natural trace gases from the atmosphere, are themselves removed by carbon monoxide. CO increase, tropospheric Therefore, as concentrations of concentrations of OH decrease, thus allowing other trace gases (e.g. methane and reactive hydrocarbons) to accumu1ate.B , l o EFFECTS
Human health: Controlled human exposures and field studies at frequently encountered ambient levels of ozone have demonstrated that it causes healthy, exercising children, adolescents, and young adults to lose lung function;11 and, children in day camp to experience a linear increase in lung decrement with increased exposure time, with decreased lung function for up to one week;1*,1a When levels of ozone increase, so do hospital admissions for pulmonary distress.l',ls In animal studies, chronic exposure to ozone causes serious morphological change, including cell damage to ciliated and non-ciliated cells, increases in inflammatory cells, distal airway narrowing and lesions similar to those observed in smokers.14,lT Some researchers have concluded that air pollution in the United States, especially fine particles, may cause 2 to 4 percent of the nation's excess mortality.18 Ozone's precursors and associated pollutants also damage human health. Oxides of nitrogen, for example, caused significant decrements in pulmonary function in subjects with chronic emphysema who were exposed while performing bronchitis or moderate exercise.19 Benzene, a demonstrated human carcinogen, causes anemia, bone-marrow hypoplasia and other diseases in laboratory animals.'@ Lead destroys intelligence in children, increases susceptibility to infectious agents, and causes 50,000 deaths per year of heart attack and stroke in United States among white males over the age of 40.21,2* Forest Damages: Forest declines ("Waldsterben") throughout Europe and Eastern North America have focused considerable press attention on "acid rain" from sulphur dioxide and oxides of nitrogen.23 A more likely explanation for these declines may be ozone or ozone in combination with acid deposition and other air pollutants, or in combination with natural stresses (e.g. insects) . a 4 Visible symptoms of Waldsterben first appeared in Europe in 1979-80 and within four years the disease had spread over large areas of the continent. As of late 1985, the disease was still increasing in intensity and geographic area. It is associated with an alarming frequency of damage from secondary stress factors such as insects, needle and root fungi, and climatic stress such as frost, wind and emow damage. It now
affects virtually every tree species in Europe including the four most important conifers (spruce, fir, pine, larch) and six angiosperms (beech, birch, oak, ash, maple and alder). According to one analysis, European damage is worst in West Germany, where 55 percent of the trees are injured, followed by Switzerland, 33 percent of the stands are suffering from where "Waldsterben" . a 5 , * a The government of the United States views the nature, extent and possible causes of forest damage in North America more conservatively.2' This view is not shared by non-governmental observers.Za Although not assembled in a single government document, there are nonetheless reliable reports of extensive damage to yellow pine, white pine, red spruce, fraser fir, sugar and yellow maple, beech, birch, red maple and a wide variety of other tree species throughout eastern North America.2n , 3 0 , 3 1 , 3 2 , 3 3 Field and other experiments have confirmed that levels of ozone commonly encountered throughout the eastern United States can cause significant reductions in growth and net photosynthesis.S4,3Sl One scientist has concluded that-(1)n areas where known anthropogenic air pollution takes place, trees are in fact statistically more symptomatic than trees from non-polluted areas, trees from polluted areas are in fact significantly more suppressed in terms of their growth rates over the past 25-30 years as compared to non-pollutant sites and surface soils have in fact accumulated lead, often an order of magnitude above that of non-polluted region soils. 3 8 Aquatic and soils effects. Ozone is not reported to directly impact either soils or aquatic ecosystems, but oxides of nitrogen may. Sulfuric acid and nitric acid increase the levels and toxicity of some metals, including mercury and aluminum." They also acidify soils, accounting for the extensive acidification of deep soil horizons'in many sensitive areas.08 Crop damages. The U.S. National Acid Precipitation Assessment Program has estimated that ozone damage to agricultural crops is about $1 billion per year in the United States.a* Buildings and materials. More than two decades o f research have established that ozone reacts with both natural and man-made materials to destroy their integrity or otherwise cause damage. The most susceptible materials are textiles, elastomers, and paints . 4 0 EMISSIONS Europe: As source of air
noted earlier, motor vehicles are the major pollution, including ozone, throughout Europe.
Virtually all of the lead and carbon monoxide in cities and an increasing proportion of the fine particles originates with vehicles. OECD recently noted that "The primary source category responsible for most NOx emissions is road transportation roughly between 5 0 and I0 per cent...Mobile sources, mainly road traffic, produce around 50 per cent of anthropogenic VOC emissions, therefore constituting the largest man-made VOC source category in all European OECD countries."41 U.S.: During 1985, transportation sources were responsible for 73 percent of nationwide lead emissions, 70 percent of the CO, 34 percent of the volatile organic compounds (HC), 4 5 percent of the NOx, and 18 percent of the particulate. In some cities, the mobile source contribution is even higher. Growth in vehicle miles travelled and less stringent controls on other mobile sources are reducing the overall gains from the automobile standards. According to EPA estimates,'2 the overall reductions in emissions from all transportation sources across the U.S. during the last decade were 88 percent for lead, 2 5 percent for CO, and 30 percent for HC. These reductions occurred despite a 26 percent increase in vehicle miles travelled during this same time period. However, because standards for these pollutants have been more lenient or implemented later, overall reductions have been only 1 percent for NOx and there has been no reduction in particulate. GLOBAL IMPACTS OF MOTOR VEHICLE POLLUTANTS
To put the global problems with motor vehicle pollut on in perspective, it is important to realize that motor vehicle usage has increased tremendously in a relatively brief period of time. In 1950, less than 50 million cars were on the world's roa s , 85 percent of them in North America. Only one generation later, the car popu1,ation is approaching 350 million, almost a seven fold increase.43 Outside North America, the growth has been especially high, from slightly under 7 million in 1950 to 125 million by 1980. While the rate of growth has slowed in the highly industrialized countries, population pressures, increased urbanization and industrialization are accelerating motor vehicle growth in other areas. Whereas the number of people in Europe and the U.S. is increasing moderately, the global population is expected to double (compared to 1960 levels) by the year 2000, driven by more than a doubling in Asia and an almost 150 percent increase in Latin America. Beyond the overall growth in population, an increasing portion of Asia's and South America's people are moving to cities, driving up the global urban population." One result is that global automobile production and use are projected to continue to grow substantially over the next decade. By the year 2000, the global vehicle population will likely exceed 500 million, with annual car production rising from about 3 3 million today to about 38 million.45
Ozone destruction and production. Motor vehicles produce ground level ozone both directly and indirectly. Vehicular emissions of NOx and HC directly cause ground level ozone by reacting to form it. Other pollutants emitted by motor vehicles produce ground level ozone indirectly by destroying stratospheric ozone. Ozone in the stratosphere blocks ultraviolet radiation from the sun. But ozone is also created by this same solar radiation, which fractures oxygen (02) molecules, allowing them to recombine as ozone (03). As stratospheric ozone is destroyed by chemicals, the amount of ultraviolet radiation penetrating to ground level-and the ozone which it produces--increases. The chemicals which destroy stratospheric ozone, and thus indirectly increase ground level ozone, are chloroflurocarbons (CFCs) (more commonly known in the United States by the DuPont Corporation’s tradename of Freons).46 CFCs are used in vehiclular air conditioners. About 40 percent of the United States production of CFCs and 30 percent of European production is devoted to refrigeration. Mobile air conditioning accounted for 56,500 metric tons of CFCs--28 percent of the CFCs used for refrigeration in the United States, or about 13 percent of total production. In contrast, home refrigerators accounted for only 3,800 metric tons.47 Thus, approximately one of every eight pounds of CFCs manufactured in the U.S.is used, and emitted, by motor vehicles. (CFCs also are used as a blowing agent in the production of seating and other foamed products but this is a considerably smaller vehicular use. Global climate destruction. Motor vehicles also emit substantial quantities of trace gases which increase global temperatures, destroying prevailing climates. Hothouse gases emitted by (or attributable to) motor vehicles include carbon dioxide (COZ), CFCs, nitrous oxide (N20), methane (CH4), water and, ground level ozone.48 CFCs are the most potent hothouse gases, now contributing about over a third of the total global warming effect.49 Carbon dioxide is the other major hothouse gas. A single tank of gasoline produces between 300 and 400 pounds of C02 when burned.50 Motor vehicles emit about 2.77 gigatons of C02 per year, which is 13.5 percent of the world’s production. In the U.S., motor vehicles are responsible for 23.5 percent of the total C02 emissions.51 Doubled C02 concentrations (or the trace gas equivalent thereof) are projected to increase the global average temperature between 1.5 and 4.5 degrees Centigrade.32 Changes likely to accompany this temperature increase include the following: large stratospheric cooling (with the potential to accelerate stratospheric ozone depletion); global mean precipitation increase; reduction of sea ice; polar winter surface warming; summer continental dryness; high latitude precipitation increase; and, rise in global mean sea level.53
Other consequences which investigators have suggested include failure of the Asian monsoons and sudden onset of a European ice age.3 4 ,5 3 Partially because of recent unexplained extreme events (e.g. drought, proliferation of icebergs, etc.) some commentators have begun to speculate whether the global climate destruction has already begun to occur.66 The years 1 9 8 1 , 1 9 8 3 and 1 9 8 7 are reported to be the hottest on rec0rd.s'
Mobile Sources: Before emission reductions were mandated, gasoline vehicles emitted pollutants at the rates listed in Table A , which also displays the current U . S . requirements. TABLE A Vehicle Emissionst Pol1u tant
Hydrocarbons Exhaust Crankcase Evaporative Carbon Monoxide Oxides of Nitrogen
8.2 4.1 2.9 90 3.5
Current .41 3.4 1.0
1: Exhaust emissions as determined by the 1 9 7 5 U . S . Federal Test Procedure, expressed in grams per mile.
Initial Controls: To meet the relatively lenient HC and CO standards that applied in the early 1 9 7 0 ~ 1 ,auto manufacturers generally relied on enleanment of the air/fuel mixture and modification of spark timing. Newer combustion chamber designs were introduced to reduce hydrocarbon emissions, with faster flames to limit increased nitrogen oxides. When HC and CO standards were tightened, the engine modification approach continued to predominate, with the addition of certain new wrinkles such as transmission controlled spark timing and antidieseling throttle control. Attainment of initial HC and CO standards with limitations on NOx increases was generally possible without significant fuel consumption penalties. However, as emissions standards were tightened (especially in 1 9 7 3 and 1 9 7 4 ) it became more and more difficult for domestic cars employing conventional engine designs to achieve low levels of CO, HC and NOx without unacceptable compromises in performance or fuel economy. As a result there was a fundamental shift in the technology to the catalytic converter. Catalysts: Two
basic types of catalysts have been developed
- oxidation and three way.
An oxidation catalyst converts HC and CO to carbon dioxide and water. Three-way catalysts are so called because they lower three pollutant levels--HC, CO and NOx--simultaneously. First introduced in the U.S. in 1977, they are now almost universally used on cars and light trucks there and in Japan. Because they require .that air-fuel ratios be precisely controlled, three-way catalysts have fostered improved air-fuel management systems including advanced carburetors, throttle body injection, and electronic controls (ironically, leading General Motors to become the world largest producer of computers). Diesel Fueled Vehicles: To solve the air pollution threats in many areas would require improvement in the currently inadequate controls on diesel fueled vehicles, which not only emit NOx, HC, and particulate, but pose a significant cancer risk.58 In the U.S. attention has focused particularly on diesel trucks and buses, leading to the adoption of standards intended to spur technological developments similar to those which occurred for cars. Basic approaches to diesel engine emission control fall into three major categories: 5 9 1 6 0 1 6 1 1: engine modifications, including combustion chamber configuration and design, fuel injection timing and pattern, turbocharging and EGR; 1: exhaust aftertreatment, catalysts; and
1: fuel modifications, including control of fuel additives, alternative fuels.
NOx controls being phased into the diesel population now include variable injection timing and pressure, charge cooling, and exhaust gas recirculation. Retarding injection timing, while a well established method of reducing NOx formation, can lead to increases in fuel consumption, particulate and hydrocarbon emissions. These problems can be mitigated by varying the injection timing with engine load or speed. Also, high pressure injection can reduce these problems. Coupled with electronic controls, these and other techniques could simultaneously reduce NOx and improve fuel economy. REGULATIONS AND STANDARDS AROUND
THE WORLD The evolution of vehicle controls since crankcase regulations in 1963, has made dramatically lower vehicle emissions through one of the following: ( 1 ) engine modifications (2) controls and ( 3 ) in-use controls. Increasingly,
the first U . S . it possible to or a combination add-on catalytic countries around
the world have been taking advantage of them, although with different degrees of stringency. Japan and the United States currently impose the most stringent emissions controls, but as knowledge of these technological developments has spread and the damage caused by vehicular pollutants has become evident, more and more nations have imposed controls. For example-t The Netherlands and the Federal Republic of Germany have adopted innovative economic incentive approaches to encourage purchase of low pollution vehicles; and,
+ Canada, Austria and Switzerland have decided to implement U.S. standards for the 1988 Model Year, while Norway and Sweden will do so by 1989; + Australia has adopted standards similar to those used in the U.S. in the mid to late 1 9 7 0 ' s when catalyst technology was first introduced. A Divided Europe: In many ways, Europe is a microcosm of global motor vehicle issues--confronted by rapid environmental deterioration and an ensuing public outcry and its manufacturers able to build either clean or dirty vehicles, Europe's governments are moving toward tighter and tighter controls, but at a pace which is much slower than technology would allow. This is largely because the nations of Europe are sharply divided.
Members of the so-called Stockholm Group, including Austria, Norway, Sweden and Switzerland, have adopted state-of-the-art emissions requirements. Perhaps more importantly, the group has retained the U.S. 1975 Federal Test Procedure ( ' 7 5 FTP) to judge whether manufacturers are complying with the law. Because these nations are not members of the EEC, they were free to act on their own. The EEC nations have adopted more lenient tailpipe standards and test procedures embodied in the "Luxembourg compromise", which is a non-binding guideline. While member states are free to adopt the provisions of the Luxembourg compromise, they are equally free to reject them and continue to rely on the older, Because EEC members are barred binding standards of R 15-04. from requiring more stringent controls, a schism has developed that threatens the Community's unity. Nations like West Germany and the Netherlands are encouraging motorists to buy clean cars by offering tax breaks, while Denmark has threatened to unilaterally align itself with the Stockholm Group. To accurately measure the
the standards of the
Luxembourg compromise, it is necessary to compare their outcomes with those of the test procedures adopted by the Stockholm Group procedure (the ' 7 5 FTP), as follows: Stockholm Group levels ( 0 . 4 1 grams per mile HC, 3 . 4 CO, 1.0 would be in the range of 1.5 to 2.5 grams per teat for HC, 1 5 to 2 0 CO, and 1 . 5 to 2 . 5 for NOx. The best single point estimate of the standards is estimated at 2 . 2 grams per test HC, 2.4 NOx and 16 CO. The Luxembourg compromise standards as summarized below are much more lenient than these levels, up to three times higher depending upon vehicle size.
under 1.4 liters
1.4 to 2 . 0
A key ingredient of all programs directed toward state of the art emissions standards is the widespread availability of unleaded gasoline. At this time, most major automotive markets in the world have introduced unleaded fuel and when it is mandated across the Common Market by the end of the decade, it appears that the era of leaded fuel will be finally drawing to an end.
CONTROL O P T I O N S
Mobile sources: Although emissions from cars have been substantially reduced from uncontrolled states, further reductions could be achieved by tightening tailpipe standards (especially on trucks, buses, heavy duty engines, and dieselpowered vehicles); imposing in-use controls (e.g. inspection and maintenance programs); switching fuels (e.g. natural gas or, in limited cases, methanol); or changing vehicle use patterns (e.g. lowering speed limits). Proposals to adopt changes in many of these areas are being seriously considered throughout the world. United States: Legislation awaiting Senate consideration in the U . S . Congress would lower emissions from both gasoline and diesel powered vehicles in an effort to reduce air pollution in the roughly 7 0 cities where air quality levels are unhealthy. These are summarized below.
Automobiles (Light Duty Vehicles) Carbon Monoxide ICOI Hydrocarbons (HC) Oxides of Nitrogen INOX) Particulate Light Duty Trucks (Above 6000 lbs. CVW) Carbon Monoxide (CO) Hydrocarbons (HC) Oxides of Nitrogen (NOx) Particulate Heavy Duty Trucks grams/brake horsepower hour Oxides of Nitrogen (NOx) Particulate
0.41 1.0 0.2
0.25 (1992) 0.4 (1990) 0 . 0 8 (1990)
grams/mile 5.0 (1990)
0.8 2.3 0.26
0.50 (1990) 1.7 (1990) 0.5 (1992)
10.6 5.0 (1991) 0.25 (1991)
6.0 (1990) 4.0 (1991) 1.7 (1995) 0.25 (1991)
Cold starts: Because U . S . data show that emissions of carbon monoxide from motor vehicles are higher when the ambient temperature is low and the engine is cold (so-called “cold starts“), the bill addresses this specific problem. It requires that at temperatures between 2 0 and 6 8 degrees Fahrenheit CO emissions be reduced by 90 percent from 1970 levels. At 20 degrees, this new level is calculated to be 6.2 grams per mile. Similar legislation has been introduced in the House of Representatives, but delayed by the opposition of the Committee Chairman, Rep. John Dingell of Detroit, Michigan, home of the major U . S . automakers. Both bills would also make impose additional requirements on use of motor vehicles, including more stringent inspection and maintenance programs and controls on refueling emissions. Europe: Small cars represent almost 6 0 percent of the car population in Europe and their Standards are scheduled to be tightened during the 1990’s. Should they be lowered to levels in the range of 15 grams per test CO, and 2 grams per test each for HC and NOx, the overall environmental impact of the package could improve considerably. If relatively weak levels (for example, equal to or more lenient than the medium car standards of 30 CO and 8 for HC plus NOx, as proposed earlier this year by the
European Commission) are adopted, the Community will be condemned to serious air pollution problems well into the next century. Global: Mobile source C02: Mobile source emissions of carbon dioxide could be substantially reduced through the use of more fuel efficient vehicles. For example, in late 1 9 8 5 , the Toyota Corporation tested a prototype model AXV which utilizes presently available technologies (e.g. low weight, low aerodynamic drag, direct injection diesel engine, and continuously variable transmission). The car received an EPA fuel economy rating of 9 8 miles per gallon on the combined urban/highway test. , By comparison, U . S . automobiles average 19 mpg and non-U.S. cars about 2 4 mpg. 6 1 Global: Mobile source CFCs: Significant reductions in CFC releases could be achieved through improvements in air conditioner seals and, especially, through changes in repair shop work practices because CFCs are intentionally vented to the air when air conditioners are repaired. CFC consumption in the U.S. has been estimated as follows: ESTIMATED U . S . CONSUMPTION OF CFC-12 FOR MOBILE A/C (1000 TONNES)O' Use Initial charge of units U.S.
Imported Aftermarket Recharge of Units After leakage After service venting After accident
X of Total
27.2 5.2 1.8
13.5 18.2 3.9
25.0 33.6 7.2
Compliance Programs For In Use Vehicles: To comply with emission standards in-use, cars must be maintained properly. Inspection and Maintenance (I/M) programs are essential to assure this and therefore a key element in the control programs of many countries.64 While I/M programs in the U . S . have focused on HC and CO control, countries such as Germany have taken the lead in exploring the feasibility of I/M for NOx and diesel particulate control. Stationary sources: NOx controls: Technologies are currently available and in use for the control of oxides of nitrogen from stationary including low NOx burners (up to 7 0 percent reduction from uncontrolled states); and selective catalytic reduction
(SCR) (90 percent or greater reduction). To date SCR has been installed on more than 100 units in Japan and more than 50 in Germany. NOx can also be reduced through the use of combustion systems such as fluidized bed and integrated gasificationcombined cycle, but a detailed discussion of these is beyond the scope of this paper.65 Due in part to the availability of these control options, major revisions of air quality regulations have been adopted by a number of European nations, including Belgium, West Germany, Hungary, and Switzerland.66 CONCLUSIONS
Motor vehicles account for more of the world’s air pollution than any other human activity. They are responsible for virtually all of the carbon monoxide and lead in the air of cities, and a major portion of the NOx, VOC’s, fine particles and toxic chemicals. In addition, as the major consumer of oil in the world, vehicles also emit substantial amounts of carbon dioxide and other gases which contribute to giobal warming. Due to expanded CFC use in vehicle air conditioners, vehicles also play a significant role in the stratospheric ozone depletion. The d a m g e caused by vehicular pollutants is becoming inescapably apparent. Increases in the number of vehicles and the number of vehicle mile travelled is overwhelming the reductions which have been achieved to date, although almost fifty percent of all new cars produced this year are equipped with state of the art emissions controls. The Common Market countries of Europe stand out as the slowest industrialized area to implement state of the art requirements. It is likely that unless the Community moves closer to the standards of the Stockholm Group Europe will see further deterioration of its environment. More stringent small car standards, on the order of 16 grams per test CO and 2 grams per test each for HC and NOx, would represent a large step in the right direction. While NOx and particulate control technologies for diesel cars are not as advanced as for gasoline cars, progress is accelerating and very low levels have been demonstrated. Emission control of trucks and buses is of particular importance because of past neglect, but fortunately, it appears that technologies developed for cars can be transferred. Eliminating the use of CFCs in automotive air conditioners or, in the short term prohibiting unnecessary venting to the air, would not only protect the stratosphere, but the troposphere as
well. Mandatory fuel efficiency standards throughout the world would slow the growth in C02 emissions which are increasing global temperature and destroying prevailing climates. However, continued growth in the number of vehicles and their use is undercutting the overall benefits of these technological gains. The global vehicle population has climbed from under 50 million just one generation ago to more than 350 million. By the year 2000, it is projected to exceed 500 million. Unless this growth is constrained, global pollution will continue to increase, many areas which currently have relatively clean environments will deteriorate, and the few areas which have made progress will see some of these gains erode. With the increasing likelihood that the global changes will be irreversible and of unknowable proportions, it is imperative that the nations of the world confront and surmount these obstacles. Otherwise, as 250 of the world's scientists warned in Villach, Austria in December, 1985 "Mankind is conducting a gigantic experiment with the Earth's future without knowing the outcome.' ' 6 7
1. OECD Environmental Data, Organization operation and Development, Paris, 1987.
2. Regulatory Impact Analysis: Protection of Stratospheric Ozone, Environmental Protection Agency, Washington, D.C. (December, 1 9 8 7 ) 3. Testimony of F.S. Rowland and R. Watson, Committee on Senate, Washington, D.C. Environment and Public Works, U . S . (March 30, 1 9 8 8 ) . ' 4 . A. Volz & D. Klev. "Evaluation of the Ozone Measurements Made in the Nineteenth ( 1 9 8 8 ) 240-43.
5. S.A. Penkett, "Atmospheric Chemistry: Ozone," Nature 332 ( 1 9 8 8 ) 204.
Montsouris Series of Century," Nature 332
6. OECD, n. 1.
7. Khalil, M.A.K. & Rasmussen, R.A., "Carbon Monoxide in the Earth's Atmosphere: Indications of a Global Increase", 332 Nature 245 (March, 1 9 8 8 ) . 8 . Acid Rain and Transported Air Pollutants: Implications for Public Policy (Washington, D.C.: U.S. Congress, Office of Technology Assessment, OTA-0-204, June, 1 9 8 4 ) .
9 . Testimony of D.R. Blake before the Committee on Energy and Natural Resources, U.S. Senate, Washington, D.C. (Nov. 9 , 1 9 8 7 ) .
lO.Thompson, A.M. b Cicerone, R.J., "Atmospheric CH4, CO from 1 8 6 0 to 1 9 8 5 , 3 2 1 Nature 1 4 8 - 5 0 ( 1 9 8 6 ) .
11. W.F. McDonnell, D.H. Horstman, et. al., Pulmonary Effects of Ozone Exposure During Exercise:Dose-Response Characteristics, JAppl. Physiol.:Respir. Envir. Exercise Physiol. 54 ( 1 9 8 3 ) 1 3 4 5 - 5 2 . 1 2 . M. Lippman, J.H. Cunningham, et.al., "Effect of Ozone on the Pulmonary Function of Children," Advance in Modern Environmental Toxicology. Ed: S . D . Lee, et.al. Princeton Scientific Publishers, 1983.
1 3 . P.J. Lioy, T.A. Vollmuth & M. Lippman, Persistence of Peak Flow Decrement in Children Following Ozone Exposures Exceeding the National Ambient Air Quality Standard. J. Air Poll. Control Assn. 3 5 ( 1 9 8 5 ) 1 0 6 8 - 7 1 . 1 4 . D.V. Bates & R. Sizto, Relationship between air pollution levels and hospital admissions in Southern Ontario, Can. J . Public Health 7 4 ( 1 9 8 3 ) 1 1 7 - 2 2 . 1 5 . D.V. Bates 8 Sizto, A Study of Hospital Admissions and Air Pollutants in Southern Ontario, Aerosols, Eds. S.D. Lee, et. al. Lewis Publishers, Chelsea, Michigan ( 1 9 8 6 ) . 1 6 . D.V. Bates, "The Effects of Ozone on Individual and Human Populations," North American Oxidant Symposium, Ministere de 1'Environment du Quebec, Quebec (Feb. 1 9 8 7 ) . 1 7 . Ibid. 18. H. Ozkaynak, J . Spengler, et. al. Health Effects of Airborne Particles, Energy and Environmental Policy Center, John F. Kennedy School of Government, Harvard University, Boston (Feb.
1 9 . Bauer, 1 9 8 6 ,
2 0 . M.I. Luster & J.A, Blank, "Molecular and Cellular Basis of Chemically Induced Immunotoxicity," Ann. Rev. Pharmacol. Toxicol. 27 ( 1 9 8 7 ) 3 7 .
2 1 , Ibid. at 3 2 . 2 2 . The Nature and Extent of Lead Poisoning in Children in the United States: A Report to ConRress (Draft), Agency for Toxic Substances and Disease Registry, U.S. Department of Health and
Human Services, Atlanta, Ga. (1988). 23. M. Keating, "Withering Death of Forests Spreading Across the East," The Globe and Mail, Toronto, Canada, August 6, 1987. 24. G.H. Weyerhauser, "Ozone, Not Acid Rain, Main Forest Growth," Financier IX (December 1985) 34-36.
25. World Resources 1986, World Resources Institute, Washington, D.C. (1986)v p. 204-5. 26. P. Schutt & E. Cowling, "Waldsterben--a General Decline of Forests in Central Europe: Symptoms, Development and Possible Causes," Plant Disease 69 (1985) 448-58. 27. Review, n. 16, at X-24. 28. American Forestry Association, "The Forest Effects Pollution," Am. Forests, Nov./Dec., 1987, pp. 37-44.
29. R.I. Bruck,. "Decline of Boreal Montane Forest Ecosystems in Central Europe and Eastern North America-Links to Air Pollution and the Deposition of Nitrogen Compounds," EPA-EPRI Joint Symposium #18, New Orleans, La. (1987). 30. H.A. Knight, "The Pine Decline," J. of Forestry, pp. 25-28.
31. S.M. Zedaker, et. al., "Growth Declines in Red Spruce," J. of Forestry, 85 (1987) 34-6. 32. Review, n. 16, pp. X-26-28. 33. 33. Joint Report to Bilateral Advisory and Consultative Group: Status of Canadian/U.S. Research in Acidic Deposition, U.S. National Acid Precipitation Assessment Program (NAPAP), Washington, D.C., Feb. 1987. 34. D. Wang & F.H. Borman, "Regional Tree Growth Reductions Due to Ambient Ozone: Evidence From Field Experiments," Environ. Sci. Technol., v. 20, no. 11 (1986) pp. 1122-25. 35. P.B. Reich & R.G. Amundson, "Ambient Levels of Ozone Reduce Net Photosynthesis in Tree Species," Science, 230 (Nov. 1985) 566-70, 36. Bruck, n.29.
37. P. Campbell, P. Stokes, & J. Galloway, "Acid Deposition: Effects on Geochemical Cycling and Biological Availability of Trace Elements," Tri-Academy Committee on Acid Deposition, National Acad. Press, Washington, D.C. (1985). 38. C.O. Tamm & L. Hallbacken, "Changes in Soil Acidity in Two Forest Areas with Different Acid Deposition: 1920s to 19809," Ambio 17 (1988) 56-61. 39. Interim Report of the National Acid PreciDitation Assessment Program (NAPAP): Executive Summary, NAPAP, Washington, D.C. (19871, p. 1-9. 40. Review, n. 16, pp. X-36-40. 41. "An Emission Inventory For S02, NOx and VOC's in N o r t h Western Europe", Lubkert, de Tilly, Organization for Economic Cooperation and Development, 1987. 4 2 . National Air Quality and
Emissions Trends Report 1985, U . S . Environmental Protection Agency, Washington, D.C. (1987). 43.
MVMA Motor Vehicle Facts and Figures, MVMA, 1986
44."World Resources 1986 - An Assessment of the Resource Base that Supports the Global Economy". World Resources Institute and the International Institute for Environment and Development. New York: Basic Books, Inc., 1986. 45. OECD (1982), "The Future of the World Automobile Industry", OECD Directorate for Science, Technology and Industry, Paris. 46. Stratospheric Ozone: The State of the Science and NOAA's Current and Future Research, National Oceanic and Atmospheric Administration, Washington, D.C. (1987) pp. 11-15. 47. Regulatory Impact Analysis, note 2 . 48. DeLuchi, M.A. Greenhouse Effect,", Record.
et.al., "Transportation Fuels and the submitted to the Transportation Research
49. Ramanathan, R.J., et.al. "Trace Gas Trends and Their Potential Role in Climate Change," J. of Geophysical Research, 9 0 (1985) 5547-66.
5 0 . Private communication, Office of Technology Assessment, U.S. Congress ( 1 9 8 8 ) . 5 1 . DeLuchi, n. 5 0 . 5 2 . Current Issues in Atmospheric Change, Board on Atmospheric Sciences and Climate, National Academy of Sciences, National Academy Press, Washington, D.C. 1 9 8 7 , p. 9 . 5 3 . Ibid at 9 - 1 0 . 5 4 . T.P. Barnett, et. al., "The Effect of the Eurasian Snow Cover on Global Climate," Science, 2 3 9 ( 1 9 8 8 ) 5 0 4 - 7 .
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History, 9 6
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