712 MOBILE SOURCE POLLUTION
than fi fty per cent of the total particulate matter emitted from
aircraft engines appears to be due to unburned and partially
oxidized fuels. More detailed analysis of this constituent
must await development of improved measurement tech-
niques. About 90 per cent of the non-hydrocarbon material
present is elemental carbon (i.e., smoke), while the remainder
is material eroded from the engine, fuel contaminants, or dust
ingested by the engine. Fuel additives containing metallic
compounds are seldom used for normal aircraft operations.
The emission of such metallic particles does not appear to
constitute a problem.
It has been demonstrated that fuel-rich pockets in the pri-
mary combustion zone of the burner were the source of the
smoke-producing carbon particles and that the smoke could
be reduced by “leaning out” the fuel-rich areas. Redesign of
the burner is believed to be the most effective approach to
smoke reduction.
The author wishes to acknowledge the assistance of
Mr. George Musser, Exxon Research and Engineering
Company, for his discussion on particulate matter emis-
sions, of Dr. William Peterson, formerly of the Polytechnic,
for supplying test procedure information, and of Mr. John
Pinto of the New York City Department of Environmental
Protection for his review.
The particulate problem most often cited for diesel engines
in PM-2.5 emissions.^39 The 2.5 refers to the particle aerody-
namic diameter, d, in microns, m and the PM refers to the
concentration in m/m^3 of particulate matter of d 2.5 m.
An Environment Defense report estimated that in New YorkHarbor alone, ferries, tugboats, container ships and other
commercial vessels produce as much smog-forming con-
tamination over the course of a year as do 300,000 automo-
biles.^40 These sources were largely unregulated as of 2005. It
has been noted by the International Maritime Organization
(IMO) that in terms of emission intensity—emissions per
ton of cargo transported—marine shipping is one of the most
environmentally effi cient methods of shipping. According
to the IMO, between 85–90% of all commodities are trans-
ported by ships, and diesel engines power the majority of
these vessels.^41 The diesel engines have become more effi -
cient in recent years. New air pollution rules expected to be
in effect will require diesel and gasoline engine emission
level equivalence by 2010.REFERENCES- US EPA and US DOE, “2005 Fuel Economy Guide”, http://www.
fueleconomy.gov - Beard, R.R. and G.A. Wertherm, Amer. J. Public Health 57 , 2012
(1967). - Shy, C.M. et al., J. Air Poll. Cont. Ass. 20 , 539 (1970).
- Heuss, J.M., G.J. Nebel, and J.M. Colucci, J.A.P.C.A. 21 , 535 (1971).
- Report AP-66, US Dept. of H.E.W., March, 1970.
- Benson, J.D. and R.F. Stebar, Paper presented at S.A.E. Meeting,
Detroit, Mich., Jan., 1971. - Shelef, M. and J.T. Kummer, Chem. Eng. Prog. Symp. Ser. 67 , 74
(1971). - Wise, H. and M.F. Frech, J. Chem. Phys. 20 , 22 (1952).
- Fraser, J.P. and F. Daniels, J. Phys. Chem. 62 , 215 (1958).
- Yuan, E.L. et al., J. Phys. Chem. 63 , 952 (1959).
- Taylor, F.R., Air Poll. Foundation Rept. No. 28 (1959).
TABLE 6
Particulate trapping—federal 7-mode cycle^28Car, year, and make Miles Exhaust systems Particulates, total g/mile Pb
1970 make D 6,000 Standard 0.169 0.046
6,000 Anchored vortex 0.139 0.039
% Reduction 19 16
1970 make B 6,000 Standard 0.274 0.071
6,000 Anchored vortex 0.227 0.056
% Reduction 17 21
1970 make A 6,000 Standard 0.471 0.114
6,000 Anchored vortex 0.189 0.043
% Reduction 60 66
1970 make D 0 Standard 0.116 —
0 Agglom.-inertial # 1 0.037 0.006
% Reduction 68
16 cars (1966–1969) 30,000 Standard 0.339 0.060
1965 make D 24,000 Agglom.-inertial # 2 0.125 0.036
% Reduction 63 39
1969 make D 12,000 Agglom.-inertial # 3 0.108 0.034
% Reduction 67 43
1970 make D 12,000 Agglom.-inertial # 4 0.098 0.019
% Reduction 71 68C013_005_r03.indd 712C013_005_r03.indd 712 11/18/2005 10:42:30 AM11/18/2005 10:42:30 AM