ABSTRACT
This review focuses on the
environmental effects of freight
and passenger transport disaster
management and planning. It
begins with a brief overview of
major environmental mechanisms
through which transport can
affect the environment
gmuripo@live.com
HGES 401
Environmental Implications of Passenger and freight transport disaster
planning and Management
WHITE PAPER- SUBMITTED AT THE MINISTERIAL SYMPOSIUM: HARARE
ZIMBABWE -APRIL 2023
Abstract
This paper is a review of the environmental implications of passenger and freight transport
disaster planning and management. The review is structured according to transport mode
which includes air cargo, trucking, rail, pipelines, and other forms of passenger transport. It
begins with a brief overview of the major environmental mechanisms through which
transport can affect the environment. These include air pollution, global climate concerns,
noise pollution, water pollution, accidents, land use, and habitat fragmentation. The
discussions focus on air pollution, global climate issues, water pollution, accidents whose
costs are deemed to be environmental rather than primarily in human life, and certain land
use planning issues.
The paper identifies comparable emission factors for only certain kinds of environmental
harm, notably air pollution. The air pollution data conforms to the conventional wisdom that
trucking is by far the most harmful mode of freight transport. With respect to noise pollution,
the results are ambiguous. Conventional wisdom, however, holds that road noise is more than
rail and the available data confirms this. While airport noise is clearly an important problem,
comparable noise indicators are not available for road and rail.
The problems involved in the quantification and comparison of other environmental impacts
are also highlighted. The pollution caused by freight transport, for example, is only linked
indirectly to the volume of cargo in transit.
CHAPTER 1
1.0 Introduction
This paper provides an overview of the environmental impact of passenger and freight
transport disaster planning and management in Zimbabwe. It was prepared for the
ministerial symposium hosted by the Ministry of Environment on the impact of transport
disaster planning and management on the environment.
1.1 Defining Environmental Impact
Environmental impact may be considered to have three components:
- Environmental stressors such as pollutants, noise, or exotic species that are
released in natural ecosystems. Each tonne of goods transported places
additional stress on the environment, many stresses may therefore be
measured in units per tonne of goods or passengers transported.
- The amount of stress placed on the environment depends on the quantity of
goods and the distance they are ferried, in simplest form, total stress is the
quantity of goods times the distance carried multiplied by stress per tonne. The
second component of stress involves the spatial pattern of goods transported,
including the transport mode used.
- The environmental impact of the total stress is determined by the nature of the
receiving environment. Ambient characteristics such as the physical
ecosystem characteristics, the density of the population affected, and whether
the receiving ecosystem is considered critical or includes endangered species
will determine both the physical impact of the stress and the willingness to pay
to prevent it.
1.2 Quantifying and Comparing Stressors and Impacts
Some environmental stressors such as air and water pollutant emissions are easily quantified
and are directly proportional to increases in passengers and freight. Others such as airport
noise or the introduction of exotic species increase with the number of trips made, but not
with the distance travelled or quantity of freight transported. Moreover, the ecological harm
caused by such stressors may not be quantifiable or directly related to the quantity of the
freight or the number of passengers. This raises the question of how to address stressors that
cannot be expressed as emission factors per unit of freight. Three approaches may be taken to
address this issue:
- Limit the analysis of those stressors which can be easily quantified in
comparable terms, that is, pollution. These are often considered to be the most
harmful environmental impacts of transportation, and limiting the analysis to
them may not distort the results significantly.
- Include all kinds of impact but be descriptive when quantification is not
possible. This acknowledges the importance of all kinds of impacts but
unfortunately can make it easy to disregard those which are not quantified in
comparable units.
- Use valuation techniques that convert all environmental impacts to the costs
they impose, the costs of avoiding them, or the willingness to pay to avoid
them. The advantage of this approach is that it furnishes a common unit of
analysis with which to compare different kinds of impacts. The disadvantage
is that such valuation is highly subjective and quite difficult to carry out.
1.3 Overview of Impacts by Environmental Medium
This presentation is structured by transport mode. It is useful to review the major impacts of
transportation by the environmental medium in order to discuss the environmental impacts of
stressors placed by many transportation modes. This section also briefly discusses several
transportation externalities. There are several types. Some are too indirect to permit the
establishment of a clear link to freight and passenger volumes while for others data are not
available to examine them in detail by mode of transport.
1.3.1 Air pollution
Air pollution is generally considered to be the most important environmental threat posed by
transportation in Zimbabwe. The table below summarises the major pollutants emitted by
moving vehicles, their use, and the harm they can cause to ecosystems and the global climate.
Most of these pollutants are emitted by most forms of transportation.
Literature on transportation-generated air pollution generally describes the quantity of
pollution and its environmental impacts one product at a time. However, in some cases,
chemicals combine to have additional impacts beyond the problems caused by each
individually. The best-known example is that of photochemical oxidants which form through
chain reactions between hydrocarbons and other volatile organic compounds, nitrogen oxides,
and oxygen when in presence of light. this leads to the formation of photochemical smog,
which may be a potential problem in major cities such as Harare and Bulawayo. In the same
vein trace quantities of many additional pollutants are emitted by transportation; these include
benzene, toluene, cyanide, polynuclear aromatic hydrocarbons, formaldehyde, hydrogen
sulphide and so on.
Pollutant Source Impact on Impact on Global
Vegetation Climate
Carbon Incomplete Combustion Indirect through
Monoxide ozone formation
Carbon Dioxide Combustion Major Greenhouse
Gas
Hydrocarbons Incomplete Combustion, Build-up in soil, Methane has a high
Carburetion feed, food crops greenhouse
potential, leads to
ozone formation
Nitrogen Oxides Oxidation of Nitrogen Acidification of soil Nitrogen Oxide has
Compounds and water, leads to a high greenhouse
over-fertilization potential, leads to
ozone formation
Particulates Incomplete Combustion, Reduced Dirt
road dust Assimilation
Soot (diesel) Incomplete Combustion Dirt
Ozone Photochemical Oxidation Risk of leaf and root High Greenhouse
with Nitrogen and damage, lower crop potential
Hydrocarbons yields
Source: Button (1993) page 30
1.3.2 Noise Pollution
Traffic is the major source of noise particularly in urban areas and along major highways in
Zimbabwe. In addition to being unpleasant, noise contributes to health problems such as
stress, sleep disturbances, cardiovascular diseases, and hearing loss. Surveys suggest that
people feel more directly affected by noise pollution than any other form of pollution.
Measuring the magnitude of noise pollution is complex. The volume of noise is measured in
weighted decibels which is not easy to quantify.
1.3.3 Water Pollution
The normal operation of transportation vehicles does not generate water pollution in the way
that it generates air pollution. However, transportation has both direct and indirect impacts on
water quality. Shipping activity in particular, directly affects the aquatic environment. The
water quality effects of land transportation are less direct. Road accidents and vehicle exhaust
are both sources of oil and hazardous chemicals that run off the road into the surface and
groundwater.
The roads themselves, as well as parking lots, driveways, and other paved surfaces, lead to an
increase in impermeable surfaces, particularly in urban areas. Impermeable surfaces interrupt
the filtration of rainfall into groundwater. An increase in impermeable surfaces will therefore
aggravate flood risk and lead to more pollutant runoff into surface waters in heavy rains. The
problems go far beyond the choice of transport mode, however. They are primarily linked to
ownership of family cars and a preference for single-family homes which combine to create
land-use patterns characterized by a dense network of roads in order to access each residence
individually. While additional traffic means more highways and more chemicals on the
roads, the highways themselves may account for a fairly small share of impermeable
surfaces.
1.3.4 Accidents
Defining accidents as an environmental impact raises questions about how we define the
environment. Some accidents such as ship and pipeline oil spills clearly fit within any
definition of the environment. Other accidents particularly passenger transport accidents like
car and plane crushes have a narrow fit within the definition of the environment. Other
accidents fall somewhere in the middle, for example, truck accidents, train derailments, or
gas pipeline accidents which release toxic or flammable chemicals.
1.3.5 Land Use and Habitat Fragmentation
According to Van Bohemen, land transportation systems are a cause of habitat fragmentation,
the disruption of wildlife habitats, and their division into a smaller area. Transport lines cause
direct destruction of habitat by replacing it with roads, rails, and other infrastructure. A
transport right-of-way will disturb adjacent habitats through chemical pollution, noise, or
other impacts. The right-of-way creates a barrier separating functional areas within a habitat.
Many plants or animals will not cross such a barrier, so a road can have the effect of cutting
the ecosystem into two. A transport right-of-way can lead to direct collisions between
animals and moving vehicles.
The importance of road, rail lines, or pipeline as sources of habitat fragmentation will be
related to their length and width and to the habitats through which they pass. Direct habitat
loss, externalities such as pollution and noise, and road kill will be directly affected by the
volume of traffic and width of the roads. Measures are available to minimise these impacts,
by designing infrastructure such as roads and road barriers so as to minimise pollution or
lights and so on. The creation of barriers which divide ecosystems is much harder both to
analyse and to manage. The importance of such barriers is much more related to the nature of
the environment.
CHAPTER 2
2.0 TRANSPORT MODES AND ENVIRONMENTAL MEDIUMS
This chapter discusses the impact of different modes of transport’s impact on the
environmental mediums such as the impact on air pollution, water pollution, noise and on
land-use and habitat fragmentation. This discussion concentrates on air transport, road
transport, pipeline and their impact on the environment.
2.1 Air Transport
While cargo accounts for a very small portion of world-wide freight, it is growing at an
exponential rate. Moreover, with increasing concern about global warming, concern about
aircraft emissions has grown, air freight warrants consideration beyond its current importance
as a means of transport.
Air transportation can threaten the environment in three important ways. Aircraft emissions at
the take-off and landing contribute to both conventional air pollution and global warming.
Emissions during flight contribute to global warming. Noise pollution, congestion and other
land issues pose major problems around airports.
2.1.1 Low-Altitude Air Pollution
Low Altitude aircraft emissions include nitrogen oxides, carbon monoxide, and
hydrocarbons. They are converted into ozone and other compounds that comprise smog.
While aircraft emissions are minor relative to road traffic, and even relative to other means of
transporting goods, they are rising faster than emissions sources, with the growth of air travel
and air freight. Low-level pollution is emitted during the aircraft’s landing and take-off.
2.1.2 Airport Externalities
Airports are a major nuisance to those who live or work in their vicinity. The major problem
is the noise generated by planes taking off and landing. A second problem is the air pollution
generated by the planes themselves, by road vehicles bringing passengers and freight to the
airport. A third issue in some places is the road traffic congestion created by those needing
the airport. All of these issues combine in the problem of land-use planning around airports,
and particularly the conflicts which arise when airports must expand to satisfy increasing
demand.
However, there are problems involved in valuing the nuisance created by air traffic noise.
One problem is the difficulty of measuring the quantity of noise, while decibels are
commonly used, they do not take into account the duration or frequency of occurrence.
2.2 TRUCKING
The environmental impacts of trucking have received a great deal of attention, particularly in
comparison with the impacts of rail. Trucking poses threats to the environment from two
major quantifiable sources, air pollution and noise.
2.2.1 Air Pollution
Many different estimates have published a track of air pollutants emissions, based on miles
travelled, tonnage-kilometres of goods transported, quantity of energy consumed and other
measures.
2.2.2 Noise
Trucks are a significant source of road noise, and they may be more significant source of
noise than other modes of transport. Kurer has provided data on the actual level and quantity
of noise provided by trucks in Germany and concluded that the noise decibels generated is
directly proportional to the size of the trucks and the speed in km/h with which the vehicles
are travelling at.
2.3 RAIL TRANSPORT
Rail travel is generally held up as a less environmentally damaging mode of transportation
than trucking. Data on air pollution certainly confirms to this. For noise, it is somewhat less
evident, but rail may be less harmful in that respect as well.
2.3.1 Air Pollution
Air pollution from railways is substantially lower than from trucks. In the past, coal and
diesel used to power locomotives and have had a detrimental effect by releasing pollutants
into the air and ecosystems. With the advent of electric trains, the level of air pollution has
been significantly reduced to almost zero levels.
2.3.2 Noise
The noise nuisance posed by rail is generally considered to be less than that posed by trucks.
This is in large measure because railway noise is intermittent, whereas highway noise tends
to be constant. However, estimates of the noise created by an individual train passing are
higher than those for trucks. Kurer places the average noise of train at 90bB (A) as compared
to 71-74 for trucks.
2.4 PIPELINES
Pipelines are used primarily to transport oil and natural gas products. The environmental risks
posed by oil and gas pipelines are of three kinds, accidents, air pollutant emissions, and
habitat fragmentation threats to the ecosystem through which the pipeline passes.
2.4.1 Accidents
Pipeline accidents can have a number of different impacts. Obviously the most serious are
injuries and loss of life; most effort to monitor pipeline accidents focus on these concerns. In
addition, spills of petroleum products can contaminate land, surface water, or ground water.
Accidental escapes of natural gas apparently do not pose a significant environmental threat,
because it is light and disperses quickly in the atmosphere.
2.4.2 Air Pollution
Goods move through pipelines because they are either pumped (for liquids) or compressed
(for gases). The fuel flowing through the pipelines serves as the energy source for the pumps
and compressors, which emit air pollutants as would any other machine. The only available
aggregate estimates of pipeline emissions do not distinguish between oil and gas pipelines.
They do suggest, however, that pipeline transport generates substantially less air pollution
than the predominant alternatives.
CHAPTER 3
3.0 COMPARISONS AND CONCLUSIONS
This presentation has attempted to summarise the environmental impacts of freight and
passenger transport disaster management and planning on the environment, in order to
provide information concerning the impacts of transportation on the environment through
transport of goods and passengers.
The focus has been on describing the major mechanisms through which freight transportation
can affect the environment, and identifying ways to quantify those links on a per-unit of good
basis.
Some clear conclusions can be drawn by comparing the data presented in this paper. Data on
air pollution permit the most straightforward comparison. As the table below shows, despite
substantial variation among the estimates within each transport mode, trucks are clearly much
more polluting than trains or boats. This applies across all pollutants. The data suggest that
rail may be more harmful than marine transport; however, this is much less clear. The use of
different methodologies to derive the emission factors may well be more significant than any
possible generalisation about the differences between road and rail transport based on these
data.
Air Emission Ranges for Truck and Rail in grammes/tonne per km
Pollutant Truck Rail
Carbon Monoxide 0.25 - 2.40 0.02 - 0.15
Carbon Dioxide 127 - 451 41 - 102
Hydrocarbons 030 - 1.57 0.01 - 0.07
Nitrogen Oxide 1.85 - 5.65 0.20 - 1.01
Sulphur Oxide 0.10 - 0.43 0.07 - 0.18
Particulates 0.04 - 0.90 0.01 - 0.08
Volatile Organic 1.10 0.08
Compounds
Source: Primary Data
References
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Through the Year 2000" Prepared for the US EPA, Office of Noise Abatement and
Control, by Wyle Research, El Segundo, California. EPA Report no. 550/9-75-024.
2. Befahy, F. (1993) "Environment, Global and Local Effects" in ECMT (1993)
3. Button, K (1993), Transport, the Environment and Economic Policy. (Aldershot,
Hants, England and Brookfield, Vermont, USA: Edward Elgar Publishing Ltd.)
4. Cambridge Systematics, Inc. with Jack Faucett Associates, Inc. and Sierra Research
(1995), "Air Quality Issues in Intercity Freight, Interim Report" Prepared for the
Federal Railroad Administration, the Federal Highway Administration, and the
Environmental Protection Agency. August 2, 1995.
5. Kürer, R. (1993), "Environment, Global and Local Effects" in ECMT
6. van Bohemen, H.D. (1995), "Mitigation and Compensation of Habitat Fragmentation
Caused by Roads: Strategy, Objectives, and Practical Measures" Transportation
Research Record 1475. (Washington, D.C.: National Academy Press, for the
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