In the case of passenger rail transport the activity data are available from timetables. Rail freight
movements are more complicated, and data are
generally more difficult to obtain. There are essentially three types of freight movement: long-term
scheduled, short-term scheduled, and “on
demand.” Clearly, it would be difficult to incorporate on-demand movements in any emission
calculations. Encouragingly, an increasing number of operators are adopting “black box” technologies, which can provide useful journey and fleet
information. For example, in Germany, the rail
company Deutsche Bahn has installed equipment
to monitor the real-time location and energy consumption of its locomotives [97]. However, at the
moment, it appears that access to the data from
train event recorders is rather limited.
The primary source of information on ship
movements is the database provided by Lloyd’s
Maritime Information Service. The database
includes ship size, destination, approximate time
of arrival and departure, engine type and number,
but only for ships greater than 500 gross tons.
Ferries, fishing vessels, and operations at smaller
ports are not included. Port calling statistics are
also available from national sources. In the future,
the availability and accuracy of activity data and
emissions data should improve further due to
onboard GPS technology, continuous emission
monitoring systems (CEMS) and the development
of a universal Automatic Identification System
(AIS) [98]. For inland shipping there is currently
a need for data that give a better description of the
fleet, the traffic, and the waterways.
Pollutant Dispersion and
Transformation
Once pollutants have been released into the atmosphere, they are subject to various processes of
dispersion and physical or chemical transformation. Emissions from transport are also superimposed on emissions from other sources.
Figure 9 shows a simplified representation of pollutant concentrations in and around an urban area
with tall commercial buildings in the urban center
and low residential buildings in the surrounding
districts. The regional background pollution originates from a range of sources, extends over a
wide area, and is relatively invariant outside the
urban area. Within the built-up area there is an
additional “urban background” component. This
results from combined emission sources located
within the urban area, including transport, power
plant, industry, and domestic heating. Alongside
heavily trafficked roads there is also likely to be a
significant local contribution to the concentration.
Dispersion
The dispersion of pollutants is influenced to a
large extent by the local weather conditions (see
Chapter, ▶ “Urban Air Quality: Meteorological
Processes”). In particular, the temperature
Urban structure (km)
Regional background
Urban background
Local traffic sources
Pollutant concentration
Air Quality, Surface
Transportation
Impacts on,
Fig. 9 Simplified
representation of urban
structure and pollution
levels. (Adapted from [18])
62
Air Quality, Surface Transportation Impacts on
movements are more complicated, and data are
generally more difficult to obtain. There are essentially three types of freight movement: long-term
scheduled, short-term scheduled, and “on
demand.” Clearly, it would be difficult to incorporate on-demand movements in any emission
calculations. Encouragingly, an increasing number of operators are adopting “black box” technologies, which can provide useful journey and fleet
information. For example, in Germany, the rail
company Deutsche Bahn has installed equipment
to monitor the real-time location and energy consumption of its locomotives [97]. However, at the
moment, it appears that access to the data from
train event recorders is rather limited.
The primary source of information on ship
movements is the database provided by Lloyd’s
Maritime Information Service. The database
includes ship size, destination, approximate time
of arrival and departure, engine type and number,
but only for ships greater than 500 gross tons.
Ferries, fishing vessels, and operations at smaller
ports are not included. Port calling statistics are
also available from national sources. In the future,
the availability and accuracy of activity data and
emissions data should improve further due to
onboard GPS technology, continuous emission
monitoring systems (CEMS) and the development
of a universal Automatic Identification System
(AIS) [98]. For inland shipping there is currently
a need for data that give a better description of the
fleet, the traffic, and the waterways.
Pollutant Dispersion and
Transformation
Once pollutants have been released into the atmosphere, they are subject to various processes of
dispersion and physical or chemical transformation. Emissions from transport are also superimposed on emissions from other sources.
Figure 9 shows a simplified representation of pollutant concentrations in and around an urban area
with tall commercial buildings in the urban center
and low residential buildings in the surrounding
districts. The regional background pollution originates from a range of sources, extends over a
wide area, and is relatively invariant outside the
urban area. Within the built-up area there is an
additional “urban background” component. This
results from combined emission sources located
within the urban area, including transport, power
plant, industry, and domestic heating. Alongside
heavily trafficked roads there is also likely to be a
significant local contribution to the concentration.
Dispersion
The dispersion of pollutants is influenced to a
large extent by the local weather conditions (see
Chapter, ▶ “Urban Air Quality: Meteorological
Processes”). In particular, the temperature
Urban structure (km)
Regional background
Urban background
Local traffic sources
Pollutant concentration
Air Quality, Surface
Transportation
Impacts on,
Fig. 9 Simplified
representation of urban
structure and pollution
levels. (Adapted from [18])
62
Air Quality, Surface Transportation Impacts on