whereWHK/di ;mj represents the quantity of cargo transported from
Hong Kong to a destination di in tonnes using that transportation
mode mj, Wdi/HK;mj is the quantity of cargo transported from the
destination di to Hong Kong in tonnes using the same transportation
mode mj, DISTHKdi ;mj is the path distance between Hong
Kong and the destination di using the transportation mode mj, EFmj
is the emission factor of the transportation mode mj in g CO2-eq/
tonne-km (or tonne CO2-eq/kilotonne-km) of cargo, and k is the
total number of destinations for the transportation mode mj.
Hence, the total amount of GHG emissions from the logistics
services in a particular year is given in Eq. (2) as follows