Generally the concentration of other emission types is very small, but some compounds can still have severe adverse effect on human health. Other emissions can for example be heavy metals known to the harmful to human health. Numerous other organic compounds such as benzene are found in the category and are highly toxic. The heavy metal group comprises cadmium, chromium, copper, mercury, nickel and zinc and generally reflects the heavy metal content of the fuel oils being burned. Heavy metals can cause damage to the marine fauna and cause cancer in humans.
Emission Rates from Ship Machinery
Ship emission rates can be stated brake specific (g/kWh) or fuel specific (g/kg fuel oil) depending on convenience for the species of emission. The emission rates stated here are only for primary emissions – the emissions coming from the ship – and not the secondary formed ones like ozone.
It is straightforward to calculate the amount of CO2 emitted from an engine running on any kind of fuel. The amount emitted depends on the number of carbon atoms in the chains of hydrocarbons that constitute the fuel. The CO2 emission is generally independent of engine power and only varies with the amount of fuel burned. The calculations are based on the molecular weight of carbon, oxygen and CO2. The molecular weights are for the three reactants respectively: 12.01, 16.00, and 44.01. The conversion factor can be found from the carbon content and the basic reaction:
C + O2 → CO2