Fuels
This page provides an overview of the impacts on air quality arising from the use of different fuels. There has been increased focus in recent years on alternative and renewable fuels and this page provides an overview of the pollutants produced directly and indirectly from diesel, biodiesel, petrol, gas, coal and oil, wood and biomass, electric-powered vehicles, and hydrogen.
Diesel
Combustion in modern vehicles produces more oxides
of nitrogen (NOx) and particulates (PM) (including black
particulate matter) but lower carbon dioxide (CO2) emissions than
petrol. The combustion of diesel also produces water vapour, carbon
monoxide (CO), and sulphur dioxide (SO2). Benzene emissions come
from the distribution and combustion of Diesel.
More information is available from the Health and Safety Executive (HSE); the AA; and Environmental Protection UK.
Biodiesel
Biodiesel made from ‘virgin’ oils (those produced
as a result of processing fuel crops such as oilseed rape,
sunflowers, soybeans etc.) has greater negative impacts on air
quality and the environment than biodiesel created from waste
cooking oils. This is because biodiesel from ‘virgin’ oils
generates more emissions related to: transporting the fuel crops,
fuel and post-combustion waste; and, the energy used for processing
fuel crops. In addition, biodiesel made from ‘virgin’ oils uses
land that could be used for producing food crops; and also
generates waste.
Biodiesel combustion produces different levels of emissions of air pollutants than diesel combustion. It has been found that, depending on the biodiesel blend: NOx emissions can be worse; particulate emissions can be better; and sulphur dioxide emissions are better from the combustion of biodiesel compared with the combustion of diesel. In addition, less carbon dioxide and carbon monoxide emissions are produced from using biodiesel than petrol or diesel. However, the combustion of biodiesel also produces water vapour and there is some concern about odour issues regarding the combustion of biodiesel.
Biodiesel is usually sold in blends of 5% biodiesel/95% normal diesel (B5); However, there are also 20% (B20); 30% (B30); 50% (B50); and 100% (B100) biodiesel fuels. Check with your vehicle manufacturer to ensure that you can run your vehicle on biodiesel.
More information on biodiesel blends can be found from Veggie Power; Green Gold Biodiesel; Green Energy and Rix Biodiesel.
More information on biodiesel refuelling points can be found from the Energy Saving Trust and Biodiesel Filling Stations .
Petrol
Combustion of petrol in modern vehicles produces
less NOx and particulates than diesel but more than LPG. Levels of
carbon dioxide emissions are dependent on the fuel efficiency and
other efficiencies of the vehicle. Benzene emissions come from the
distribution and combustion of petrol. The combustion of petrol
also produces water vapour, carbon monoxide, and sulphur
dioxide.
More information is available from the AA and Environmental Protection UK .
Gas - Liquid Petroleum Gas (LPG) and Compressed Natural Gas (CNG)
LPG vehicles tend to produce lower levels of emissions across a range of air pollutants compared to petrol, biodiesel and diesel fuelled vehicles. CNG fuelled vehicles produce less carbon dioxide emissions than LPG vehicles.
More information is available from Environmental Protection UK ; Energy Saving Trust ; Autogas ; The Greenfuel Company ; Green Consumer Guide ; Green Car Guide .
Emissions from gas appliances in the home and at work include NOx; water vapour; carbon dioxide and carbon monoxide. Carbon monoxide poisoning can be caused by gas appliances and flues which have not been properly installed or maintained.
Lower emissions are produced from gas combustion compared to oil, wood/biomass, and coal combustion.
More information is available from the Health and Safety Executive (HSE).
Coal and oil
Coal combustion produces significant emissions of NOx;
particulates (which include trace elements of mercury, selenium and
arsenic); carbon dioxide; carbon monoxide; water vapour; and
sulphur dioxide. Oil combustion generally produces lower emissions
than coal, but more than wood/biomass. Different grades or types of
coal and oil produce different levels of air pollutant emissions
under combustion.
More information is available from the World Coal Institute.
Wood and Biomass
Wood and biomass combustion produces emissions of NOx;
particulates (possibly including trace elements); carbon dioxide;
carbon monoxide emissions; sulphur dioxide; and some water vapour.
Compared with coal and oil, wood/biomass combustion generally
produces lower emissions.
Installation of biomass boilers, heaters and other appliances; bonfires and illegal fuel burning are heavily discouraged in Ealing due to the significant impacts on air quality (including those arising from the transportation of biomass fuel); and statutory nuisance and legal implications (especially regarding the Clean Air Act 1993.
Ealing is a smoke control area , which means that only exempt appliances and authorised fuels can be used without a permit. More information related to waste incineration and the links between the Clean Air Act and Pollution Prevention and Control is available from UK Smoke Control Areas .
More information on the impacts on air quality resulting from wood fuelled biomass use is available from London Councils .
Electric Powered Vehicles
There are a number of electric and electric-hybrid
vehicles on the market. Electric vehicles have the lowest air
quality impacts of any vehicle type, apart those that are powered
by you - i.e. bicycles. If the electricity used to charge vehicles
comes from a non-renewable source - the combustion of fossil fuels
(i.e. coal) in power stations etc. - air quality impacts occur from
the pollutants emitted.
More information is available from Environmental Protection UK ; and the Energy Saving Trust .
Hydrogen
There are a limited number of hydrogen-powered vehicles
and fuel cells available. Hydrogen fuel is normally produced from
either the breakdown of a hydrocarbon source (natural gas, fossil
fuels or ethanol) or by the electrolysis of water. Combustion of
hydrogen produces water vapour and therefore it is considered to be
a completely clean fuel. However, the process of producing hydrogen
can be very energy intensive which does have significant air
quality impacts if the energy generated for the production process
comes from fossil fuelled (i.e. coal) power stations.
More information is available from the London Hydrogen Partnership ; Energy Saving Trust ; and Environmental Protection UK .