Cleaner air from improved fuel quality standards

By David Swanton

First published in Air Ouality and Climate Change Volume 53 No.1. March 2019 (journal of the Clean Air Society of Australia and New Zealand, CASANZ).

Revised version published in Online Opinion, 8 October 2019.


Australia’s air quality, particularly in urban areas, is adversely affected by noxious emissions from motor vehicles. The amount and type of these emissions are determined by vehicle technology and the quality of hydrocarbon fuels. The preference of the expert Intergovernmental Panel on Climate Change is that zero emission electric or renewable fuel vehicles ought to prevail that would eliminate noxious and greenhouse gas emissions and improve people’s health and the environment. 


Until zero or low emission vehicles prevail, the Australian Government must remake the fuel quality standards established under the Fuel Quality Standards Act 2000by 1 October 2019 (Department of the Environment and Energy 2018a). Otherwise they will sunset, with potentially dire consequences for vehicles and motorists. Fuel quality standards achieve beneficial outcomes for Australians by ensuring engine operability, maximising vehicle performance and reducing noxious and greenhouse gas emissions.

The Government has for some time been progressing regulatory processes and consulting stakeholders on proposed fuel quality standards, including the development of a regulation impact statement (Department of the Environment and Energy 2018b), as well as standards for noxious emissions and fuel efficiency. If improved health outcomes, vehicle performance and reduced noxious and carbon dioxide emissions are a priority, then the preferred implementation option is clear: fuel quality standards must be raised to international best practice.

Australia imports all its vehicles and is also a net importer of crude oil and many refined products. Internationally harmonising Australia’s fuel quality is necessary as new vehicles are designed to use the quality fuels recommended by vehicle manufacturers; the benchmark being those supplied in Europe. Minor technical upgrades can be made to Australia’s standards for diesel, biodiesel, ethanol E85 and autogas (LPG) (Hart Energy 2014). Other changes should also be made, including introducing a standard for a B20[1] diesel/biodiesel blend and a developing a standard for petrol rated as 98 RON[2], which is currently assessed against the 95 RON (premium unleaded) standard. As diesel emissions are carcinogenic, Australia should also consider following the lead of Paris, Mexico City, Madrid and Athens, which are banning diesel vehicles from 2025 (United Nations Framework Convention on Climate Change 2016). 

Diesel and other fuels aside, Australia’s petrol quality is particularly problematic. 


The Federal Chamber of Automotive Industries (2108a), representing vehicle manufacturers, has recently stated that EN228[3] quality petrol must be readily available to allow the importation of better vehicles, improve vehicle performance, improve fuel efficiency and reduce noxious and greenhouse gas emissions.

Australia has required that petrol vehicles meet Euro 5 emission standards since 2013 (Department of Infrastructure, Regional Development and Cities 2018). Vehicle manufacturers use Euro 5 quality, i.e. EN228, petrol to certify their vehicles as Euro 5 compliant. So far so good. However Australian petrol is ranked the worst in the OECD[4] (and 73 in the world) based on sulfur content (Stratas Advisors 2018) and does not meet Euro 5 requirements. There is no guarantee that any post-2013 petrol vehicles are meeting Euro 5 emission standards on Australian roads. 

The Euro 5 standard and a proposed more stringent Euro 6 standard are important because they impose limits on vehicular emissions of carbon monoxide, nitrogen oxides, volatile organic compounds and particulate matter. It is well-known that many types of respiratory illnesses (including asthma), heart disease, strokes and cancers would be prevented if emissions were reduced and these standards were met. 

Euro 6 quality petrol must have less than 10 parts per million[5] sulfur (to improve vehicle catalyst performance and reduce emissions), less than 35 percent aromatics (to reduce harmful emissions and combustion chamber deposits) and a minimum 95 RON (for use in fuel efficient, higher compression ratio engines) (Federal Chamber of Automotive Industries 2018b). Australia’s regulated petrol limits compare poorly, with premium 95 RON petrol having a maximum 50 parts per million sulfur and 45 percent aromatics. Worse still is 91 RON (regular unleaded) petrol with up to 150 parts per million sulfur and 45 percent aromatics. Predictably, many vehicle manufacturers do not import their best quality vehicles into Australia. 

Perversely however, many vehicle manufacturers inform new car buyers that their post-2013 vehicles, designed to use Euro 5 quality petrol, can use inferior 91 RON petrol. They do this to compete in a market where cheap, poor quality 91 RON petrol would be used by some motorists regardless of any manufacturer recommendations. The Government must ensure that new motorists use petrol that will allow their vehicles to meet, or have the best chance of meeting, regulated Euro 5 or Euro 6 emission standards.


What should Australia’s petrol quality be? The Australian Institute of Petroleum (2017), representing Australia’s four oil refineries, has insisted that its members could reduce only petrol sulfur content by 2027. Clearly some refineries could do so before 2027, given that other countries (including the USA and New Zealand) have reduced sulfur and aromatics and addressed all other parameters in refined petrol within three years. As the Government prefers that 2027 timeframe, Australia’s petrol quality will remain the worst in the OECD, increased emissions will worsen health outcomes, and Australia will remain an import sanctuary for lesser quality vehicles. Even the Government’s analysis indicates greater net benefits occur with earlier introduction of Euro 6 quality petrol (Department of the Environment 2018b). 

Australia’s four ageing refineries are inefficient. Combined, they produce less than half the refined fuel produced by India’s Jamnagar refinery. Would all four refineries be operating in 2027 anyhow? Governments appreciate that our refineries employ people, but at what cost? The Government’s analysis indicates that if Euro 6 quality petrol were to be supplied, the health benefits would be at least $370 million per year (Department of the Environment 2018b). Australians and their health budget are effectively subsidising local refineries to continue refining poor quality petrol. 

A reduction in petrol’s sulfur content would cost motorists one cent per litre for a few years, if Australia’s multinational refineries choose to pass this cost to motorists. If the Government wanted to support refineries, it could fund refinery upgrades from savings to the health budget. The health benefits would be ongoing, and motorists and the environment could benefit from fuel efficiency improvements. Other matters are manageable, but one significant technical problem remains. Removing sulfur and aromatics from petrol reduces its octane value (Hart Energy 2014).


To enhance octane, organometallic compounds such as lead and MMT, which is available in auto stores, or compounds such as NMA, available in some Australian petrol now, could be used[6]. These compounds are very harmful and damaging to vehicles. All are rejected by vehicle manufacturers and should be prohibited in petrol. While lead has been effectively banned in petrol vehicles on the road since 2002 (a small limit of 5 mg/L allows for residual lead), the Government still permits lead in some racing vehicles. The previous Minister for the Environment decided to phase out leaded racing fuel from July 2017, with no further leaded petrol permitted from 1 July 2019.

Most OECD countries use one of two octane enhancers. MTBE[7] is used in Europe and is the preferred octane enhancer for refineries and vehicle manufacturers. However, it is effectively banned in many US states and elsewhere because it pollutes groundwater when it leaks from storage tanks, even in small concentrations. The last problem Australian farmers need is undrinkable bore water. The alternative is ethanol, which is an excellent octane enhancer. In the USA, 95 percent of all petrol is blended with 10 percent ethanol (US Energy Information Administration 2016). That is, almost all US petrol is E10. Australian refineries do not prefer ethanol, simply because they do not produce it. Ethanol burns cleanly and, if sourced renewably, should appeal to environmentalists, ethanol producers, sugar and related rural industries, north Queensland MPs and people who breathe.

The Australian Automobile Association (2018) is supportive of improvements to fuel quality but is also concerned about the cost effectiveness of fuel quality improvements. The benefits of high octane petrol however, need not come at a substantial cost. E10 petrol is rated as 94 RON and currently cheaper than 91 RON petrol. There are many factors at play here, including ethanol’s higher octane rating and lower energy density compared with petrol, its price competition with petrol and pricing to meet some biofuel mandates. However, with some regulatory tweaks[8] and some deft work at the refinery (easily achievable by our refineries’ excellent chemical engineers), this petrol blend could be increased to 95 RON E10 (with maximum 10 parts per million sulfur and 35 percent aromatics) at a cost comparable to that of 91 RON petrol. Premium Euro 6 quality petrol would then be available at just above a regular unleaded price. Together with the two to eight percent fuel efficiency improvements arising from a minimum 95 RON petrol in the market, there would be reduced emissions and possibly lower net petrol prices for motorists (Asian Clean Fuels Association 2014).


Australia’s choice is simple. The Government seems to want to retain elevated levels of sulfur and aromatics in petrol and sacrifice air quality and people’s health to fund inefficient refineries. Preferably however, the Government, could upgrade the petrol standards to Euro 6 quality, specify an octane enhancer such as ethanol, and allow the market to operate. Petrol could have the parameters that are proposed in Table 1, which differ (after consideration of Australia's unique environmental (including groundwater) conditions) from the European petrol standard mainly in the concentrations of octane enhancing ethers and alcohols. Local refineries could choose to upgrade with or without government assistance, or fuel will be imported, as mostly occurs now. 

There are many options for reduced emissions. NSW and the ACT use mainly imported petrol, and like South Australia, Tasmania and the Northern Territory have no major refineries. If the Australian Government does not significantly improve fuel quality, then those jurisdictions can mandate more stringent fuel quality standards now without affecting refineries in their jurisdictions. Although motorists are paying for vehicles engineered to meet the most stringent Euro emission standards, poor petrol quality means their vehicles do not. Australians should be able to purchase better fuel and with that have greater vehicle choice, better vehicle performance, better fuel efficiency, reduced noxious and greenhouse gas emissions, cleaner air and improved health. 


Table 1. Proposed physical and chemical parameters for petrol compared to the European Union standard (excluding test methods). [Note this table has been adapted and reproduced from the Department of the Environment and Energy (2018b). Proposed parameters for diesel, biodiesel, ethanol E85 and autogas could be taken as those from Option B included in Appendix B of the Department of the Environment and Energy (2018b).]

Petrol parameter

Proposed value of Australian 
petrol parameter a, b

European Union petrol standard (EN228:2012)


Max. 35.0% v/v b

35.0% v/v


Max. 1.00% v/v b

1.00% v/v

Copper corrosion

Class 1 max.
(3 h at 50°C) b

Class 1 
(3 h at 50°C)

Distillation—maximum final boiling point

Max. 210°C b



Max. 10.0% v/v b

10.0% v/v

Tertiary butyl alcohol (TBA)

Max. 0.5% v/v a


Diisopropyl ether (DIPE)

Max. 1% v/v a


Methyl tertiary butyl ether (MTBE)

Max. 1% v/v a

22.0% v/v total ethers

Existent gum (washed)

Max. 5 mg/100 mL b

5 mg/100 mL

Induction period (oxidation stability)

Min. 360 minutes b

360 minutes


Max. 5 mg/L b

5 mg/L

Motor octane number (MON)

91 RON petrol is discontinued b

85.0 c


95 RON petrol (with or without ethanol d): Min. 85.0 b


98 RON petrol (with or without ethanol d): Min. 85.0 f



Max. 18.0% v/v b

18.0% v/v

Oxygen—for petrol without ethanol

Max. 2.7% m/m b

2.7% m/m

Oxygen—for petrol with ethanol

Max. 3.9% m/m a

3.7% m/m


Max. 1.3 mg/L ‘Compounds containing phosphorus shall not be added’ b

Compounds containing phosphorus shall not be added

Research octane number (RON)

91 RON petrol is discontinued b


95 RON petrol (with or without ethanol e): Min. 95.0 b


98 RON petrol (with or without ethanol e): Min. 98.0 f



91 RON petrol is discontinued b

10.0 mg/kg

95 RON petrol: 
Max. 10.0 mg/kg b


98 RON petrol: 
Max. 10.0 mg/kg f


a   Hart Energy, 2014, International fuel quality standards and their implications for Australian standards, report prepared for the Department of the Environment and Energy. Accessed 20 June 2017

b  European petrol standard as described in National Standards Authority of Ireland, 2012, I.S. EN 228:2012 Automotive fuels—unleaded petrol—requirements and test methods, Dublin. 
Purchased 7 June 2016,

c   European Union member states may decide to continue to permit the marketing of gasoline with a minimum MON of 81 and a minimum RON of 91.

d  Petrol blendstocks with less than 85.0/88.0 MON can be used as long as the final blended fuel meets the octane limit.

e   Petrol blendstocks with less than 95.0/98.0 RON can be used as long as the final blended fuel meets the octane limit.

f   European Automobile Manufacturers Association, Alliance of Automobile Manufacturers, Truck and Engine Manufacturers Association & Japan Automobile Manufacturers Association (2013). Worldwide Fuel Charter, 5th edition. Category 5 Unleaded Gasoline Accessed 20 June 2017,





Asian Clean Fuels Association, 2014, JAMA: Towards upgrading regular gasoline to 95 RON

Australian Automobile Association, 2018, AAA response to Better fuel for cleaner air, Draft regulation impact statement

Australian Institute of Petroleum, 2017, AIP submission to Department of Environment and Energy

Department of Infrastructure, Regional Development and Cities, 2018, Summary of emission requirements for new petrol passenger cars in Australia

Department of the Environment and Energy, 2018a, Fuel Quality Standards

Department of the Environment and Energy, 2018b, Better fuel for cleaner air: regulation impact statement, Commonwealth of Australia 2018,

Federal Chamber of Automotive Industries, 2018a, FCAI Response to Better fuel for cleaner air Draft regulation impact statement

Federal Chamber of Automotive Industries, 2018b, Fuel Quality and Emissions, Actions for Vehicle Emission Standards,

Hart Energy, 2014, Report to the Department of the Environment, International Fuel Quality Standards and Their Implications for Australian Standards

Stratas Advisors, 2018, 14 countries and territory state move up in top 100 ranking on gasoline sulfur limits

United Nations Framework Convention on Climate Change, 2016, Paris, Mexico City, Madrid, Athens to Remove Diesel Vehicles by 2025

US Energy Information Administration, 2016, Almost all U.S. gasoline is blended with 10% ethanol




[1]   B20 fuel has more than 5 percent and less than or equal to 20 percent biodiesel in diesel. 

[2]   RON refers to the research octane number and is one measure of petrol’s ‘octane rating’.

[3]  EN228 is the European Standard specifying the physical and chemical requirements and test methods for unleaded petrol, see Similarly, EN590 is the standard specifying the physical and chemical requirements and test methods for automotive diesel. 

[4]   OECD is the Organisation for Economic Cooperation and Development, an intergovernmental economic organisation with 36 members.

[5]   A concentration of one part per million is equivalent to 1 mg/kg.

[6]   Organometallic compounds contain at least one bond between a carbon atom of an organic compound and a metal. Lead refers to tetraethyllead, MMT is methylcyclopentadienyl manganese tricarbonylandNMA is N-methylaniline.

[7]   MTBE is methyl tert-butyl ether (2-methoxy-2-methylpropane).

[8]   Regulatory changes to permit the use of blendstocks for oxygenate blending would allow higher octane ratings for a blended fuel to be met at a cheaper cost.


David Swanton is an ethicist, scientist and director of Ethical Rights .