Vehicle emissions are a significant environmental concern, impacting air quality and public health. These emissions are broadly categorized into two main types: greenhouse gas emissions and air pollutant emissions, each with distinct consequences.
Greenhouse gas emissions, primarily carbon dioxide (CO2), contribute to climate change by trapping solar heat within the Earth’s atmosphere – the well-known ‘greenhouse effect’. Motor vehicles are a notable source of CO2, making them a key factor in global warming.
Air pollutant emissions from vehicle exhausts include harmful substances such as carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), and volatile organic compounds (VOCs). These pollutants are responsible for smog formation and pose serious health risks, including respiratory illnesses, heart disease, and cancer.
Greenhouse Gas Emissions: Australia’s Contribution and Standards
Motor vehicle exhaust is a major contributor to greenhouse gases, exacerbating climate change. Carbon dioxide (CO2) is the most prevalent greenhouse gas emitted by vehicles, alongside nitrous oxide and methane. In Australia, light vehicles account for approximately 11% of the nation’s total greenhouse gas emissions.
Detailed information on Australia’s greenhouse gas emissions is available through Australia’s National Greenhouse Accounts, maintained by the Department of Climate Change, Energy, the Environment and Water. This resource offers comprehensive data and insights into emission sources across the country.
The Green Vehicle Guide (GVG) utilizes CO2 emission figures to rate vehicle environmental performance. A higher CO2 rating on the GVG indicates greater carbon dioxide output from a vehicle’s tailpipe. In Australia, all new vehicle models under 3.5 tonnes gross vehicle mass are mandated to undergo fuel consumption and CO2 emissions testing before being offered for sale.
These tests yield three key values: ‘combined’, ‘urban’ (low speed), and ‘extra-urban’ (higher speed) fuel consumption and CO2 emissions. The ‘combined’ CO2 value is the benchmark used for vehicle ranking on the GVG website. This information is also prominently displayed on the Fuel Consumption Label affixed to the windscreen of new vehicles, providing consumers with transparent emissions data. Generally, vehicles with higher fuel consumption rates will correspondingly produce greater CO2 emissions.
In 2019, the average new light vehicle sold in Australia emitted 181 grams of CO2 per kilometer (g/km). The National Transport Commission has estimated that significant reductions in CO2 emissions from new light vehicles – up to a certain percentage – could be achieved if Australian consumers opted for the most fuel-efficient vehicle within each class. This highlights the potential for consumer choice to drive down vehicle-related greenhouse gas emissions.
Air Pollutant Emissions: Euro Standards and Australian Regulations
Air pollutants pose a direct threat to human health, contributing to smog and respiratory problems. The Department of Climate Change, Energy, the Environment and Water provides extensive resources on the health impacts of air pollution.
Motor vehicles remain a primary source of air pollutants, particularly in densely trafficked areas. However, advancements in vehicle technology have led to cleaner exhaust systems, significantly reducing air pollutant emissions in many newer models.
Vehicle emission standards, often referred to as ‘Euro levels’, define the permissible limits for air pollutant emissions. Vehicles meeting higher Euro standards exhibit lower air pollutant emissions compared to those adhering to older, less stringent standards. The air pollution standard or ‘Euro’ standard that a vehicle model meets in Australia is typically detailed in vehicle specifications and regulatory information.
Currently, the minimum air pollution standard for new light vehicles in Australia is ADR 79/04, which is based on the internationally recognized ‘Euro 5’ standard. However, many vehicles sold in Australia already comply with the more rigorous Euro 6 standards, demonstrating a move towards cleaner vehicle technology, even exceeding the minimum Australian requirements which are aligned with Australia to Euro standards progression.
Specifically, Euro 6 diesel vehicles are engineered to emit significantly less oxides of nitrogen (NOx) compared to Euro 5 diesel vehicles. Similarly, Euro 6 petrol vehicles achieve lower fine particle emissions than their Euro 5 counterparts.
Australia is set to further enhance its emission standards with the introduction of three new Australian Design Rules (ADRs) based on the Euro 6d standards for light vehicles (cars, SUVs, and light commercial vehicles). These will be phased in for:
- Newly approved light vehicle models first supplied to Australia from 1 December 2025.
- All new light vehicles supplied to Australia on or after 1 July 2028.
These updated ADRs will be implemented in conjunction with improvements to fuel quality standards, specifically targeting a reduction in aromatics in ‘premium unleaded’ (95RON) petrol. The final text of these new ADRs is being finalized in consultation with key stakeholders. Further information on fuel quality standards is available from the Department of Climate Change, Energy, the Environment and Water, highlighting the interconnected approach to reducing vehicle emissions in Australia, drawing upon and adapting Australia to Euro standards.
The Australian Government is also actively considering the fuel consumption labelling requirements that will apply to vehicles meeting these new, more stringent ADRs, ensuring ongoing transparency and consumer information regarding vehicle emissions and fuel efficiency.
