Vehicle emissions refer to the substances expelled from a car’s exhaust system as a byproduct of burning fuel. These emissions have significant consequences for both the environment and human health, broadly categorized into greenhouse gas emissions and air pollutant emissions.
Greenhouse Gas Emissions: Trapping Heat and Driving Climate Change
Greenhouse gas emissions (GGE) are gases that trap heat in the Earth’s atmosphere, leading to a phenomenon known as the ‘greenhouse effect’. This effect is a primary driver of climate change and global warming. Carbon dioxide (CO2) stands out as the most prevalent greenhouse gas emitted by vehicles. While CO2 is the major concern, motor vehicles also release other greenhouse gases such as nitrous oxide and methane, further contributing to climate change.
In Australia, light vehicles are responsible for a notable portion of the nation’s overall greenhouse gas emissions. For detailed data and insights into greenhouse gas emissions in Australia, the Australia’s National Greenhouse Accounts maintained by the Department of Climate Change, Energy, the Environment and Water, serves as a comprehensive resource.
The Green Vehicle Guide (GVG) utilizes CO2 emission figures as a key metric for evaluating and ranking vehicles based on their environmental performance. A higher CO2 emission value on the GVG indicates a greater amount of carbon dioxide released per kilometer driven. In Australia, all new car models under 3.5 tonnes gross vehicle mass are mandated to undergo fuel consumption and CO2 emissions testing before being available for sale.
This testing process yields three distinct fuel consumption and CO2 emission figures: ‘combined’, ‘urban’, and ‘extra-urban’. The ‘combined’ CO2 value is the standard metric used for vehicle ranking on the GVG website and is also prominently displayed on the Fuel Consumption Label affixed to the windscreen of new vehicles. It’s a general rule that vehicles with higher fuel consumption rates typically produce higher CO2 emissions.
Statistics from 2019 reveal that the average new light vehicle sold in Australia emitted 181 grams of CO2 per kilometer (g/km). The National Transport Commission suggests that if consumers opted for the most fuel-efficient vehicle within each class, CO2 emissions from new light vehicles could be significantly reduced.
Air Pollutant Emissions: Harming Air Quality and Human Health
Air pollutant emissions are another critical category of vehicle emissions, directly impacting air quality and posing risks to human health. For in-depth information on the health impacts of air pollution, resources are available from the Department of Climate Change, Energy, the Environment and Water.
Motor vehicles remain a significant contributor to air pollution, particularly in densely trafficked areas. However, advancements in vehicle technology have led to cleaner exhaust systems in many modern cars, resulting in reduced air pollutant emissions compared to older models.
Vehicles adhering to higher air pollution standards, often denoted by ‘Euro levels’, produce fewer air pollutants. The ‘Euro’ standard achieved by a vehicle model in Australia is usually detailed in the vehicle’s specifications. Currently, the minimum emission standard for new light vehicles in Australia is ADR 79/04, aligning with the international ‘Euro 5’ standard. Many vehicles sold in Australia already meet the more stringent Euro 6 standards prevalent in other regions.
Notably, Euro 6 diesel vehicles emit lower levels of oxides of nitrogen (NOx) compared to Euro 5 diesel vehicles, and Euro 6 petrol vehicles produce fewer fine particles than their Euro 5 counterparts.
Australia is set to adopt three new Australian Design Rules (ADRs) based on the Euro 6d standards for light vehicles, including cars, SUVs, and light commercial vehicles, to be implemented in phases:
- For newly approved light vehicle models introduced to Australia from December 1, 2025.
- For all new light vehicles supplied to Australia on or after July 1, 2028.
These updated ADRs will be rolled out in conjunction with enhanced fuel quality standards aimed at reducing aromatics in ‘premium unleaded’ (95RON) petrol. Further details regarding fuel quality standards can be found from the Department of Climate Change, Energy, the Environment and Water.
The government is also actively evaluating fuel consumption labeling requirements for vehicles complying with these new ADRs, indicating a continued commitment to transparency and consumer awareness regarding vehicle emissions and fuel efficiency.
In conclusion, understanding car emissions, both greenhouse gases and air pollutants, is crucial for addressing environmental concerns and safeguarding public health. Regulations and advancements in vehicle technology are continuously working towards reducing these emissions and promoting cleaner transportation options.
