Best case for regulated emissions is zero emissions (= 100% in the above chart) and the worst case is a Euro 3 car (0% in the chart). The graph for evaporation of hydrocarbons indicates how many percent better the car is compared to current European emission legislation.
The last graph shows the CO2 -emissions compared to the Volvo car that emits most and least.
Useful Life
A car generates most of its environmental impact during its useful life. Driving a car powered by current technology (i.e. a combustion engine burning a fossil fuel) causes environmental pollutants to be emitted to the atmosphere. It is generally considered that the three most significant forms of environmental impact attributable to a car in service are legally controlled emissions, evaporation of hydrocarbons and carbon dioxide emissions. These, therefore, are the indicators chosen in this area. A particulate emissions indicator is also included for diesel engines.
Abbreviations for Emission Levels
EURO3
For new types from 2000-01-01, all types from 2001-01-01
EURO4
For new types from 2005-01-01, all types from 2006-01-01
Exhaust Gases Cause Major Environmental Problems
The highest proportion of the environmental impact, local and regional, generated by petrol-engined vehicles in traffic is attributable to emissions of carbon monoxide, hydrocarbons and nitrogen oxides from the exhaust gases. These emissions may be harmful in high concentrations under unfavourable traffic and climatic conditions, for example when an inversion is present. When exposed to sunlight in hot weather, hydrocarbons and nitrogen oxides combine to form ground-level ozone, which not only damages vegetation, but causes respiratory ailments in humans, especially children.
Nitrogen oxides also contribute to eutrophication (an excess of nutrients in lakes and rivers which favours plant growth and deprives aquatic life of oxygen) and acidification. The emissions have fallen by up to 99% since the three-way catalytic converter was introduced by Volvo Cars in the 1970s.
These three pollutants are controlled by legislation in almost every country in the world. Statutory limits are lowest in California, where the strictest provisions are contained in the ZEV (Zero Emission Vehicle) standard¹.
The quantity of particulates emitted by diesel engines is also controlled. A particulate filter can be used to trap the particulates and burn them at intervals when the filter is regenerated. The filter reduces particulate emissions by approximately 95%. All of our engine variants comply with the provisions of the European Euro 4 standard, which are comparable to the Californian ULEV (Ultra Low Emission Vehicle) requirements. Volvo Cars offer certain drivetrains that meet the expected Euro 5 level of tail pipe emission requirements. Pls contact your local dealer for more information.
All Volvo engines are equipped with European On-Board Diagnostics (EOBD), which indicate when the emission levels are too high. In this event, the car should be brought to a Volvo dealer for attention. Volvo's diesel engines were also equipped with EOBD in 2003. Variants with a particulate filter have been introduced in most of our models.
Best and Worst Cases
The best case is represented by a car which emits none of these pollutants (Zero Emission Vehicle).
The worst case is represented by a car complying with Euro 3, equivalent to 2.3 g/km of carbon monoxide, and 0.20 g/km of hydrocarbons plus nitrogen oxides². Euro 4 statutory limits are intermediate to the best and worst case. Diesel engines must comply with limits of 0.64 g/km for carbon monoxide and 0.56 g/km for hydrocarbons plus nitrogen oxides to comply with Euro 3.
Footnotes:
¹ .California Code of Regulations Title 13.
². EU Directive 70/220 EC, as amended.
Evaporation of Hydrocarbons
The exhaust pipe is not the only source of hydrocarbon emissions from a car. Petrol evaporates when refuelling, when the engine is hot and during hot weather, causing emissions which may be as hazardous to human health and the environment as the exhaust emissions.
Evaporation Control Systems
All Volvo cars are now fitted with systems, including carbon canisters, to reduce evaporative emissions from the fuel system.
Best and Worst Cases
The best case is represented by zero evaporation under test.
The worst case corresponds to the limit (2 g/test) specified in current European legislation.¹
Particulate Emission (Diesel Only)
Particulate emissions from diesels are higher than from petrol engines; however, fuel evaporation is considerably lower. Therefore, it is more important to measure the particulate emissions rather than the evaporation from the car.
Best and Worst Cases
The best case is when no particulate matter whatever is emitted.
The worst case corresponds to the limit (0.05 g/km) specified in current European legislation¹.
Comparison Notice
Please note that diesel engines and petrol engines should be compared in terms of their common indicators only.
A comparison cannot be based on essentially different indicators. The indicators are not designed to answer questions like "is a 70%-level emission of particulates better than a 60%-level evaporation of hydrocarbons?"
For this reason, comparisons between diesel and petrol engines in terms of their propellant specific indicators used in this EPI, that is evaporation of hydrocarbons in the case of petrol engines and particulate emissions in the case of diesel engines, are misleading.
Footnote:
¹ EU Directive 70/220 EC, as amended
Carbon Dioxide Emissions
Carbon dioxide emissions contribute to global climate change. The carbon dioxide emissions from a car are related to its fuel consumption.
Fuel Consumption Reduced
Volvo cars are competitive in terms of fuel consumption. For instance, the Volvo S40 1.6 Diesel (manual) consumes 4.9 l/100 km. This has been achieved by introducing continual refinements, such as improved engine management systems, and reducing engine friction. Other power train components have also been improved.
Best and Worst Cases
The best case is 4.9 l/100 km1 for S40 Diesel (manual) equivalent to 129 g/km CO2, and the worst case figures are 13.5 l/100 km1 for XC90 V8 automatic equivalent 322 g/km CO2.
Footnote:
1 Combined fuel consumption figure