Emissions To Air
Although emissions per passenger journey from buses are much lower than cars, our exhaust emissions do impact on air quality. We continue to significantly reduce these emissions by investing in new engines, fitting additional emission control technology, such as catalytic converters and particulate traps, and ensuring that our maintenance and fleet management programmes are effectively managed.
EURO III engines now make up 31% of the fleet an increase of 6% since last year. We are now introducing EURO IV engines which will further reduce emissions.
We calculate the emissions from our buses on an annual basis using emission factors published in the National Atmospheric Emissions Inventory (NAEI) database www.naei.org.uk (link opens in a new window). This contains emission factors for each of the pollutants reported for all Euro engine types and pre Euro engines. Emission factors are adjusted for average operating speeds and vehicle mileage within each operating company.
| Ongoing investment in new vehicles has achieved the following emissions reductions since 2001. | ||
|---|---|---|
| Pollutant | Percentage reduction | Tonnage reduction |
| Particulates | 64% | 306 |
| Nitric oxides | 38% | 2,883 |
| Carbon monoxide | 67% | 2,474 |
| Hydrocarbons | 62% | 800 |
The graph shows the rapid increase in buses with Euro 3 engines since 2002 and the corresponding decline in pre Euro models. Buses with Euro 2 and Euro 3 engines are now the main types in the First fleet.
