Tackling urban air quality improvement with zero emission buses

In collaboration with partners, UN Environment is providing direct support to twenty major cities in Asia, Latin America and Africa to prepare roadmaps for low emission public transport, including the introduction of electric buses.

Urban buses account for approximately 25% of the black carbon emitted by the transportation sector. Urban bus activity is predicted to increase by nearly 50% by 2030; this will translate into an estimated additional 26,000 tons of black carbon

UN Environment seeks to address the significant emissions and public health burden of urban bus fleets by supporting soot-free engine technologies, including electric engines. This will impact a combined 234 million people, preventing approximately 3,700 premature deaths and as much as 6.6 MMT CO2e (GWP-20) by 2030 (or 1.7 MMT CO2e GWP-100).

Together with the International Council on Clean Transportation (ICCT) and regional partners, UN Environment provides technical and policy support to identify barriers, undertake activities that can remove such barriers, and support the subsequent design and adoption of a public commitment to cleaner buses.
The partners in this endeavor have set out a range of activities to be implemented over a 2-year period that are aimed at securing commitments from city officials to shift to cleaner buses, and supporting the implementation of these commitments.

The dedicated strategy consists of the following elements:

  • Inform, motivate, and secure a public commitment from city officials to shift to soot-free urban bus fleets;
  • Provide implementation support;
  • Establish an industry partnership with engine manufacturers and suppliers of commercially available soot-free engines, including electric versions;
  • Develop an urban bus fleet database; and
  • Report back to the Heavy Duty Diesel Initiative of the Climate and Clean Air Coalition on opportunities to expand the deployment of soot-free engines.

Clean bus fleet pilot cities include:

  1. Mexico, Mexico
  2. Sao Paulo, Brazil
  3. Buenos Aires, Argentina
  4. Istanbul, Turkey
  5. Sydney, Australia
  6. Santiago, Chile

The wider network of 14 cities to promote clean bus fleets include:

  1. Manila, Philippines
  2. Bangkok, Thailand
  3. Lima, Peru
  4. Bogota, Colombia
  5. Dar es Salaam, Tanzania
  6. Johannesburg, South Africa
  7. Nairobi, Kenya
  8. Casablanca, Morocco
  9. Jakarta, Indonesia
  10. Dhaka, Bangladesh
  11. Lagos, Nigeria
  12. Abidjan, Cote d’Ivoire
  13. Accra, Ghana
  14. Addis Ababa, Ethiopia

The eMob Calculator to estimate costs and benefits of a large scale deployment of electric buses

UN Environment developed the eMob Calculator for buses, which enables the user to assess the potential of electric and other low emission buses (such as Euro 6 and CNG buses) to reduce energy use, CO2 and air pollutant emissions as well as costs until the year 2050. The tool can be used to perform cost-benefit analysis on a national as well a city 

An assessment of a business as usual scenario as well as an eMob scenario for the global heavy duty bus fleet indicates that a profound shift to zero and low emission battery electric, hybrid and CNG buses could save approximately 1.4 billion tons of CO2 and almost 30 million tons of particulate matter between now and 2050.

Global vehicle stock by technology as well as CO2 and PM emissions of buses for a business as usual and the eMob scenario

Global vehicle stock by technology as well as CO2 and PM emissions of buses for a business as usual and the eMob scenario


The Climate and Clean Air Coalition

The Climate and Clean Air Coalition (CCAC) has been founded as a partnership of governments, intergovernmental organizations, businesses, scientific institutions and civil society organizations to protect the climate and to improve air quality through actions to reduce short-lived climate pollutants.

UN Environment is one of about 100 partners and also hosts the secretariat.

The CCAC founded the Heavy-Duty Diesel Vehicles and Engines Initiative, which works towards major reductions in black carbon through adoption of clean fuel and vehicle regulations and supporting policies. Diesel engines in all economic sectors are in the focus. The Sootfree Buses Project under the Heavy-Duty Diesel Vehicles and Engines Initiative works towards accelerating the global transition to soot-free bus engine technology. The promotion of electric buses is a pillar of the programmeme.