Vehicular Air Pollution Information System (VAPIS)

Last updated: January 2015


Vehicle Exhaust EmissionsVehicle exhaust emissions have always been considered the most important (and often the majority) source of air pollution in the cities. There are many ways to build an emissions inventory for this sector, depending on the level of information available. We summarized them into 4 ways and explained in this working paper (see SIM 02-2008).

VAPIS tool, one of the integral parts of the SIM-air family of tools, is an user friendly spreadsheet based tool, designed to quickly analyze emission trends for a single vehicular category for a single pollutant. This tool allows the user to start with the basic information on vehicular numbers, growth rates, age splits, kilometers traveled per day, average retirement age, and emission factors, and establish the vehicular number and emission trends for a period of 30 years, by age group.

Download the VAPIS 1.01 tool, operational manual, and the working paper on four ways to build vehicular emissions inventory .

The fundamental equation utilized in VAPIS is the following

Vehicle Exhaust Emissions

Snapshots what the inputs and results look like from using this equation are illustrated in the brochure,. Being an spreadsheet based tool, the user will be able to plug and play with the parameters for intermediate years and note the changes immediately. The VAPIS tool also provides a step to conduct scenario analysis and compare the results, where examples like reduced vehicle km traveled (VKTs), new retirement policies, new emission standards, can be analyzed and visualized immediately. For the user’s benefit, an example fleet average emission factors are included in the brochure.

Not all the cities are equipped with emission testing facilities, which cost millions for establishment, operation, and maintenance. Existing emission databases include:

  1. United States Environmental Protection Agency’s AP-42 Handbook
  2. MOVES (Motor Vehicle Emission Simulator)
  3. Emission Factor Database by National Atmospheric Emissions Inventory of UK
  4. Air Pollutant Inventory Program of SEI
  5. Emission Factor Database by Central Pollution Control Board of India
  6. Emission Factor Database by DIESEL Program of PCD Thailand & the World Bank
  7. Emissions Analysis Tool by ICLEI
  8. COPERT by European Environmental Agency
  9. IPCC Guidelines for GHG
  10. GAINS of IIASA
  11. TREMOVE for European Countries
  12. EMEP Corinair Emissions Inventory Guidebook
  13. Transport Emissions Analysis for Hanoi by WRI/EMBARQ

*** The tools and documents are free. Please cite appropriately when the tools and the working papers are used. Feedback and suggestions are welcome.

*** Below are some videos explaining the equations and data resources utilized in the VAPIS tools

Video 1: Overview of the VAPIS tool and operations

Video 2: Database of emission factors

Publications and support material on vehicle exhaust emissions (more here)

Air Pollution knowledge Assessments (APnA) for 20 Indian cities
Journal article in Urban Climate (2019) Download (2nd most downloaded as of 31st May 2019)
[Repository for these cities and more]

Evolution of on-road vehicle exhaust emissions in Delhi
Journal article in Atmospheric Environment (2015) Download
[Press cover in]
[Supplementary Material – Fleet average emission factors for 1990]
[Supplementary Material – Fleet average emission factors for 2000]
[Supplementary Material – Fleet average emission factors for 2030]
[Supplementary Material – Annual emissions, modal shares, and fuel shares for 1990 to 2030]

Role of urban growth, technology, and judicial interventions on vehicle exhaust emissions in Delhi for 1991-2014 and 2014-2030 periods
Journal article in Environment Development (2015) Download

Benchmarking vehicle and passenger travel characteristics in Delhi for on-road emissions analysis
Journal article in Travel Behaviour and Society (2015) Download
[Press cover in Times of India]
[Press cover in]

Re-fueling road transport for better air quality in India
Journal article in Energy Policy (2014) Download
[Study results are included in the Planning Commission’s National Transport Policy Committee report]
[Supporting material from the study]
[Press cover in Times of India]
[Press cover in Hindustan Times]