Vehicular Air Pollution Information System (VAPIS)

Update: January 2015


Download the VAPIS 1.01 tool, brochure, operational manual, and the working paper on four ways to build vehicular emissions inventory (see SIM 02-2008).

VAPIS 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.

The basic equation utilized for these calculations and a snapshot of the inputs page, data from which is propagated through the equation, are displayed below.



A combination of graphs generated by the VAPIS tool are presented here. 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 (right-bottom-panel in the above table) where examples like reduced VKTs, new retirement policies, new emission standards, can be analyzed and visualized immediately.

For the user’s benefit, a fleet average emission factors are generated (which should be used with discretion) and presented below.


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

1United States Environmental Protection Agency’s AP-42 Handbook

2MOVES (Motor Vehicle Emission Simulator)

3Emission Factor Database by National Atmospheric Emissions Inventory of UK

4Air Pollutant Inventory Program of SEI

5Emission Factor Database by Central Pollution Control Board of India

6Emission Factor Database by DIESEL Program of PCD Thailand & the World Bank

7Emissions Analysis Tool by ICLEI

8COPERT by European Environmental Agency

9IPCC Guidelines for GHG


11TREMOVE for European Countries

12EMEP Corinair Emissions Inventory Guidebook

13Transport Emissions Analysis for Hanoi by WRI/EMBARQ



*** The tools and documents are free to download. However, please cite appropriately. Feedback and suggestions are welcome.

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



Publications and support material using the VAPIS and SIM-air methodology

Evolution of On-road Vehicle Exhaust Emissions in Delhi
Journal article in Atmospheric Environment (2015) Download
[Press cover in]

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]
[Support material from the study]
[Press cover in Times of India]
[Press cover in Hindustan Times]