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Health Impacts of Air Pollution: A Tool to 
Understand the Consequences

Christopher Tessum | Jason Hill | Julian Marshall

Publication: Tessum, C. W.; Hill, J. D.; Marshall, J. D. InMAP: A model for air pollution interventions.  PLoS ONE 2017, 12 (4), e0176131 DOI: 10.1371/journal.pone.0176131.

What is            ?


InMAP is a recently developed model which offers a new approach to estimating the human health impacts caused by air pollutant emissions and how those impacts are distributed among different groups of people. InMAP is:



Designed to be used by a wide range of professionals concerned with how air pollution affects health.



One tool to perform an entire health impact analysis.



Runs on a desktop computer instead of a supercomputer as usually required by comprehensive air quality models.


BIG   + SMALL - 

Able to simultaneously track within-city differences in impacts as well as impacts thousands of miles from the emissions source, unlike other simplified models.



Meets published criteria for air quality model predictive performance.


Long range transport

Secondary pollutant formation

Many pollutants

Many sources

InMap Images-18-15.png

High spatial resolution

Computational efficiency


InMAP allows users to explore the consequences of emissions changes at a high resolution in a simple and computationally inexpensive way.

Why use            ?

Because InMAP is a reduced complexity air quality model, it may not be the perfect tool for every job. However, InMAP is well suited for many situations, such as:


  • Projects that require many model runs, such as those that include scenario or uncertainty assessment.

  • Projects that would benefit from the combination of a large spatial resolution an high spatial resolution compared to what is available in other models.

  • Projects interested in investigation of environmental injustice or equity issues.

  • Projects that do not have access to the time, expertise, or resources required to run comprehensive chemical transport models.

Meets published criteria for air quality model predictive performance.



InMAP  estimates changes in human PM2.5 exposure caused by the input emissions using census data

InMap Images-18-16-16-15.png

InMap reads annual total emissions from an arbitrary shapefile and allocates them to the model grid


InMAP methodology


InMAP calculates how different demographic groups are exposed to PM2.5 even when the groups live in adjacent neighborhoods.

Optionally, health damages can be converted to economic damages using a  Value of Statistical Life metric

Using epidemiological concentration-response functions, InMAP calculates the health impacts of the emissions.

economic damage

environmental justice

health impacts


InMAP  calculates annual average changes in PM2.5 concentrations caused by the input emissions


in Action


This animation shows an InMAP model simulation. The model runs until it converges on a steady-state solution, adjusting the size of the grid cells as it runs.



Play Video

How is            new? 

InMAP includes several features that together enable analyses to be done in InMAP that cannot be done or are much more difficult in other models. These features include:

  • A variable-resolution computational grid, which allows the model to save time by focusing computational resources in areas where extra spatial detail is most useful.

  • Simplified chemistry and physics parameterizations that save computational time while still creating a mechanistic representation of the atmosphere.

  • Health impact calculations built into the model to avoid the need for a separate tool.

  • A software framework that allows the model to run on most types of computers.

  • Input and output files in the widely-used shapefile    format.

How do I use           ?

The InMAP model is completely open-source. It is available to download. Instructions for its use are on the same page.

Join the   InMAP users' Google Group for news and discussions related to the model.

Additional questions? Contact us at

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