Output Results

InMAP calculates the changes in concentrations of PM2.5, its components, and its precursor pollutants caused by a scenario of changes in emissions specified by a user.

It also allows to the user to use the quantities that are natively calculated by the model (listed here) as building blocks to create other outputs using equations. This behavior is specified with the OutputVariable configuration variable.

OutputVariables

The OutputVariables configuration variable allows users to use equations to create their own outputs. Each equation consists of a new output variable name specified on the left, followed by an equals sign and an expression defining the new variable based on already-existing variables on the right.

For example, if we wanted to output a variable which was twice the average wind speed, we could specify:

[OutputVariables]
WindSpeed2 = "WindSpeed * 2"

It is important to note that variable names must be 11 characters long or less.

For a more useful output, we could specify population-weighted concentration:

[OutputVariables]
TotalPM25 = "PrimaryPM25 + pNH4 + pSO4 + pNO3 + SOA"
PopWtd = "TotalPM25 * TotalPop / sum(TotalPop)"

Note that equations can include variables that are defined in another equation. There are also some built-in equations, such as sum(). See the API documentation for a complete list of built-in functions.

We can also calculate differences in population-weighted concentrations among race-ethnicity groups:

[OutputVariables]
TotalPM25 = "PrimaryPM25 + pNH4 + pSO4 + pNO3 + SOA"
whiteExp = "TotalPM25 * WhiteNoLat / sum(WhiteNoLat)"
blackExp = "TotalPM25 * Black / sum(Black)"
diff = sum(whiteExp - blackExp)

Or we can calculate health impacts from PM2.5 exposure, for example using a Cox proportional hazards model and assuming a 6% increase in overall mortality for every 10 μg/m³ increase in PM2.5 concentration (based on the work of Krewski and colleagues, 2009):

[OutputVariables]
TotalPM25 = "PrimaryPM25 + pNH4 + pSO4 + pNO3 + SOA"
deaths = "(exp(log(1.06)/10 * TotalPM25) - 1) * TotalPop * allcause / 100000"

Although OutputVariables can be specified as an environment variable or command-line argument, it typically works best to specify them within a configuration file. If a user wants to specify them as a environment variable or command-line argument, however, the entire set of variables must be converted to JSON format. For example, the example above as a command-line argument would be:

--OutputVariables="{\"TotalPM25\":\"PrimaryPM25 + pNH4 + pSO4 + pNO3 + SOA\",\"deaths\":\"(exp(log(1.06)/10 * TotalPM25) - 1) * TotalPop * allcause / 100000\"}\n"