<p>The <code>POLLUTID</code> key is used to specify some regular options.</p>
<p>Some examples:</p>
<ul>
<li><code>PM2.5</code> can only evaluate averages greater than 24 hours (if you try to generate hourly averages it throws an error).</li>
<li><code>NO2</code> forces the use of options to simulate the conversion of NO<sub>x</sub> to NO<sub>2</sub>.</li>
<li><code>SO2</code> triggers the use of a 4-hour half-life for SO<sub>2</sub> decay in urban zones.</li>
</ul>
<p>All pollutants (gases and particles) are treated similarly, regardless of their weight or molecular density.</p>

CC BY-SA 4.0
2021-03-19T02:35:03.780Z
2021-03-21T08:47:40.660Z
2021-03-21T08:47:40.660Z
Marco
<p>Since I use OTHER as a pollutant ID, are there some parameters I could specify in order to get better results for dispersion of substance I am trying to model? eg. molecular weight or density?</p>

<models><air-pollution><pollution>
How can I specifiy a substance in AERMOD?
kavej
# How can I specifiy a substance in AERMOD?

(Asked by: username_0 on 2020-06-09)

Since I use OTHER as a pollutant ID, are there some parameters I could specify in order to get better results for dispersion of substance I am trying to model? eg. molecular weight or density?

**Tags:** models, air-pollution, pollution


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## 1 answers

### Answer by username_1 on 2021-03-19. Score: 2

The `POLLUTID` key is used to specify some regular options.

Some examples:

* `PM2.5` can only evaluate averages greater than 24 hours (if you try to generate hourly averages it throws an error).
* `NO2` forces the use of options to simulate the conversion of NOx to NO2.
* `SO2` triggers the use of a 4-hour half-life for SO2 decay in urban zones.

All pollutants (gases and particles) are treated similarly, regardless of their weight or molecular density.


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