air pollution simulation

[mchp316]

Hi Tim,

I am a beginner. I am using ENVi-met for air pollution simulation. I watched all the videos and set up the simulation followed the videos. However, I cannot get any result of pollutions. I have a full version. The species I simulated were PM2.5, PM 10, NO, NO2, O3. I did not define a user-defined pollutant. Is it necessary to define them? But, I did not find where to define them in <sources>.

I am looking forward to hearing from you. Thanks very much.
Chunping

[Tim]

Hi Chunping,

It you followed all necessary steps, it should work properly. Why did you not find the user-defined emission profile? You need to set the values in the DBManager, then digitize the new source in your model area and afterwards activate a simulation with MultiPollutants in the ENVIguide.

Best regards,
Tim

[MariaH]

Hi Tim,
one more question concerning this topic. In the Envi-Guide (Intermediate mode) I can do the settings for the "pollutant dispersion" --> at the bottom "Chemical Species or type of pollutant" --> I chose "PM" and then there are additional settings for particles --> particle diameter and density (g/cm³). Does it mean the density especially of the pollution coming from the source or the general density of the pollution particles in the whole ambient air?

Thanks in advance!

Maria

[Tim]

Hi Maria,

The pollutant emission profile coming from the source can be edited in the DBManager. The particle density in the ENVIguide refers to the density of a single pollution particle.

Best regards,
Tim

[MariaH]

okay, thanks!

[mchp316]

Hi Tim,

I conducted the simulation again, I got PM2.5 concentration this time. However, the results of NO/NO2/O3 seem not good. Can you help me out here? The model settings and result of PM2.5 and NO are attached.
Moreover, it took almost 2 days to finish thia 5-hour simulation in the latest version. Is there any possible to make it faster?

All the best,
Chunping

defined source in database

source in model settings
simulation settings




results

[Tim]

Hi Chunping,

Unfortunately, the image upload did not work correctly for your post, they are not visible. Why do you think that they look bad? We had an issue with sources calculations causing strange patterns in concentration. The bugfix version is only available since a few days from our homepage. You may try it again with that version.
Pollutant simulations are more complicated and need thus more time. If you ran them in multicore already, you cannot make it faster anymore.

Best regards,
Tim

[MariaH]

Hi,

I still have problems with my pollution settings. Some settings in the Envi-Guide cause errors in my simulation.
When I choose the options "multi pollutant mode" and "dispersion only" and user-defined pollutant "none", I get the following error in the simulation report after checking:

**Error: Cannot identify the type of source**
**Valid types are PM, CO, CO2, SO2, O3, NO, NO2, H2O2, NH3 and C5H8**
**---Disabling all sources---**

Furthermore when I start the simulation I get the error "floating point devision by zero" right at the beginning.

But when I choose a user-defined pollutant (that isn't already included in the 5 pre-defined pollutants), like SO2, the error disappears. But why do I have to specify the user-definded pollution (even if there is the option <none>) and does it affect the simulation time because this extra pollution has to be simulated additionally?

Thanks for helping!

Best regards
Maria

[Tim]

Hi Maria,

Pollutant simulations began with the User emission profile. Later, the other pollutants were added. Pollutant simulations still await a user emittant per default. Simply enter any name, the profile itself can simply be filled with 0. It does not affect the simulation time, all pollutants are simulated anyway if MultiPollutant mode is activated.
However, you are right it should not be an option then.

Best regards,
Tim