Background level.

All around LEONARDO 4 (and previous 2014)
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Broni
Posts: 4
Joined: Sat Aug 10, 2019 10:20 am

Background level.

Post by Broni »

Hello,
I have a pleasure to use ENVI-met 4 LITE. I try to make an image of concentration PM 2.5 in a big city. For this I set PM 2.5 background level 20 µg/m3. But in the result of my simulation I see - see Attachment - a lot of places where the concentration PM 2.5 is under 20 µg/m3. Why?
Thank you in advance.
Attachments
N_z_barierami.jpg

Tim
Posts: 1878
Joined: Mon May 15, 2017 3:46 pm

Re: Background level.

Post by Tim »

Hi,

Did you use PM2.5 of the fixed pollutant profiles or did you define it as user emission profile?
Could you attach the SIMX / INX / EDB as zip here?

Best regards,
Tim

Broni
Posts: 4
Joined: Sat Aug 10, 2019 10:20 am

Re: Background level.

Post by Broni »

Hello,
I used the triple line of the pollution source on the main street - see Attachment, and defined background level = 20µg / m3.
Attachments
INX.7z
(3.83 KiB) Downloaded 1 time
Capture_of_sources.JPG

Tim
Posts: 1878
Joined: Mon May 15, 2017 3:46 pm

Re: Background level.

Post by Tim »

Hi,

Okay, I don't have the sources of your database. However, my assumption about the issue is correct: You defined the user pollutant as PM2.5 but added background concentration for the MultiPollutant PM2.5. You could now either take the emission profile and add it to the PM2.5 emission profile in the database manager and activate MultiPollutant mode in the ENVIguide, or (which is probably much easier) add the background concentration value in the ENVIguide to the User Emission instead of the PM2.5 emission.

Best regards,
Tim

Broni
Posts: 4
Joined: Sat Aug 10, 2019 10:20 am

Re: Background level.

Post by Broni »

Hello,
Thank you for your answer.

I tried following your second tip - add the background concentration value in the ENVIguide to the User Emission instead of the PM2.5 emission - see Capture2 - but I'm not sure if I understood your words correctly because in my new simulation - Oxy035_SL_N - are still points where the concentration level of PM 2.5 is less than 20 µg/m3.
For example Grid(0,49) cut k=3 the Concentration PM 2.5 = 0 µg/m3.

Could you help me solve this problem?
Thank you in advance.
Attachments
Oxy_35_SL_N.jpg
Capture_03.JPG
Capture_02.JPG
Capture_01.JPG

Tim
Posts: 1878
Joined: Mon May 15, 2017 3:46 pm

Re: Background level.

Post by Tim »

Hi,

In the lowest picture, you are seeing the Background Concentration settings. You added 20 ug/m3 to PM2.5. However, PM2.5 is not simulated in your case. You need to add it to the lowest option (User specified pollutant). What you changed there in your test was the density of each PM particle.

Best regards,
Tim

Broni
Posts: 4
Joined: Sat Aug 10, 2019 10:20 am

Re: Background level.

Post by Broni »

Thanks awfully!
Your help is invaluable.
Cordial greetings,
Broni

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