help using the particle tracking and droplets module

[golnaz5100]

Thanks Yvan, for the response.

the concentration is dimentionless in articles, but my problem is that I need to follow the concentration contour in paraview, So I need to see the concentration just like the other variable like particle volume fraction, particle statistical weight,... in paraview.
I found the particle mass concentration in uslaen.f90, do you think by adding this to subroutin I am able to have the particle mass concentrtion?

if yes, where should I add uslaen.f90. whether I have to add it to the extra operation. f90 or in the particle tracking.f90 ( the files that I copy them to SRC)? sorry if I am making mistake but I just used the GUI till now and I do not know anything about the code.
Best regards,
Golnaz