Illustrate exposure time in the concentration plot
After receiving the user feedback in #118 (closed) , I think it would be nice to illustrate the start and end time of the activity/exposure in the concentration plot - like we have in the mathematica model:
(exposure time in light grey) - corresponding to a start exposure time @ t=0 and end exposure time @ t=3
FYI, in the plot the presence of the infected person can be determined by the solid black line, no need to do anything further to illustrate the presence of the infected occupant