Diluent, Pressure, Temperature specifications

[maddalenabugatti]

Hello, I'm using Hapi to compute transmission spectra of molecules in the atmospheres of possible planets.
I have some doubts about the input parameters to compute the 'absorptionCoefficient_Lorentz' and 'transmittanceSpectrum'.

Let's say I want to recreate the atmosphere of the Earth and see how the O2 transmission spectra is.
I use the following code:

`path=8000e2 #cm
temperature=288 #K
pressure=1 #atm

environment = {'l': path,'T':temperature}
nu,coef = absorptionCoefficient_Lorentz(SourceTables='O2', Environment={'p':pressure,'T':temperature}, Diluent={'air':1.0}, HITRAN_units=False)
wavenumbers, transmittance = transmittanceSpectrum(nu,coef,Environment={'T':temperature,'l':path})
`
I have some doubts... Is the pressure and temperature referred just to the O2 quantity, or to the diluent, i.e. air?
And does the diluent include the percentages of the Earth composition (78% Nitrogen, 21% Oxigen etc.)?
Last question: what is exactly 'l' (path length)? Can I consider it like the atmosphere height (8 km)? Because by putting these values I obtain a weird spectrum, which has too much absorption in the transmittance spectrum.
Thank you :)