First of, you are comparing a noise density of a spectrum analyzer to a power density measurement range of a power density meter. Two different things, having nothing at all to do with each other. Its a little bit like comparing a digital voltmeter noise (last digits uncertainty, digits toggling with no signal connected) to the measurement range of a power meter.



Not sure what you want to do, you do not tell us. Normally, if you are interested in the impact of electromagnetic radiation on the human body, the mW/m2 is the one you are interested. If you want to measure the EMI as per e.g. FCC, you cannot just do this in a room. You need a special setup. (And anyway, you are in the wrong section, should go to RF forum for more attention.)



The Aaronia should give you a fieled strength (dBuV/m), with an antenna. It is a combination of the antenna used and the measuring device. The antenna has different sensitivities at different frequencies. So it is not just a simple multiplication. You can then calculate a power denstity through the free space impedance, 377 ohms. Pd = E^2/377. But that is (spectrum!) at a given frequncy. You probably want to know the overall power, the integral over the frequency spectrum. You cannot do that with your means (unless the Aaronia can do that for you, have not checked that).



But keep in mind: based on the question you ask, it may not be the best idea to spend money on this (assuming you want to know electrosmog), given you do not have the necessary theoretical background. If you are interested in electrosmog, consultants can do that for you and also explain the test results. Also, an intentional emitter (like a cell phone or wifi device) generate higher EMI levels than e.g. a computer just radiating due to internal clock sources. Alternatively, if you do not want a consultant, a power density meter is as simple as it gets for you. But again, what then do you measure and what do you derive from the results?



