The tinted glass of car windows does not influence CO2 measurements of the Aranet4 device as they are performed in a small gas chamber inside of the device with a narrow beamwidth and narrow wavelength laser that can not be influenced with ordinary normal intensity ambient or artificial light. CO2 concentration level in the car is determined by car ventilation system efficiency and how close the device is located to the person in the car - if it is used closer than 1 meter, then measurements can be strongly influenced by the CO2 saturated air that is exhaled by the person.
