Block that implements the functionality of "Air quality measurement" from VDI 3813 [1, section 6.1.7, p. 15].
"The sensor function Air quality measurement (RAFL section 2, column 6; informative function block Figure 8) provides information allowing conclusions to be drawn about the air quality in a room." [1, section 6.1.7, p. 15]
Because the specification of the air quality signal is indefinite, in this case a value between 0 and 1 had been chosen to represent the air quality, whereas the value 0 stands for the worst quality and 1 for the best quality.