Answer to Question #4092 in Microbiology for marvin
In the USA, what is the official standard, for general purposes, for indoor air quality (IAQ)
regarding the acceptable density of bacterial and fungal organisms in the air
a Zero cfu/m3
b <500 cfu/m3
c >750 but <999 cfu/m3
d There are no official standards for microorganisms and IAQ
The answer is "d".
EPA (United States Environmental Protection Agency) does not regulate indoor air, but they do offer assistance in protecting your indoor air quality.