### Volume 11, Number 7

Oct 1987

# Changing PPM into Micrograms/M3

The 1978 edition of Garry Thomson's The Museum
Environment tells you on p. 125 how to convert parts per
million to micrograms per cubic meter. The formula is in a
footnote:

M 1 ppm= ------ ug/m^{3} 0.0224

where M is the molecular weight of the pollutant gas.