Convert ppm and mg/m3

To convert from ppm to mg/m3, the equation is as follows:

• Concentration (mg/m3 ) = 0.0409 x concentration (ppm) x molecular weight 

To convert from mg/m3 to ppm, the equation is as follows:

• Concentration (ppm) = 24.45 x concentration (mg/m3 ) ÷ molecular weight

From - https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.files/fileid/14285#:~:text=If%20the%20concentration%20of%20benzene,per%20cubic%20meter%20(m3).

For formaldehyde:

Molecular weight - 30.031 g/mol