'pollution-free' is a compound word formed from 'pollution' and 'free', where 'pollution' originates from Latin 'pollutio', meaning 'defilement', and 'free' from Old English 'freo', meaning 'not in bondage'.

'pollution' evolved from the Latin 'pollutio' through Old French 'pollucion', while 'free' has remained relatively unchanged from Old English 'freo'.

Initially, 'pollution' referred to 'defilement or desecration', but now it primarily refers to 'environmental contamination'. 'Free' has consistently meant 'not subject to'.