CantoDict's (as well as other dictionaries) entries for:
SNORT
哼 hang1 hng6 heng1 hng5 snort; hum; humph
or
SNIFF
嗅 cau3 hung3 xiu4 smell; scent; sniff
歙 kap1 sip3 xi1 she4 sniff; discreet
don't seem to be correct for the usage as in the Subject heading:
SNORTing or SNIFFing tobacco or other substances
SNORT
哼 hang1 hng6 heng1 hng5 snort; hum; humph
or
SNIFF
嗅 cau3 hung3 xiu4 smell; scent; sniff
歙 kap1 sip3 xi1 she4 sniff; discreet
don't seem to be correct for the usage as in the Subject heading:
SNORTing or SNIFFing tobacco or other substances