英文關鍵字
air
asia
atmosphere
background
boy
catastrophe
caucasian
chemical
chimneys
china
choke
city
cough
damage
danger
dangerous
dirty
ecology
environment
factory
gadget
gas
gasp
guy
headache
health
human
illness
industrial
industry
kid
male
man
mask
mobile
people
person
phone
pipes
pollutant
pollution
protect
protection
protective
respirator
sick
smartphone
smoke
smokestack
stack
toxic
urban
virus
wear