英文關鍵字
particle
air
virus
bacteria
dust
closeup
tiny
infection
small
epidemic
background
macro
droplet
hazard
moving
hazardous
suspended
light
protective
bright
protection
sun
scatter
close
infected
sunlight
fly
infect
aerial
cough
transmission
aerosol
toxic
carry
dusty
airborne
sneeze
mask
shine
spread
carrier
material
shiny
danger
cell
black
microscope
floating
microbe