A number of related measures can be used to measure changes in visibility associated with reduced fine particle concentrations.
Many things can be used to measure the changes in how visible fine particles are.
Nothingcan measure the changes in particle visibility.
The man is cooking around a campfire.
A yellow cat jumps to greet a woman.
the people are on the sidewalk
The boy sits on the beach.
I know she'll be able to get another job if she loses this one, so I'm not worried.
The man is sleeping.