Question 49fbe443

a recent study’s estimate is that these crusts reduce global dust emissions by 60 percent each year. 

an estimated 60 percent reduction in global dust emissions each year is due to these crusts, according to a recent study.

these crusts reduce global dust emissions by an estimated 60 percent each year, according to a recent study.

a recent study has estimated that these crusts reduce global dust emissions by 60 percent each year.