Unlike Photochemical Smog,the Atmospheric Brown Cloud Over Much of South

Unlike photochemical smog,the atmospheric brown cloud over much of south and central Asia

A) occurs only during the daytime,when the sun is shining brightest.
B) occurs year-round and includes black carbon and soot.
C) occurs only in coastal regions,where salt aerosols are most abundant.
D) results from the gases released from abundant rice fields and farm animals.