Don't choke when estimating plant emissions

摘要

THEY CAN BE OPAQUE,TRANSLUCENT OR invisible.They parade through the sky in Technicolor green,yellow,orange,brown and red,or basic shades of black and white.Varying in fragrance from odorless to offensive,they hug the ground,disperse rapidly into the atmosphere,or just smother the sky as an oppressive blanket of smog.