But brown clouds, whose environmental and economic impacts are beginning to be unraveled by scientists, are complicating and in some cases aggravating their effects.

• 不过在众多科学家陆续阐明褐云所带来的环璄与经济冲击之际，彰显出人类对其严重的冲击效应还有很大的检讨和防治空间。