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1·This would involve using sulphur or hydrogen sulphide aerosols so that sulphur dioxide would form clouds, which would, in turn, lead to global dimming.

这包括使用硫或硫化氢气溶胶，使二氧化硫形成云层，进而导致全球变暗。

2·It is a major reason for global dimming, which has been caused by an increased amount of aerosols in the air since 1970.

这是导致“全球变暗”的主要原因之一。全球变暗的现象始于1970年，是空气中的浮质(悬浮微粒)增加所致。