If a meteorite were large enough, theorists argue, it could propel dust and noxious vapors high into the atmosphere, clouding out the sun and thereby lowering global surface temperature, and leaving chemical compounds like sulfur dioxide in the stratosphere for years where they would mix with clouds to create toxic aerosols and produce acid rain.
빨간색으로 표시한 they는
chemical compounds를 나타내는 건가요?
아님 dust and noxious vapors 를 의미하는 건가요?