sentence: Dust can hang in the air for years.
sentences_before: This big dirt is still very small. It's about the width of a human hair. The big dirt does not stay in the air for years though because rain hits it and brings it to the surface. It actually only stays in the air for about 7 days. But this is still a long time, and can cause changes in the temperature of the Earth.
concept_name: dust
headings: Global warming Temperature changes Dust and dirt
categories: Energy Climate change Air pollution