Question: the warm dry and dusty air mass that is formed over the sahara desert is known as
[{'answer': 'sandstorm', 'provenance': [{'wikipedia_id': '60605', 'title': 'Dust storm', 'start_paragraph_id': 1, 'start_character': 26, 'end_paragraph_id': 1, 'end_character': 35, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '60605', 'title': 'Dust storm', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 464, 'bleu_score': 0.942340155314736, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9649024897612955517}, 'section': 'Section::::Abstract.'}]}]