Question: when was noise pollution added to pollution list
[{'answer': '1972', 'provenance': [{'wikipedia_id': '66599', 'title': 'Noise pollution', 'start_paragraph_id': 32, 'start_character': 25, 'end_paragraph_id': 32, 'end_character': 29, 'bleu_score': 1.0, 'section': 'Section::::Legal status.:United States.\n'}]}]