PMC:7547912 / 4129-4280 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T27","span":{"begin":0,"end":151},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Based on different national quality standards and dose-response relationships of pollutants, countries have different air quality indices (Zhang et al."}