Pathology

Meteorology

Archaeology

Disease

Coronavirus disease 2019 (COVID-19)

Infectious disease (medical specialty)

Environmental protection

Haze

Biology

Outbreak

China

Virology

Geography

Ecology

Particulates

2019-20 coronavirus outbreak

Air pollution

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Environmental science

Pollution

Medicine

Environmental health

Science

Air pollution epidemic The lockdown enforced in most cities in China in response to the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted in the virtual absence of motor vehicle traffic and sharply reduced manufacturing activity for several weeks. Le et al. report some of the anticipated and unanticipated effects that this had on air pollution there, including unexpectedly high levels of particulate matter abundances and severe haze formation in some areas. This natural experiment will help in the assessment of air pollution mitigation strategies. Science , this issue p. 702

Unexpected air pollution with marked emission reductions during the COVID-19 outbreak in China