Street protests and air pollution in Hong Kong

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

View graph of relations


  • Peter Brimblecombe


Original languageEnglish
Article number295
Journal / PublicationEnvironmental Monitoring and Assessment
Issue number5
Online published19 Apr 2020
Publication statusPublished - May 2020



June 2019 saw large-scale street protests in Hong Kong that impeded traffic flow along streets in areas around to the Legislative Council building. These had the potential to reduce overall air pollutant emissions from traffic and lower their concentrations. Two roadside monitoring stations relatively close to the Legislative Council reveal that measured concentrations of nitrogen dioxide declined during the protests compared with measurements from other sites by at least 50% on many occasions. There were only subtle changes in particulate loads and no evidence of any reduction in carbon monoxide concentrations. Pedestrianisation and bus route rationalisation are often seen as methods to reduce exposure in congested areas, but the observations here suggest that the substantial improvements in the nitrogen dioxide levels might not be matched by improvements in other pollutants. Plans for changes to street layouts to improve air quality need careful investigation before they are implemented.

Research Area(s)

  • NO2, Roadside air pollution, Street blockage, Traffic associated air pollutants (TRAP), Traffic diversion

Citation Format(s)