Subtle Changes or Dramatic Perceptions of Air Pollution in Sydney during COVID-19

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

11 Scopus Citations
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Detail(s)

Original languageEnglish
Article number2
Pages (from-to)1-15
Journal / PublicationEnvironments - MDPI
Volume8
Issue number1
Online published1 Jan 2021
Publication statusPublished - Jan 2021

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Abstract

The COVID-19 pandemic made it critical to limit the spread of the disease by enforcing human isolation, restricting travel and reducing social activities. Dramatic improvements to air quality, especially NO2, have often characterised places under COVID-19 restrictions. Air pollution measurements in Sydney in April 2019 and during the lockdown period in April 2020 show reduced daily averaged NO2 concentrations: 8.52 ± 1.92 and 7.85 ± 2.92 ppb, though not significantly so (p1~0.15) and PM2.5 8.91 ± 4.94 and 7.95 ± 2.64 µg m−3, again a non-significant difference (p1~0.18). Satellite imagery suggests changes that parallel those at ground level, but the column densities averaged over space and time, in false-colour, are more dramatic. Changed human mobility could be traced in increasing times spent at home, assessed from Google Mobility Reports and mirrored in decreased traffic flow on a major road, suggesting compliance with the restrictions. Electricity demand for the State of New South Wales was low under lockdown in early April 2020, but it recovered rapidly. Analysis of the uses of search terms: bushfires, air quality, haze and air pollution using Google Trends showed strong links between bushfires and pollution-related terms. The smoke from bushfires in late 2019 may well have added to the general impression of improved air quality during lockdown, despite only modest changes in the ground level measurements. This gives hints that successful regulation of air quality requires maintaining a delicate balance between our social perceptions and the physical reality.

Research Area(s)

  • Australia, Bushfires, Lockdown, Public perception, Social media, Traffic, Visibility

Citation Format(s)

Subtle Changes or Dramatic Perceptions of Air Pollution in Sydney during COVID-19. / Brimblecombe, Peter; Lai, Yonghang.
In: Environments - MDPI, Vol. 8, No. 1, 2, 01.2021, p. 1-15.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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