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Mashayekhi R, Pavlovic R, Racine J, Moran MD, Manseau PM, Duhamel A, Katal A, Miville J, Niemi D, Peng SJ, Sassi M, Griffin D, McLinden CA. Isolating the impact of COVID-19 lockdown measures on urban air quality in Canada. AIR QUALITY, ATMOSPHERE, & HEALTH 2021; 14:1549-1570. [PMID: 34025821 PMCID: PMC8130219 DOI: 10.1007/s11869-021-01039-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 04/28/2021] [Indexed: 05/14/2023]
Abstract
UNLABELLED We have investigated the impact of reduced emissions due to COVID-19 lockdown measures in spring 2020 on air quality in Canada's four largest cities: Toronto, Montreal, Vancouver, and Calgary. Observed daily concentrations of NO2, PM2.5, and O3 during a "pre-lockdown" period (15 February-14 March 2020) and a "lockdown" period (22 March-2 May 2020), when lockdown measures were in full force everywhere in Canada, were compared to the same periods in the previous decade (2010-2019). Higher-than-usual seasonal declines in mean daily NO2 were observed for the pre-lockdown to lockdown periods in 2020. For PM2.5, Montreal was the only city with a higher-than-usual seasonal decline, whereas for O3 all four cities remained within the previous decadal range. In order to isolate the impact of lockdown-related emission changes from other factors such as seasonal changes in meteorology and emissions and meteorological variability, two emission scenarios were performed with the GEM-MACH air quality model. The first was a Business-As-Usual (BAU) scenario with baseline emissions and the second was a more realistic simulation with estimated COVID-19 lockdown emissions. NO2 surface concentrations for the COVID-19 emission scenario decreased by 31 to 34% on average relative to the BAU scenario in the four metropolitan areas. Lower decreases ranging from 6 to 17% were predicted for PM2.5. O3 surface concentrations, on the other hand, showed increases up to a maximum of 21% close to city centers versus slight decreases over the suburbs, but Ox (odd oxygen), like NO2 and PM2.5, decreased as expected over these cities. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11869-021-01039-1.
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Affiliation(s)
- Rabab Mashayekhi
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Radenko Pavlovic
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Jacinthe Racine
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Michael D. Moran
- Air Quality Research Division, Environment and Climate Change Canada, Toronto, Ontario Canada
| | - Patrick M. Manseau
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Annie Duhamel
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Ali Katal
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Jessica Miville
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - David Niemi
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Si Jun Peng
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Mourad Sassi
- Air Quality Policy-Issue Response Section, Canadian Meteorological Center, Environment and Climate Change Canada, Dorval, Quebec, Canada
| | - Debora Griffin
- Air Quality Research Division, Environment and Climate Change Canada, Toronto, Ontario Canada
| | - Chris Anthony McLinden
- Air Quality Research Division, Environment and Climate Change Canada, Toronto, Ontario Canada
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Bottenheim JW, Sirois A. Long-term daily mean mixing ratios of O3, PAN, HNO3, and particle nitrate at a rural location in eastern Canada: Relationships and implied ozone production efficiency. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/95jd03001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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