Quantifying the Impact of the COVID-19 Pandemic Restrictions on CO, CO2, and CH4 in Downtown Toronto Using Open-Path Fourier Transform Spectroscopy
Abstract
:1. Introduction
2. Materials and Methods
2.1. Measurements Location
2.2. OP-FTIR Instrumentation
2.3. Data Processing and Gas Retrievals
2.4. Calculating Enhancement above Background, Daily Results, and Diurnal Variation
3. Results and Discussion
3.1. Daily Mole Fractions and Enhancements above Background
3.2. Changes in Diurnal Variations
3.3. Changes in Local Traffic and Gas Enhancement from Background
4. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Gases Fitted | Interfering Gases | Spectral Window (cm) |
---|---|---|
CO, CO, NO | HO | 2141–2235 |
CH | HO | 2900–3027 |
HO, HDO | CH | 2713–2952 |
Year | Period 1 | Traffic Counts/hr | Period 2 | Traffic Counts/hr |
---|---|---|---|---|
2018 | 13 January to 13 March | 7343 | 14 March to 18 May | 7345 |
2019 | 13 January to 13 March | 6892 | 14 March to 18 May | 7801 |
2020 | 13 January to 13 March | 7450 | 14 March to 18 May | 4747 |
2021 | Period 3 | |||
14 January to 7 March | 6175 * |
Periods | CO (ppb) | CO (ppb) | CO (ppm) | CO (ppm) | CH (ppb) | CH (ppb) |
---|---|---|---|---|---|---|
2018 | ||||||
Period 1 | 176 | 35.1 | 427 | 12.3 | 2160 | 141.9 |
Period 2 | 167 | 33.5 | 425 | 10.4 | 2063 | 82.4 |
Difference, P2-P1 | Not sig | Not sig | Not sig | Not sig | −96.8 (−149.4, −44.3) | −59.5 (−102.2, −16.8) |
Relative difference (%) | NA | NA | NA | NA | −4.5 ± 2.4% | −42 ± 30% |
2019 | ||||||
Period 1 | 196 | 53.3 | 430 | 10.8 | 2035 | 48.0 |
Period 2 | 174 | 48.0 | 424 | 11.2 | 2056 | 75.7 |
Difference, P2-P1 | −22.2 (−39.9, −4.6) | Not sig | −5.5 (−10.1, −0.9) | Not sig | Not sig | 27.7 (3.0, 52.3) |
Relative difference (%) | −11 ± 9% | NA | −1.3 ± 1.1% | NA | NA | 58 ± 51% |
2020 | ||||||
Period 1 | 179 | 44.6 | 436 | 10.7 | 2088 | 79.7 |
Period 2 | 145 | 21.7 | 424 | 6.8 | 2055 | 60.6 |
Difference, P2-P1 | −34.2 (−45.8, −22.7) | −22.9 (−33.0, −12.7) | −12.1 (−15.2, −9.0) | −3.9 (−6.6, −1.3) | −33.3 (−58.0, −8.7) | Not sig |
Relative difference (%) | −19 ± 6% | −51 ± 23% | −2.8 ± 0.7% | −36 ± 24% | −1.6 ± 1.2% | NA |
2021 | ||||||
Period 3 | 157 | 25.8 | 429 | 7.2 | 2051 | 47.3 |
Difference, 21P3-20P1 | −22.3 (−34.2, −10.5) | −18.8 (−29.5, −8.2) | −6.5 (−9.6, −3.3) | −3.5 (−6.4, −0.7) | −36.5 (−61.6, −11.3) | −32.4 (−55.5, −9.3) |
Relative difference (%) | −12 ± 7% | −42 ± 24% | −2.5 ± 0.7% | −33 ± 26% | −1.7 ± 1.2% | −41 ± 29% |
Period | Time | DVP at Gerrard | Gardiner at Bay | Gardiner at Windermere |
---|---|---|---|---|
2020 Period 1 | 7:00–8:00, weekdays | 8474 | 6713 | 8059 |
12:00–16:00, all days | 7256 | 6217 | 8876 | |
2020 Period 2 | 7:00–8:00, weekdays | 4740 | 3670 | 5817 |
12:00–16:00, all days | 4736 | 4305 | 5199 | |
2020P2-2020P1 (%) | 7:00–8:00, weekdays | −44 (%) | −45 (%) | −28 (%) |
12:00–16:00, all days | −35 (%) | −31 (%) | −41 (%) | |
2021 Jan14–Feb18 * | 7:00–8:00, weekdays | 6118 | 4551 | 7143 |
12:00–16:00, all days | 6307 | 5054 | 7164 | |
2021(Jan–Feb)-2020P1 (%) | 7:00–8:00, weekdays | −28 (%) | −32 (%) | −11 (%) |
12:00–16:00, all days | −13 (%) | −19 (%) | −19 (%) |
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You, Y.; Byrne, B.; Colebatch, O.; Mittermeier, R.L.; Vogel, F.; Strong, K. Quantifying the Impact of the COVID-19 Pandemic Restrictions on CO, CO2, and CH4 in Downtown Toronto Using Open-Path Fourier Transform Spectroscopy. Atmosphere 2021, 12, 848. https://doi.org/10.3390/atmos12070848
You Y, Byrne B, Colebatch O, Mittermeier RL, Vogel F, Strong K. Quantifying the Impact of the COVID-19 Pandemic Restrictions on CO, CO2, and CH4 in Downtown Toronto Using Open-Path Fourier Transform Spectroscopy. Atmosphere. 2021; 12(7):848. https://doi.org/10.3390/atmos12070848
Chicago/Turabian StyleYou, Yuan, Brendan Byrne, Orfeo Colebatch, Richard L. Mittermeier, Felix Vogel, and Kimberly Strong. 2021. "Quantifying the Impact of the COVID-19 Pandemic Restrictions on CO, CO2, and CH4 in Downtown Toronto Using Open-Path Fourier Transform Spectroscopy" Atmosphere 12, no. 7: 848. https://doi.org/10.3390/atmos12070848