Statistical Evaluation of PM2.5 Induced Air Pollution of Dhaka City during Covid-19 Outbreak for Selected Period

1. Statistical Evaluation of PM2.5 Induced Air Pollution of Dhaka City during
Covid-19 Outbreak for Selected Period

2. Background
• Bangladesh Being most polluted
country for PM2.5
• Dhaka, vulnerable city to both
PM2.5 pollution and COVID-19
transmission in Bangladesh
• Lockdown : Lower covid rate as
well as amount of air pollutant

3. Objective
• Statistically analyse PM2.5 concentrations during individual lockdown
periods and selectively comparing to previous years’ dataset
• Understand the change in PM2.5 concentration following covid-19
induced mortality
• Identify pollution trend during outbreak period
• Statistically establish that PM2.5 induced air pollution significantly
decreased during the lockdown as well as the major outbreak period

4. Data Overview
Data Source
U.S. Embassy in Bangladesh
- US embassy air quality data (2019-2021)
- Address: Madani Avenue Baridhara, Dhaka 1212

5. Data Overview
Data Type
Hourly average PM2.5 data Concentration (μg/m3) and AQI value

6. Methodology
Framework
Hourly average
PM2.5 data
24h-Daily average
PM2.5 data
Analysis

7. Methodology
Analysis
Descriptive Analysis
- Box Plot
- SD
Linear Regression Hypothesis Testing

8. Analysis and Discussion

9. Lockdown
Periods
• Lockdown 01: March 24 – May 30, 2020
• “General Holiday”
• Lockdown 02: April 14 – April 28, 2021
• “Strict Lockdown”
• Lockdown 03: July 01 – July 14, 2021
• Lockdown 04: July 23 – August 11, 2021
• “Strict Lockdown”

10. Comparison with
Previous Year(s)
• Lockdown 01
• ~19% decrease in 2020
• Lesser deviation
• Less amount of extreme data
Lockdown
Period
2019 2020
Date Median | SD
March 23 –
May 30
63.9 |
39.2
51.9 |
27.2
Difference
-12 | -
18.8%

11. Comparison with
Previous Year(s)
• Lockdown 02
 Both 2020-2021 in LD
 Both decreased compared to 2019
 2020: higher decrease
Lockdown
Period
2019 2020 2021
Date Median | SD
April 14 - April
28
69.5 |
23.9
37.1 |
11.5
54.5 | 38.1
Difference
-32.4 |-
46.6%
+17.4 |
+46.9%

12. Comparison of 2021 LD
w/ Previous Year
• Lockdown 03
 Only 2021 in LD
 2020: Higher variability
 2021: increase
 Eid-Ul-Adha period
Lockdown
Period
2019 2020 2021
Date Median | SD
July 01 –
July 14
28.6 |
6.1
24.3 |
13.8
36.6 | 6.9
Difference
-4.3 | -
15.0%
+12.3 |
+50.6%

13. Comparison of 2021 LD
w/ Previous Year
• Lockdown 04
 Only 2021 in LD
 2020: increased to 2019
 2021 decreased but higher variability
 Factories opened halfway
Lockdown
Period
2019 2020 2021
Date Median | SD
July 23 –
August 23
27.6 |
12.8
31.0 |
10.2
24.6 |
13.5
Difference
+3.4 |
+12.3%
-6.4 | -
20.6%

14. PM2.5 Conc. Trend • Lockdown 01
• Decreasing
trend w/
time
• Data used:
March 24 –
May 19
 Unavaila
bility of
PM2.5
data
• Till April 6:
Garment &
other
industry
workers back
& forth
towards
Dhaka: high
PM2.5
R² = 0.2675
0
20
40
60
80
100
120
140
160
20-Mar 30-Mar 9-Apr 19-Apr 29-Apr 9-May 19-May 29-May
PM2.5
conc.
[μ/m3]
Time
2020 – Lockdown 01

15. PM2.5 Conc. Trend
• Lockdown 02
• Increasing trend
 Not very good fit
• Shops, malls opened from 24-
25
 Spike in PM2.5
R² = 0.1486
0
20
40
60
80
100
120
140
160
180
200
13-Apr 15-Apr 17-Apr 19-Apr 21-Apr 23-Apr 25-Apr 27-Apr 29-Apr
PM2.5
conc.
[μ/m3]
Time
2021 – Lockdown 02

16. PM2.5 Conc. Trend
• Lockdown 03
• Decreasing trend
• Higher values in latter part
 Possible sacrificial cattle
transfer
For Eid-Ul-Azha
R² = 0.2416
0
5
10
15
20
25
30
35
40
45
50
28-Jun 1-Jul 4-Jul 7-Jul 10-Jul 13-Jul 16-Jul
PM2.5
conc.
[μ/m3]
Time
2021 – Lockdown 03

17. PM2.5 Conc. Trend
• Lockdown 04
• Stronger Increasing trend
• Later spike
 Factories opened after
1st August
R² = 0.7357
0
10
20
30
40
50
60
20-Jul 24-Jul 28-Jul 1-Aug 5-Aug 9-Aug 13-Aug
PM2.5
conc.
[μ/m3]
Time
2021 – Lockdown 04

18. Mortality rate and Air
Quality
• Lockdown 01
• Somewhat decreasing
PM2.5 trend w/
increasing mortality
R² = 0.1424
0
20
40
60
80
100
120
140
160
0 5 10 15 20 25
PM2.5
conc.
[μ/m3]
Covid-19 Deaths
PM2.5 vs Deaths [2020 – Lockdown 01]

19. Mortality rate and Air
Quality
• Lockdown 02
• Somewhat decreasing but
some random values
R² = 0.1385
0
20
40
60
80
100
120
140
160
180
200
60 70 80 90 100 110 120
PM2.5
conc.
[μ/m3]
Covid-19 Deaths
PM2.5 vs Deaths [2021 – Lockdown 02]

20. Mortality rate and Air
Quality
• Lockdown 03
• More or less random
relationship
R² = 0.0757
0
5
10
15
20
25
30
35
40
45
50
100 120 140 160 180 200 220 240
PM2.5
conc.
[μ/m3]
Covid-19 Deaths
PM2.5 vs Deaths [2021 – Lockdown 03]

21. Mortality rate and Air
Quality
• Lockdown 04
• Increasing trend
• Most of the increased values
come with factories opening
R² = 0.2847
0
10
20
30
40
50
60
150 170 190 210 230 250 270
PM2.5
conc.
[μ/m3]
Covid-19 Deaths
PM2.5 vs Deaths [2021 – Lockdown 04]

22. More to be
Done
• Hypothesis Testing 1
• Is there any significant change in PM2.5 due to Covid outbreak?
• Hypothesis Testing 2
• Is there any significant change in PM2.5 during different
lockdown periods?
• Regression 1
• Is there any relationship between Covid-19 mortality rate and
PM2.5 throughout the outbreak period?

23. Ask
gglclstsm@gmail.com