Table 2.
Summary statistics of PM2.5 concentration monitored by BAM-1022 across the hours of the day, Addis Ababa, Ethiopia, 2017–2020.
| Time | Time descriptiona | Minimum | Median | Mean | Maximum | SD | |
|---|---|---|---|---|---|---|---|
| TASH | Before 5h00 | Midnight | 1 | 35 | 37.8 | 366 | 23.4 |
| 6h00 to 9h00 | Early morning | 3 | 54 | 63.4 | 295 | 37.6 | |
| 10h00 to 15h00 | Day time | 0 | 26 | 30.9 | 260 | 18.5 | |
| 16h00 to 19h00 | Late afternoon | 0 | 26 | 38.2 | 234 | 33.5 | |
| After 20h00 | Night | 1 | 34 | 49.6 | 452 | 31.4 | |
| US Embassy | Before 5h00 | Midnight | 0 | 15 | 17.5 | 246 | 11.1 |
| 6h00 to 9h00 | Early morning | 0 | 23 | 27.3 | 354 | 18.2 | |
| 10h00 to 15h00 | Day time | 0 | 20 | 24.6 | 248 | 15.9 | |
| 16h00 to 19h00 | Late afternoon | 0 | 19 | 24.3 | 375 | 18.5 | |
| After 20h00 | Night | 1 | 24 | 29.7 | 402 | 16.5 | |
| School | Before 5h00 | Midnight | 0 | 32 | 35.9 | 332 | 22.5 |
| 6h00 to 9h00 | Early morning | 4 | 48 | 52.6 | 309 | 27.6 | |
| 10h00 to 15h00 | Day time | 0 | 18 | 21.5 | 98 | 12.3 | |
| 16h00 to 19h00 | Late afternoon | 1 | 21 | 26.0 | 203 | 19.0 | |
| After 20h00 | Night | 5 | 30 | 44.1 | 347 | 24.0 |
aThis is to customize the daily profile PM2.5 concentration in reference to Figure 3 in order to show the likely of exposure given human mobility according the context of local time. The increased PM concentration was indicative during early morning (6:00-9:00 am) and relatively low peaks during late afternoon, around 20:00 pm.