Table 1.
Results of the parametric test for NO2 concentrations
| Variables (stations) | n | Mean (μg/m3) | Std. Err. | t |
H0 : Xd = 0 Pr(| T| > | t| ) |
Reduction between stations* |
|---|---|---|---|---|---|---|
| Belisario 2018 | 160 | 32.86 | 0.99 | 24.36 | 0.000 | 4.27 |
| Belisario 2019 | 160 | 32.90 | 12.73 | 23.11 | 0.000 | 4.27 |
| Belisario 2020 | 160 | 7.70 | 0.38 | |||
| Carapungo 2018 | 159 | 17.26 | 0.83 | 14.09 | 0.000 | 3.28 |
| Carapungo 2019 | 159 | 21.47 | 0.93 | 20.75 | 0.000 | 4.08 |
| Carapungo 2020 | 159 | 5.26 | 0.30 | |||
| Centro 2018 | 112 | 38.20 | 1.23 | 26.29 | 0.000 | 7.46 |
| Centro 2019 | 112 | 35.83 | 1.35 | 22.33 | 0.000 | 7.00 |
| Centro 2020 | 112 | 5.12 | 0.36 | |||
| Cotocollao 2018 | 158 | 21.27 | 0.87 | 21.67 | 0.000 | 7.46 |
| Cotocollao 2019 | 158 | 11.66 | 0.64 | 13.92 | 4.09 | |
| Cotocollao 2020 | 158 | 2.85 | 0.17 | |||
| El Camal 2018 | 160 | 37.64 | 1.01 | 25.45 | 0.000 | 5.08 |
| El Camal 2019 | 160 | 37.72 | 1.05 | 26.53 | 0.000 | 5.09 |
| El Camal 2020 | 160 | 7.41 | 0.51 | |||
| Guamani 2018 | 72 | 25.77 | 1.55 | 11.44 | 0.000 | 3.43 |
| Guamani 2019 | 72 | 21.21 | 1.43 | 9.31 | 0.000 | 2.82 |
| Guamani 2020 | 72 | 7.51 | 0.59 | |||
| Los Chillos 2018 | 160 | 27.99 | 1.08 | 21.55 | 0.000 | 8.16 |
| Los Chillos 2019 | 160 | 20.53 | 1.02 | 15.30 | 0.000 | 5.99 |
| Los Chillos 2020 | 160 | 3.43 | 0.43 | |||
| Average reduction* | 2018: 5.59 | 2019: 4.76 |
*In comparison with 2020 (number of times)