Table A6.
COVID-19 lockdowns and air pollution – Alternative functional forms.
| Panel A: Satellite air pollution | ||||||
| Air quality: |
Optimal bandwidth |
Optimal bandwidth +10 days |
Optimal bandwidth −10 days |
|||
| NO2 |
(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
| Model 1: Cubic interaction model | ||||||
| Lockdown = 1 | −0.487∗∗ (0.241) |
0.377 (0.305) |
−0.631∗∗∗ (0.220) |
−0.571∗∗∗ (0.221) |
−0.338 (0.264) |
−0.294 (0.264) |
| Model 2: Quartic interaction model | ||||||
| Lockdown = 1 | −1.058∗∗∗ (0.184) |
−1.242∗∗∗ (0.233) |
−1.193∗∗∗ (0.173) |
−1.032∗∗∗ (0.173) |
−0.939∗∗∗ (0.200) |
−0.832∗∗∗ (0.200) |
| Model 3: Quintic interaction model | ||||||
| Lockdown = 1 |
−0.710∗∗∗ (0.217) |
−0.191 (0.275) |
−0.851∗∗∗ (0.199) |
−0.754∗∗∗ (0.199) |
−0.534∗∗ (0.239) |
−0.469∗∗ (0.239) |
| Means before lockdowns | 23.281 | 23.281 | 23.281 | 23.281 | 23.281 | 23.281 |
| Controls | No | Yes | No | Yes | No | Yes |
| Country and time FE | Yes | Yes | Yes | Yes | Yes | Yes |
| Observations |
260,007 |
257,339 |
303,316 |
300,266 |
216,917 |
214,775 |
| Panel B: Station-based air pollution | ||||||
| Air quality: |
Optimal bandwidth |
Optimal bandwidth +10 days |
Optimal bandwidth −10 days |
|||
| PM2.5 |
(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
| Model 1: Cubic interaction model | ||||||
| Lockdown = 1 | −1.155∗∗ (0.579) |
−0.427 (0.621) |
−1.883∗∗∗ (0.548) |
−1.001∗ (0.592) |
0.320 (0.620) |
0.869 (0.659) |
| Model 2: Quartic interaction model | ||||||
| Lockdown = 1 | −3.819∗∗∗ (0.436) |
−2.021∗∗∗ (0.479) |
−4.156∗∗∗ (0.411) |
−2.233∗∗∗ (0.452) |
−3.386∗∗∗ (0.463) |
−1.573∗∗∗ (0.506) |
| Model 3: Quintic interaction model | ||||||
| Lockdown = 1 |
−2.236∗∗∗ (0.521) |
−1.056∗ (0.565) |
−2.875∗∗∗ (0.493) |
−1.605∗∗∗ (0.538) |
−0.695 (0.557) |
0.451 (0.600) |
| Means before lockdowns | 64.824 | 64.824 | 64.824 | 64.824 | 64.824 | 64.824 |
| Controls | No | Yes | No | Yes | No | Yes |
| Country and time FE | Yes | Yes | Yes | Yes | Yes | Yes |
| Observations | 90,938 | 79,200 | 100,869 | 89,117 | 80,962 | 69,238 |
Notes: ∗∗∗p < 0.01, ∗∗p < 0.05, ∗p < 0.1. Results of RDD using the optimal bandwidths based on Imbens and Kalyanaraman (2012). The optimal bandwidths are 62 and 88 days for satellite and station-based data, respectively. Clustered standard errors in parentheses are robust to within-day and within-country serial correlation. Control variables are daily temperature and rainfall (humidity for station-based data).