Table 1.

Summary of results from main and additional analyses.

	4-week post-intervention (main analyses)		2-week post-intervention period, period 1		2-week post-intervention period, period 2		3-day lagged intervention start
Site	Effecta (μg/m3)	95% CI	Effect (μg/m3)	95% CI	Effect (μg/m3)	95% CI	Effect (μg/m3)	95% CI
cITS approach
LAN (T)	−9.34	−23.58; 4.90	−13.73	−31.24; 3.78	−4.72	−22.95; 13.51	−12.08	−26.73; 2.57
STA (T)	−10.02	−19.25; -0.79	−10.78	−22.04; 0.48	−9.17	−21.07; 2.72	−12.61	−22.00; -3.21
LOT (UB)	−1.94	−11.90; 8.03	−3.82	−16.01; 8.37	0.27	−12.59; 13.13	−4.08	−14.32; 6.17
ALL (B)	−1.37	−12.77; 10.02	−2.57	−16.09; 10.95	0.17	−14.44; 14.78	−0.06	−11.84; 11.73
JOH (B)	0.75	−8.79; 10.29	−0.73	−12.21; 10.74	2.52	−9.74; 14.78	0.15	−9.69; 9.99
SC approach
LAN (T)	−15.65	−27.58; -4.09	−21.46	−42.82; -8.19	-b	–	−18.49	−30.73; - 6.55
STA (T)	−15.1	−24.82; -9.83	−16.52	−29.30; -9.01	–	–	−17.82	−26.91; -11.92
LOT (UB)	−8.84	−20.04; -2.51	−10.04	−24.09; -4.32	–	–	−10.82	−21.06; -4.37
ALL (B)	−3.08	−12.59; 5.39	−3.35	−15.53; 5.71	–	–	−5.47	−14.40; 2.93
JOH (B)	−4.69	−11.65; 1.86	−7.46	−15.92; −1.71		–	−6.02	−12.98; 0.67

Bold: denotes statistical significance at an alpha level of 5%.

AbbreviationscITS: controlled ITS; SC: synthetic control; (T): traffic site; (UB): urban background site; (B): background site.

^aEffects are expressed as the effect over the post-intervention time period, e.g. −9.34 corresponds to a reduction in NO₂ concentration of 9.34 μg/m³ between the pre- and post-intervention periods in 2020 relative to the control year(s).

^bThe SC approach did not allow for testing the second 2-week post-intervention period, thus no results are reported.