Table 1.

Total emission (ton) of different air pollutants in 2019 and 2020 derived from Sentinel TROPOMI.

City	NO2			CO
	2019	2020	Difference (%)	2019	2020	Difference (%)
Antwerp	1.73	1.31	−24.14	215.83	212.80	−1.40
Barcelona	0.82	0.58	−29.49	104.91	101.91	−2.86
Brussels	1.20	0.86	−27.95	167.84	167.68	−0.10
Chicago	5.55	3.88	−30.09	656.87	652.04	−0.74
Cologne	3.62	2.47	−31.77	426.27	428.37	0.49
Denver	2.97	1.98	−33.43	336.58	343.06	1.92
Detroit	3.16	1.89	−40.29	409.95	393.18	−4.09
Frankfurt	2.14	1.36	−36.36	263.32	261.39	−0.73
London	12.45	8.20	−34.15	1644.88	1627.06	−1.08
Los Angeles	10.63	9.51	−10.54	1405.58	1390.45	−1.08
Madrid	5.18	3.42	−34.03	555.52	547.84	−1.38
Milan	2.15	1.36	−36.85	196.23	190.00	−3.17
New York	8.73	6.21	−28.86	899.48	861.33	−4.24
Paris	1.00	0.54	−45.94	112.10	109.37	−2.43
Philadelphia	3.17	2.08	−34.45	411.40	397.21	−3.45
Rotterdam	2.50	1.83	−26.72	342.27	342.31	0.01
Sao Paulo	8.39	6.95	−17.17	1139.46	1095.22	−3.88
Tehran	25.09	18.93	−24.54	786.14	773.67	−1.59
Turin	1.23	0.78	−36.83	136.12	132.54	−2.63
Utrecht	0.74	0.49	−33.70	104.73	104.32	−0.40