Table 2.

Results of the parametric test for PM2.5 concentrations

Variables (stations)	n	Mean (μg/m3)	Std. Dev.	t	H0 : Xd = 0 Pr(| T|  > | t| )	Reduction between stations*
Belisario 2018	167	19.24	0.66	5.71	0.000	1.45
Belisario 2019	167	22.89	0.91	9.43	0.000	1.73
Belisario 2020	167	13.23	0.77
Carapungo 2018	164	18.29	0.91	5.70	0.000	1.53
Carapungo 2019	164	21.67	1.04	10.14	0.000	1.81
Carapungo 2020	164	11.95	0.78
Centro 2018	121	22.95	0.80	7.94	0.000	1.83
Centro 2019	121	23.23	0.94	10.83	0.000	1.85
Centro 2020	121	12.53	0.85
Cotocollao 2018	166	15.08	0.68	3.97	0.000	1.30
Cotocollao 2019	166	22.41	1.09	9.87	0.000	1.93
Cotocollao 2020	166	11.63	0.69
El Camal 2018	168	23.98	1.21	5.20	0.000	1.50
El Camal 2019	168	25.48	1.12	7.44	0.000	1.59
El Camal 2020	168	15.99	0.96
Guamani 2018	162	22.59	0.96	4.44	0.000	1.36
Guamani 2019	162	19.43	0.78	2.69	0.008	1.17
Guamani 2020	162	16.58	0.85
Los Chillos 2018	165	17.17	0.70	3.32	0.001	1.31
Los Chillos 2019	165	18.25	0.74	4.83	0.000	1.40
Los Chillos 2020	165	13.08	0.94
Average reduction*					2018: 1.47	2019: 1.64

*In comparison to 2020 (number of times)