Evaluation of Low-Cost Sensors for Ambient PM_2.5 Monitoring

Table 3

Coefficients of determination () for tested PM sensors at different time scales.

Sensor model	SDS011			ZH03A			PMS7003			PMS7003 “AE”			OPC-N2
Unit	1	2	3	1	2	3	1	2	3	1	2	3	1	2	3
1 min	0.79	0.83	0.80	—	0.70	0.74	0.85	0.85	0.83	0.83	0.83	0.80	0.59	0.43	0.46
15 min	0.80	0.85	0.81	—	0.71	0.77	0.87	0.87	0.85	0.85	0.85	0.81	0.60	0.44	0.47
1 hour	0.82	0.86	0.83	—	0.73	0.81	0.88	0.89	0.86	0.87	0.86	0.83	0.61	0.44	0.48
24 hours	0.88	0.90	0.87	—	0.78	0.89	0.93	0.93	0.91	0.91	0.91	0.88	0.69	0.53	0.59

Unit no. 1 was excluded from calculations due to malfunction; calculated for the period 21 August 2017–24 December 2017, before sensor replacement.