. Author manuscript; available in PMC: 2020 Jul 23.

Published in final edited form as: Aerosol Air Qual Res. 2018;18(3):565–578. doi: 10.4209/aaqr.2017.10.0418

Table 4.

Shinyei PM sensor calibrations generated from first half of Hyderabad data and their accuracy when applied during a second later period where (Estimate PM) = m × (raw sensor signal) + b for all sensors except the PPD60PV where a nonlinear calibration was used.

	Signal output	Calibration coefficients (PM = m × sensor + b)		calibration period			application period

		m	b	Dates	average	standard deviation	dates	average error	standard deviation error
PPD42NS^a	Digital	40.0	13.3	(1/31–2/4)	0	28.9	(2/7–2/10)	–149	145.3
PPD20V1	Analog	0.45	–75.5	(1/31–2/4, 2/7–2/10)	0	20.3	(2/25–3/4)	9.2	19.9
PPD20V2	Analog	0.46	–84.8	(1/31–2/4, 2/7–2/10)	0	21.6	(2/25–3/4)	–15.9	16.3
PPD20V3	Analog	0.39	–50.4	(1/31–2/4, 2/7–2/10)	0	18.7	(2/25–3/4)	–0.8	17

		PM = $e^{\frac{s e n s o r - d}{c}}$		Calibration period			Application period

		c	d	dates	average	standard deviation	dates	average error	standard deviation error
PPD60PV	Analog	123	2.8	(1/31–2/4, 2/7–2/10)	0	24.1	(2/25–3/4)	–21.9	38.5