Effect of calibration environment on the performance of direct-reading organic vapor monitors

Figures & data

Table 1. False-positive, false-negative, and erroneously high measurements as percentage of trials for monitor groups

	Condition	FID (%)	PID (%)	SAP (%)
False positives	Same/cold	70	10	0
	Different/cold	73	0	0
	Same/hot	0	67	100
	Different/hot	67	77	67
False negatives	Same/cold	23	0	1
	Different/cold	0	2	23
	Same/hot	38	25	0
	Different/hot	0	4	22
Erroneously high	Same/cold	0	0	3
	Different/cold	12	0	7
	Same/hot	0	8	26
	Different/hot	100	39	46
Total failure	Same/cold	23	0	4
	Different/cold	12	2	30
	Same/hot	38	33	26
	Different/hot	100	43	68

Table 2. Summary statistics for monitor measurements by part (Part 1—Same and Part 2—Different) and nominal cyclohexane concentration

		Nominal Cyclohexane Concentration
		30 ppm					150 ppm					300 ppm					475 ppm
Monitor	Part	N	% F	Mean (ppm)	%RSD	% CT	N	% F	Mean (ppm)	%RSD	%CT	N	% F	Mean (ppm)	%RSD	% CT	N	% F	Mean (ppm)	%RSD	% CT
FID group	1	60	0	26	54	80	60	0	79	85	55	60	0	136	104	41	60	0	210	109	43
FID group	2	30	50	32	19	96	24	60	120	47	76	30	50	318	17	94	22	63	347	55	68
PID group	1	60	0	13	102	41	50	17	160	20	111	60	0	376	28	116	60	0	510	19	107
PID group	2	37	38	17	98	53	47	22	186	35	120	54	10	370	26	119	55	8	537	30	111
SAP group	1	29	52	31	41	95	59	2	217	18	149	58	3	446	7	138	60	0	644	6	134
SAP group	2	39	35	4	108	12	39	35	124	68	78	40	33	281	59	88	59	2	621	46	130
FID1	1	20	0	25	56	77	20	0	89	67	63	20	0	204	65	61	20	0	122	135	26
FID1	2	10	50	36	4	108	7	65	94	76	56	10	50	344	3	102	6	70	205	69	40
FID2	1	20	0	20	74	60	20	0	84	71	60	20	0	164	99	49	20	0	183	94	37
FID2	2	10	50	24	3	71	10	50	101	38	62	10	50	246	5	73	10	50	278	33	56
FID3	1	20	0	34	30	102	20	0	63	127	42	20	0	40	137	13	20	0	325	89	66
FID3	2	10	50	36	4	109	7	65	174	2	115	10	50	363	4	107	6	70	606	8	116
PID1	1	20	0	14	101	43	20	0	173	25	118	20	0	386	27	120	20	0	558	21	117
PID1	2	17	15	27	78	82	15	25	184	49	118	18	10	433	25	138	18	10	535	45	109
PID2	1	20	0	15	105	46	20	0	158	13	109	20	0	427	26	133	20	0	522	14	109
PID2	2	10	50	14	23	43	15	25	182	25	117	17	15	374	16	120	18	10	568	14	119
PID3	1	20	0	11	100	33	10	50	138	3	100	20	0	316	20	97	20	0	449	12	94
PID3	2	10	50	5	75	14	17	15	190	28	124	19	5	307	21	100	19	5	510	23	106
SAP1	1	10	50	23	41	73	20	0	214	18	146	20	0	450	2	139	20	0	635	1	132
SAP1	2	10	50	5	129	16	10	50	195	32	121	2	90	579	5	180	20	0	830	16	176
SAP2	1	10	50	26	38	80	20	0	199	19	136	20	0	417	3	128	20	0	608	1	127
SAP2	2	10	50	3	0	9	10	50	147	28	91	19	5	345	21	110	19	5	708	17	150
SAP3	1	9	55	44	14	137	19	5	238	15	164	18	10	474	8	147	20	0	688	6	143
SAP3	2	19	5	4	105	13	19	5	75	108	50	19	5	185	94	55	20	0	328	82	66
Notes: %F = failure rate, calculated as N divided by total N (60 for groups, 20 for individual monitors) times 100%; %RSD = percentage of relative standard deviation; %CT = percentage of charcoal tube value.

Figure 1. Means and 95% confidence intervals of percent charcoal tube values (%CT) for individual monitors when calibration and sampling occurs at (A) cold or (B) hot conditions at either the same or different environmental conditions.

Figure 2. RMSE of percent charcoal tube values (%CT) for individual monitors when calibration and sampling occurs at the same or different environmental condition (cold and hot).