Table 4 Effect of domestic filters on disinfection by-products (DBPs) concentrations in tap water.

	N ≥ LOQ	% ≥ LOQ	Min	Perc25	Perc50	Perc75	Max	Mean	SD	Average % Change
Total haloacetic acids (HAAs)
Before AC filter	6	100	2.7	14	16	32	38	21	14	−52
After AC filter	6	100	1.5	5.2	11	15	16	9.9	6.3	−52
Before RO filter	4	80	<LOQ	19	20	20	21	19	2.4	−100
After RO filter	0	0	<LOQ	<LOQ	<LOQ	<LOQ	<LOQ	<LOQ	–	−100
Total trihalomethanes (THMs)
Before AC filter	6	100	34	44	51	56	82	53	16	−80
After AC filter	6	100	0.1	6.1	11	16	20	11	7.4	−80
Before RO filter	5	100	28	35	39	46	48	39	8.0	−99
After RO filter	3	60	<LOQ	0.1	0.1	0.8	1.5	0.6	0.8	−99
Total haloacetonitriles (HANs)
Before AC filter	6	100	3.2	3.3	3.5	3.7	4.7	3.6	0.6	−75
After AC filter	5	83	<LOQ	0.4	0.7	1.2	1.8	0.9	0.6	−75
Before RO filter	5	100	2.2	2.7	3.9	4.0	4.2	3.4	0.9	−100
After RO filter	0	0	<LOQ	<LOQ	<LOQ	<LOQ	<LOQ	<LOQ	–	−100
1,1,1-trichloropropanone (TCP)
Before AC filter	3	50	<0.01	0.8	1.1	1.1	1.2	0.9	0.4	−63
After AC filter	1	17	<0.01	0.3	0.3	0.3	0.3	0.3	0	−63
Before RO filter	1	17	<0.01	1.3	1.3	1.3	1.3	1.3	0	−100
After RO filter	0	0	<0.01	<0.01	<0.01	<0.01	<0.01	<0.01	–	−100
Chlorite
Before AC filter	5	83	<10	16.8	17.2	119	142	61.2	63.8	−60
After AC filter	3	50	<10	17.0	17.0	28.4	39.7	24.5	13.1	−60
Before RO filter	2	40	<10	22.6	22.6	22.6	22.6	22.6	0	−100
After RO filter	0	0	<10	<10	<10	<10	<10	<10	–	−100
Chlorate
Before AC filter	6	100	153	193	219	314	367	248	86.3	−27
After AC filter	6	100	116	144	178	185	296	181	62.9	−27
Before RO filter	4	80	<10.0	167	183	232	341	217	84.4	−98
After RO filter	5	100	18.2	28.1	34.2	35.5	44.4	32.1	9.70	−98

Number of samples (N, %) with DBPs above the limit of quantification (LOQ) and concentrations (µg/L) in tap water before and after activated carbon (AC, N = 6) and reverse osmosis (RO, N = 5) filters.

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