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	Annual Toxics Summary Chula Vista FAQs Zirconium nanograms per cubic meter

Year	Months Present	Minimum	Median	Mean	90th Percentile	Maximum	Standard Deviation	Number of Observations	Detection Limit
2025		0.65	1.7	*	2.9	7.5	1.85	12	1.3
2024		0.65	0.65	1.52	3.3	4.8	1.21	30	1.3
2023		0.65	1.4	1.88	4.0	5.6	1.40	31	1.3
2022		0.65	0.65	1.57	3.8	4.5	1.26	31	1.3
2021		0.65	0.65	*	3.3	6.0	1.47	23	1.3
2020		0.65	*	*	*	3.6	1.16	8	1.3
2019		0.65	0.65	1.69	3.6	5.2	1.26	30	1.3
2018		0.65	0.65	1.61	3.6	4.0	1.23	31	1.3
2017		0.65	1.6	1.79	3.6	5.3	1.35	30	1.3
2016		0.65	1.8	*	4.1	6.7	1.62	27	1.3
2015		0.65	0.65	1.47	3.1	5.8	1.33	30	1.3
2014		0.75	0.75	1.19	2.4	4.1	0.92	31	1.5
2013		0.75	0.75	*	2.0	3.5	0.69	28	1.5
2012		0.75	0.75	0.92	1.7	2.6	0.51	29	1.5
2011		0.75	0.75	*	0.75	2.7	0.44	25	1.5
2010		0.75	0.75	*	0.75	4.3	0.76	25	1.5
2009		0.75	0.75	1.22	1.8	11	1.88	30	1.5
2008		*	*	*	*	*	*	0	*
2007		0.75	0.75	0.98	1.6	3.7	0.63	29	1.5
2006		*	*	*	*	*	*	0	*
2005		*	*	*	*	*	*	0	*
2004		*	*	*	*	*	*	0	*
2003		3.0	*	*	*	9.0	2.49	5	2.0
2002		1	3.0	3.49	6.1	12	2.44	30	2.0
2001		1	2.0	2.38	4.6	8.0	1.90	28	2.0
2000		1	2.0	*	5.0	6.0	1.81	11	2.0
1999		1	2.0	*	3.4	6.0	1.39	17	2.0
1998		1	1	2.13	5.0	9.0	1.96	27	2.0
1997		1	3.0	2.43	4.0	5.0	1.37	29	2.0
1996		1	1	1.63	3.1	5.0	1.13	30	2.0
1995		1	2.0	2.15	4.0	6.0	1.35	29	2.0
1994		1	1	1.99	3.1	5.0	1.12	30	2.0
1993		1	2.0	3.21	6.0	15	2.96	27	2.0
1992		1	1	2.10	4.3	10	1.99	28	2.0
1991		1	2.0	2.13	4.0	7.0	1.41	29	2.0
1990		1	3.0	*	6.0	16	3.64	16	2.0
1989		*	*	*	*	*	*	0	*

	Notes:	Values below the Limit of Detection (LoD) assumed to be ½ LoD. Means and risks shown only for years with data in all 12 months. "*" means there was insufficient or no data available to determine the value.