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| Read About Estimated Risk | 
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| Year | Months Present | Minimum | Median | Mean | 90th Percentile | Maximum | Standard Deviation | Number of Observations | Detection Limit | Estimated Risk | ||||||||||||
| 2025 | 
 | 0.2 | 0.5 | * | 1.3 | 1.4 | 0.40 | 12 | 0.1 | * | ||||||||||||
| 2024 | 
 | 0.2 | 0.5 | 0.60 | 1.0 | 1.4 | 0.31 | 31 | 0.1 | 9 | ||||||||||||
| 2023 | 
 | 0.1 | 0.5 | 0.49 | 0.7 | 0.9 | 0.20 | 29 | 0.1 | 7 | ||||||||||||
| 2022 | 
 | 0.1 | 0.4 | 0.46 | 0.8 | 0.9 | 0.20 | 31 | 0.1 | 7 | ||||||||||||
| 2021 | 
 | 0.3 | 0.5 | * | 0.8 | 1.4 | 0.30 | 17 | 0.1 | * | ||||||||||||
| 2020 | 
 | 0.2 | * | * | * | 0.9 | 0.24 | 8 | 0.1 | * | ||||||||||||
| 2019 | 
 | 0.2 | 0.4 | 0.47 | 0.8 | 1.2 | 0.27 | 29 | 0.1 | 7 | ||||||||||||
| 2018 | 
 | 0.2 | 0.5 | 0.57 | 0.9 | 1.4 | 0.27 | 31 | 0.1 | 8 | ||||||||||||
| 2017 | 
 | 0.2 | 0.5 | 0.62 | 1.1 | 1.5 | 0.35 | 30 | 0.1 | 9 | ||||||||||||
| 2016 | 
 | 0.2 | 0.8 | * | 1.4 | 2.1 | 0.46 | 27 | 0.1 | * | ||||||||||||
| 2015 | 
 | 0.3 | 0.7 | 0.72 | 1.1 | 1.7 | 0.32 | 30 | 0.1 | 10 | ||||||||||||
| 2014 | 
 | 0.1 | 0.5 | 0.57 | 1.1 | 1.2 | 0.30 | 31 | 0.1 | 8 | ||||||||||||
| 2013 | 
 | 0.3 | 0.5 | 0.54 | 0.9 | 1.8 | 0.32 | 30 | 0.1 | 8 | ||||||||||||
| 2012 | 
 | 0.3 | 0.7 | 0.75 | 1.3 | 1.6 | 0.34 | 30 | 0.1 | 11 | ||||||||||||
| 2011 | 
 | 0.2 | 0.8 | * | 1.2 | 1.5 | 0.33 | 28 | 0.1 | * | ||||||||||||
| 2010 | 
 | 0.4 | 0.7 | 0.72 | 1.1 | 1.3 | 0.27 | 25 | 0.1 | 11 | ||||||||||||
| 2009 | 
 | 0.2 | 0.7 | 0.78 | 1.3 | 1.8 | 0.36 | 31 | 0.1 | 12 | ||||||||||||
| 2008 | 
 | 0.3 | 0.7 | 0.72 | 1.2 | 1.5 | 0.32 | 30 | 0.1 | 11 | ||||||||||||
| 2007 | 
 | 0.3 | 0.6 | 0.70 | 1.3 | 2.0 | 0.40 | 30 | 0.1 | 10 | ||||||||||||
| 2006 | 
 | 0.1 | 0.7 | 0.71 | 1.1 | 1.9 | 0.40 | 31 | 0.1 | 10 | ||||||||||||
| 2005 | 
 | 0.3 | 0.7 | 0.86 | 1.5 | 1.9 | 0.46 | 30 | 0.1 | 13 | ||||||||||||
| 2004 | 
 | 0.05 | 0.6 | 0.74 | 1.2 | 1.9 | 0.39 | 30 | 0.1 | 11 | ||||||||||||
| 2003 | 
 | 0.2 | 0.7 | 0.72 | 1.1 | 1.3 | 0.32 | 31 | 0.1 | 11 | ||||||||||||
| 2002 | 
 | 0.3 | 0.6 | 0.75 | 1.2 | 1.6 | 0.37 | 31 | 0.1 | 11 | ||||||||||||
| 2001 | 
 | 0.3 | 0.8 | 0.78 | 1.1 | 1.8 | 0.34 | 29 | 0.1 | 11 | ||||||||||||
| 2000 | 
 | 0.2 | 0.7 | 0.75 | 1.1 | 1.9 | 0.41 | 27 | 0.1 | 11 | ||||||||||||
| 1999 | 
 | 0.2 | 0.8 | 0.91 | 1.6 | 2.9 | 0.60 | 30 | 0.1 | 13 | ||||||||||||
| 1998 | 
 | 0.05 | 0.6 | 0.70 | 1.2 | 2.3 | 0.46 | 30 | 0.1 | 10 | ||||||||||||
| 1997 | 
 | 0.4 | 0.8 | 0.91 | 1.5 | 2.2 | 0.39 | 30 | 0.1 | 13 | ||||||||||||
| 1996 | 
 | 0.2 | 0.7 | 0.83 | 1.3 | 2.5 | 0.47 | 30 | 0.1 | 12 | ||||||||||||
| 1995 | 
 | 0.05 | 0.5 | 0.64 | 1.3 | 2.0 | 0.56 | 27 | 0.1 | 9 | ||||||||||||
| 1994 | 
 | 0.4 | 1.3 | 1.32 | 2.0 | 3.1 | 0.57 | 30 | 0.1 | 19 | ||||||||||||
| 1993 | 
 | 0.1 | 1.1 | 1.16 | 1.8 | 2.6 | 0.67 | 29 | 0.1 | 17 | ||||||||||||
| 1992 | 
 | 0.2 | 0.9 | 0.99 | 1.9 | 2.2 | 0.58 | 27 | 0.1 | 14 | ||||||||||||
| 1991 | 
 | 0.2 | 1.0 | 1.21 | 2.0 | 2.2 | 0.60 | 29 | 0.1 | 18 | ||||||||||||
| 1990 | 
 | 0.2 | 1.0 | 1.10 | 1.7 | 2.9 | 0.69 | 34 | 0.1 | 16 | ||||||||||||
| 1989 | 
 | 0.6 | 1.0 | 1.33 | 2.3 | 3.1 | 0.66 | 25 | 0.1 | 20 | ||||||||||||
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| 1989-1995 data and 1996-2025 data represent different methods and should not be compared. | |||
| See Report on a Parallel Carbonyl Monitoring Study Using C18 and Silica Gel Sampling Media for details. | |||
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|  | 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. |  |