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Region 1: EPA New England

MASSACHUSETTS

For 1999 and after, click on the date for the corresponding eight-hour average peak ozone map for that day.

In March 2008, EPA revised the 8-hour ozone standard and changed the Air Quality Index (AQI) to align with this new standard. Maps for days in 2007 and earlier are based on the 1997 8-hour ozone standard. Maps for 2008 are based on the new 2008 ozone standard and the revised AQI. Click Here for a table showing the revised AQI breakpoints for the 2008 ozone standard.

Adams | Agawam | Amherst | Bue Hill | Boston - Long Island | Chelmsford | Chelsea | Chicopee | Easton | North Easton | Fairhaven | Haverhill | Lawrence | Lynn | Martha's Vineyard | Newbury | Newburyport | Scituate | Stow | Sudbury | Truro | Uxbridge | Waltham | Ware | Worcester

Adams
Operating from 1995 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 0 2 0.079 May 31 0.078 Aug 4 0.074 May 30 0.074 Aug 9
1995 0 2 0.083 June 18 0.077 Aug 1 0.073 June 19 0.072 June 29
1996 2 6 0.096 June 7 0.085 Aug 7 0.084 June 2 0.081 June 1
1997* 1 5 0.090 June 30 0.084 July 13 0.082 July 14 0.078 June 12
1998* 0 1 0.076 May 29 0.074 July 14 0.073 Sept 15 0.069 Sept 14
1999 1 3 0.086 May 31 0.083 June 1 0.080 July 16 0.075 June 24
2000* 1 2 0.090 June 10 0.078 June 11 0.075 May 6 0.072 June 9
2001 16 26 0.108 June 19 0.099 June 20 0.093 May 4 0.092 June 14
2002 4 10 0.101 Aug 14 0.096 Aug 13 0.091 Aug 12 0.086 Aug 11
2003 2 8 0.104 June 26 0.100 June 25 0.083 June 27 0.083 July 2
2004 1 2 0.086 July 22 0.081 June 24 0.075 Aug 10 0.071 July 1
2005 6 11 0.091 June 9 0.089 Sept 13 0.087 June 24 0.087 June 25
2006 0 4 0.082 June 18 0.079 June 19 0.077 Aug 14 0.076 June 17
2007 2 11 0.093 June 8 0.086 May 25 0.082 May 24 0.080 Sept 7
2008 2 2 0.100 June 13 0.092 June 14 0.075 July 12 0.072 May 26
2009 0 2 0.083 May 22 0.079 May 21 0.075 May 20 0.066 June 6
2010 0 1 0.080 Sep 2 0.074 July 4 0.074 Sep 1 0.073 July 5
2011 1 1 0.088 July 20 0.071 July 21 0.068 July 17 0.067 June 8
2012 0 0 0.074 June 21 0.074 Aug 31 0.073 April 16 0.073 July 12
2013 0 1 0.076 May 31 0.074 June 1 0.067 Aug 20 0.066 Aug 21

*Site did not meet 75% minimum data completeness requirement.

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Agawam
Operating from 1982 to 2002
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 8 14 0.103 July 20 0.100 Aug 4 0.090 Aug 25 0.089 Aug 1
1995 6 14 0.109 July 13 0.096 June 30 0.096 Sept 7 0.093 July 4
1996 2 5 0.087 Aug 8 0.085 July 8 0.084 Aug 7 0.082 July 12
1997 9 11 0.097 July 1 0.094 Aug 11 0.093 June 21 0.092 July 25
1998 1 5 0.093 Aug 24 0.082 July 14 0.081 July 16 0.080 July 15
1999 1 8 0.088 June 1 0.084 May 31 0.083 July 30 0.081 Aug 17
2000 1 2 0.089 June 10 0.080 June 16 0.073 June 26 0.071 June 2
2001 2 7 0.091 June 19 0.086 July 23 0.082 July 22 0.081 June 20
2002 6 13 0.118 Aug 14 0.112 Aug 13 0.101 Aug 12 0.097 July 22

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Amherst
Operating from 1988 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 7 12 0.097 July 9 0.097 Aug 4 0.096 June 17 0.091 July 20
1995 3 7 0.089 Aug 31 0.085 Sept 7 0.085 June 30 0.084 July 28
1996 3 7 0.087 July 12 0.086 Aug 8 0.085 July 8 0.081 Aug 7
1997 2 7 0.098 July 1 0.092 Aug 11 0.083 July 27 0.082 Aug 10
1998 2 8 0.100 July 14 0.096 July 16 0.083 July 27 0.081 July 28
1999 3 10 0.098 July 31 0.089 June 1 0.085 June 27 0.084 May 31
2000 1 2 0.086 June 10 0.082 June 16 0.066 June 25 0.065 June 1
2001 3 10 0.102 June 19 0.086 June 20 0.085 June 13 0.084 May 4
2002 4 8 0.107 Aug 14 0.096 Aug 13 0.091 July 22 0.086 June 21
2003 0 0 0.069 June 29 0.066 April 16 0.061 June 27 0.061 July 24
2004 1 3 0.088 July 22 0.079 Aug 10 0.076 June 24 0.062 June 8
2005 1 5 0.092 June 9 0.079 June 25 0.078 April 20 0.078 June 8
2006 1 2 0.102 June 19 0.078 July 27 0.075 July 10 0.074 Aug 14
2007 3 9 0.094 July 10 0.091 July 9 0.087 Aug 30 0.080 June 19
2008 0 1 0.078 April 19 0.075 June 10 0.074 April 18 0.073 May 30
2009 0 1 0.076 April 27 0.073 Aug 20 0.071 May 22 0.070 July 16
2010 0 1 0.077 Sep 2 0.074 May 1 0.070 May 2 0.069 Sep 7
2011 0 0 0.074 July 21 0.068 June 28 0.066 July 20 0.061 June 11
2012 0 1 0.082 July 13 0.073 May 29 0.068 May 13 0.068 July 12
2013 0 0 0.067 April 28 0.063 June 1 0.060 June 22 0.059 April 30

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Blue Hill
Operating from 2002 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
2002 17 32 0.134 Aug 13 0.116 Aug 12 0.112 Aug 14 0.107 Sept 9
2003 5 7 0.109 June 27 0.091 June 26 0.090 June 25 0.089 Aug 22
2004 2 6 0.100 June 8 0.095 June 17 0.084 July 30 0.078 June 9
2005 4 15 0.103 June 25 0.091 June 24 0.090 April 20 0.089 June 26
2006 2 7 0.087 July 18 0.086 June 18 0.084 June 19 0.083 July 2
2007 7 14 0.095 July 26 0.095 Aug 3 0.094 May 25 0.088 Aug 30
2008 0 4 0.082 June 10 0.078 June 14 0.077 July 19 0.076 April 23
2009 0 3 0.081 April 28 0.081 May 22 0.076 Aug 18 0.071 May 21
2010 0 2 0.083 July 5 0.081 Sep 2 0.075 July 21 0.073 Sep 1
2011 0 1 0.076 July 21 0.075 June 8 0.073 July 6 0.073 July 11
2012 0 2 0.080 July 17 0.078 June 29 0.075 Aug 31 0.074 Aug 9
2013 0 0 0.075 July 19 0.074 May 31 0.072 Sept 11 0.071 June 25

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Boston - Long Island
Operating from 1999 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1999 4 10 0.102 July 16 0.100 June 24 0.089 June 1 0.087 May 31
2000 0 1 0.084 June 10 0.073 June 1 0.072 Aug 9 0.070 June 2
2001 9 13 0.111 June 20 0.107 June 19 0.100 Aug 2 0.094 July 24
2002 10 18 0.126 Aug 13 0.117 Aug 14 0.102 July 3 0.102 Sept 9
2003 1 4 0.102 June 27 0.083 June 25 0.078 June 26 0.078 July 4
2004 1 5 0.094 June 8 0.081 July 22 0.080 July 23 0.079 July 30
2005 5 9 0.095 June 25 0.091 June 26 0.089 Aug 11 0.086 June 24
2006 0 5 0.083 June 22 0.083 July 2 0.083 July 18 0.079 July 1
2007 0 3 0.082 Sept 25 0.080 April 23 0.076 Sept 26 0.073 Aug 3
2008 0 1 0.083 June 10 0.073 July 3 0.072 July 18 0.072 July 26
2009 0 3 0.081 April 28 0.080 May 22 0.076 May 21 0.075 Aug 18
2010 0 1 0.079 Sep 2 0.074 July 21 0.071 Sep 1 0.070 July 28
2011 0 1 0.077 July 21 0.074 July 11 0.069 July 6 0.066 July 17
2012 1 1 0.085 July 17 0.070 July 15 0.069 July 11 0.067 April 16
2013 0 2 0.077 May 31 0.076 July 19 0.072 Sept 11 0.071 June 25

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Chelmsford
Operating from 2005 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
2005 2 8 0.095 June 27 0.085 June 25 0.080 April 20 0.079 June 24
2006 0 2 0.083 June 19 0.077 June 22 0.073 Mar 31 0.071 June 18
2007 5 9 0.095 Aug 30 0.091 Aug 3 0.089 May 25 0.087 June 27
2008 0 1 0.079 July 3 0.071 April 23 0.071 July 8 0.069 June 10
2009 0 1 0.076 May 22 0.073 May 21 0.069 Aug 18 0.068 April 28
2010 0 1 0.079 Sep 2 0.074 July 28 0.069 July 16 0.069 Aug 9
2011 1 1 0.086 July 21 0.074 July 11 0.068 June 8 0.064 May 27
2012 1 1 0.089 July 17 0.075 July 13 0.073 Aug 4 0.072 Aug 9
2013 0 0 0.071 July 19 0.071 Sept 11 0.067 April 29 0.067 June 22

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Chelsea
Operating from 1984 to 1999
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 3 3 0.089 June 18 0.086 June 17 0.086 Aug 9 0.074 July 19
1995 1 9 0.101 Aug 1 0.084 July 13 0.083 June 30 0.083 Aug 10
1996 0 0 0.075 July 12 0.073 Aug 9 0.072 Aug 7 0.071 Aug 6
1997 2 3 0.086 June 30 0.085 Aug 10 0.081 June 21 0.075 June 12
1998 4 7 0.095 Aug 24 0.088 May 29 0.088 July 14 0.087 July 15
1999 3 8 0.102 July 16 0.093 July 17 0.089 June 24 0.084 May 31

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Chicopee
Operating from 1983 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 8 17 0.102 Aug 4 0.102 July 20 0.097 June 17 0.095 Aug 1
1995 8 17 0.101 July 13 0.100 June 30 0.095 July 4 0.093 July 28
1996 3 6 0.094 July 8 0.094 Aug 7 0.087 Aug 8 0.082 July 12
1997 7 10 0.104 July 1 0.097 Aug 11 0.095 June 21 0.092 July 27
1998 5 14 0.104 July 16 0.102 July 14 0.097 July 15 0.093 Aug 24
1999 7 15 0.095 June 1 0.093 July 30 0.089 July 16 0.088 June 27
2000 1 4 0.090 June 10 0.084 June 16 0.084 June 26 0.079 June 2
2001 9 18 0.105 June 19 0.098 June 20 0.097 May 4 0.090 May 2
2002 10 20 0.118 Aug 14 0.115 Aug 12 0.108 July 22 0.108 Aug 13
2003 3 8 0.099 June 25 0.093 June 29 0.089 June 27 0.084 June 26
2004 1 4 0.093 July 22 0.083 Aug 10 0.080 June 24 0.078 May 15
2005 8 15 0.104 June 9 0.098 Aug 12 0.095 June 26 0.090 June 25
2006 5 11 0.119 June 19 0.102 June 18 0.091 June 22 0.090 July 27
2007 8 18 0.112 July 9 0.109 July 10 0.102 Aug 3 0.098 Aug 30
2008 2 6 0.086 June 10 0.085 June 28 0.080 July 26 0.078 April 19
2009 0 4 0.080 May 22 0.078 Aug 20 0.077 April 27 0.076 Aug 18
2010 1 2 0.091 Sep 2 0.078 July 28 0.075 May 1 0.074 May 2
2011 0 2 0.081 July 21 0.076 July 11 0.075 July 20 0.074 June 21
2012 0 2 0.084 July 13 0.076 July 17 0.075 May 29 0.074 Sept 14
2013 0 1 0.082 Sept 11 0.072 May 31 0.072 June 1 0.071 June 22

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Easton
Operating from 1996 to 2001
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1996 3 8 0.094 July 6 0.087 Aug 7 0.085 Aug 23 0.084 June 17
1997 7 13 0.096 June 30 0.095 June 12 0.094 July 17 0.093 June 21
1998 7 11 0.105 Aug 24 0.091 July 15 0.090 Sept 6 0.088 Sept 27
1999 3 8 0.091 June 24 0.089 July 16 0.086 July 17 0.083 July 15
2000 0 2 0.081 May 7 0.077 July 3 0.074 June 9 0.072 June 10
2001 14 25 0.107 Aug 2 0.103 Aug 9 0.101 June 20 0.098 June 19

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North Easton
Operating from 1982 to 1996
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 8 16 0.103 Aug 9 0.102 June 18 0.098 July 13 0.098 July 20
1995 10 20 0.108 Aug 1 0.108 Aug 2 0.106 Aug 10 0.104 July 14
1996 1 3 0.085 July 6 0.078 June 17 0.076 Aug 7 0.075 Aug 23

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Fairhaven
Operating from 1982 to 2011, relocated and restarted in 2013
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 1 4 0.098 July 13 0.080 Aug 4 0.080 Aug 28 0.077 July 12
1995 9 14 0.125 June 19 0.124 Aug 21 0.107 June 18 0.107 July 14
1996 6 14 0.113 July 18 0.104 June 14 0.092 May 20 0.092 July 6
1997 12 18 0.107 July 14 0.106 July 17 0.103 Aug 2 0.092 Aug 3
1998 2 12 0.099 Sept 6 0.087 May 28 0.084 Aug 4 0.083 Aug 3
1999 8 14 0.112 July 16 0.109 June 7 0.101 June 23 0.098 July 6
2000 3 8 0.105 June 10 0.090 July 2 0.085 Aug 8 0.082 May 7
2001 8 16 0.117 Aug 7 0.113 Aug 9 0.109 May 4 0.101 Aug 2
2002 5 15 0.105 July 2 0.102 July 18 0.087 July 1 0.087 July 3
2003 8 15 0.117 June 27 0.101 Aug 16 0.100 June 26 0.098 June 25
2004 1 7 0.099 June 9 0.084 June 8 0.082 May 11 0.080 July 4
2005 1 9 0.086 Aug 11 0.084 April 20 0.084 Aug 2 0.082 June 8
2006 4 8 0.107 July 18 0.104 Aug 1 0.093 Aug 2 0.085 July 17
2007 1 3 0.086 May 25 0.083 July 8 0.082 Aug 2 0.075 June 28
2008 2 4 0.088 July 18 0.085 July 17 0.082 July 19 0.080 June 10
2009 0 1 0.078 Aug 18 0.072 Aug 26 0.071 Aug 4 0.069 May 21
2010 0 5 0.081 July 5 0.079 July 17 0.078 July 6 0.077 June 24
2011 1 4 0.085 June 7 0.081 July 16 0.080 June 8 0.076 July 22
2013* 0 1 0.087 July 18 0.067 July 19 0.067 Aug 21 0.064 July 20

*Site did not meet 75% minimum data completeness requirement.

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Haverhill
Operating from 2004 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
2004 1 3 0.091 July 22 0.078 July 23 0.078 July 30 0.072 Aug 10
2005 0 4 0.084 Sept 14 0.079 June 25 0.079 July 26 0.078 June 24
2006 1 2 0.089 June 19 0.081 June 22 0.075 July 25 0.075 July 26
2007 6 11 0.096 Aug 3 0.095 Aug 30 0.092 May 25 0.090 June 27
2008 1 3 0.093 June 10 0.084 July 3 0.083 July 8 0.073 April 23
2009 0 0 0.075 Aug 18 0.074 May 22 0.073 May 21 0.070 Aug 4
2010 0 1 0.076 Sep 2 0.074 July 28 0.072 Sep 1 0.071 July 16
2011 1 1 0.086 July 21 0.075 July 11 0.075 June 8 0.066 May 27
2012 1 3 0.089 July 17 0.079 July 13 0.079 Aug 9 0.074 Aug 17
2013 0 0 0.069 June 1 0.068 June 22 0.068 July 19 0.068 Sept 11

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Lawrence
Operating from 1982 to 2002
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 2 5 0.096 June 18 0.087 July 21 0.084 Aug 9 0.082 July 20
1995 0 1 0.077 July 13 0.074 Aug 9 0.071 June 30 0.069 July 5
1996 1 7 0.085 Aug 8 0.081 July 12 0.080 Aug 4 0.079 June 2
1997 2 4 0.108 July 1 0.088 Aug 11 0.081 Aug 10 0.078 July 27
1998 1 4 0.088 Aug 24 0.081 July 16 0.077 July 14 0.076 May 29
1999 1 2 0.088 June 1 0.083 May 31 0.075 June 2 0.068 June 6
2000 0 0 0.067 June 16 0.062 June 10 0.062 May 4 0.060 Aug 9
2001 0 0 0.073 June 19 0.066 June 20 0.063 June 14 0.062 July 24
2002 6 13 0.109 Aug 12 0.105 Aug 13 0.102 Aug 14 0.088 June 21

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>
Lynn
Operating from 1993 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 6 14 0.097 June 17 0.096 June 18 0.094 July 21 0.090 Aug 9
1995 7 17 0.116 Aug 1 0.100 July 13 0.098 Aug 10 0.094 June 30
1996 2 9 0.091 Aug 9 0.085 Aug 23 0.083 July 8 0.083 Aug 7
1997 6 11 0.104 July 1 0.096 June 30 0.093 June 21 0.091 Aug 10
1998 7 11 0.108 Aug 24 0.105 July 15 0.103 May 29 0.100 July 14
1999 6 14 0.109 July 16 0.101 June 24 0.096 July 17 0.088 May 31
2000 1 1 0.089 June 10 0.073 June 1 0.073 July 3 0.070 Aug 9
2001 11 17 0.111 June 20 0.102 Aug 2 0.101 July 24 0.100 July 23
2002 13 25 0.123 Aug 13 0.122 Aug 14 0.109 June 26 0.100 July 9
2003 3 6 0.100 June 27 0.092 Aug 22 0.088 June 25 0.079 June 26
2004 2 6 0.092 June 8 0.088 July 30 0.083 July 23 0.083 Aug 3
2005 6 11 0.099 June 25 0.096 June 26 0.094 June 24 0.088 July 26
2006 1 5 0.086 June 19 0.084 June 18 0.079 June 22 0.078 July 18
2007 4 13 0.103 Aug 3 0.102 July 26 0.093 May 25 0.088 June 27
2008 1 5 0.086 July 18 0.081 June 10 0.079 July 3 0.078 July 8
2009 0 2 0.079 May 22 0.077 Aug 18 0.073 April 28 0.073 May 21
2010 0 1 0.083 Sep 2 0.075 Aug 9 0.075 Sep 1 0.072 July 28
2011 1 1 0.085 July 21 0.075 July 11 0.074 July 6 0.069 June 7
2012 1 2 0.091 July 17 0.076 July 15 0.074 July 13 0.072 June 29
2013 0 2 0.078 July 19 0.078 Sept 11 0.074 May 31 0.073 June 25

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Martha's Vineyard
Operating from 2004 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
2004 0 1 0.078 July 4 0.074 June 23 0.074 July 22 0.072 June 30
2005 4 11 0.106 Aug 11 0.104 Aug 2 0.088 Sept 12 0.087 June 5
2006 4 6 0.112 Aug 1 0.112 Aug 2 0.101 Aug 3 0.089 July 29
2007 3 4 0.094 May 26 0.091 May 25 0.088 June 17 0.077 April 23
2008 3 5 0.101 June 9 0.100 July 29 0.087 July 17 0.083 June 10
2009 0 1 0.078 Aug 26 0.075 May 20 0.074 May 21 0.071 Aug 18
2010 2 6 0.100 July 4 0.086 July 18 0.081 Aug 31 0.080 Sep 1
2011 2 5 0.113 July 22 0.093 June 8 0.082 June 7 0.078 July 23
2012 2 8 0.100 June 21 0.094 June 20 0.083 June 29 0.082 July 14
2013 0 1 0.079 July 18 0.071 July 16 0.065 June 24 0.065 June 25

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Newbury
Operating from 1994 to 2009
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 0 4 0.084 Aug 26 0.084 Aug 28 0.082 Aug 25 0.077 Sept 17
1995 3 8 0.101 Aug 10 0.098 June 30 0.092 Aug 1 0.083 July 5
1996 2 8 0.087 Aug 6 0.085 July 8 0.084 Aug 8 0.083 July 12
1997 6 9 0.106 June 30 0.104 July 1 0.087 June 21 0.087 July 27
1998 6 7 0.103 May 29 0.096 July 16 0.096 Aug 5 0.089 July 14
1999 6 9 0.112 July 16 0.108 June 24 0.089 May 31 0.087 July 23
2000 0 1 0.082 June 1 0.074 July 2 0.074 July 3 0.071 June 21
2001 8 16 0.117 June 20 0.099 June 19 0.095 June 15 0.093 July 24
2002 9 18 0.126 Aug 14 0.120 Aug 13 0.103 Aug 12 0.094 June 21
2003 2 7 0.099 June 27 0.092 June 25 0.082 April 15 0.080 Aug 22
2004 1 5 0.085 July 30 0.084 July 23 0.079 Aug 3 0.077 June 8
2005 0 5 0.083 July 22 0.082 June 26 0.079 April 20 0.078 Aug 8
2006 1 3 0.086 June 19 0.082 June 18 0.078 June 22 0.075 July 15
2007 4 9 0.097 Aug 3 0.094 July 26 0.086 May 25 0.086 Sept 7
2008 1 3 0.085 July 18 0.080 June 10 0.077 July 26 0.075 July 3
2009 0 2 0.078 May 22 0.077 May 21 0.072 April 28 0.068 April 25

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Newburyport
Operating from July 2010 to present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
2010 0 1 0.079 Sept 1 0.074 July 28 0.067 July 21 0.066 July 16
2011 0 1 0.082 July 21 0.074 July 11 0.068 June 7 0.066 June 9
2012 0 2 0.082 July 17 0.080 July 13 0.075 Aug 23 0.074 June 22
2013 0 0 0.074 June 21 0.073 Aug 21 0.073 Sept 11 0.071 June 1

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Scituate
Operating from 1987 to 1997
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 2 6 0.088 July 13 0.087 Aug 9 0.082 July 20 0.082 July 21
1995 1 4 0.089 Aug 1 0.084 June 18 0.084 July 14 0.081 Aug 10
1996 0 0 0.073 July 6 0.067 Aug 6 0.064 Sept 4 0.063 July 16
1997 1 3 0.088 July 14 0.080 June 30 0.080 July 1 0.071 July 17

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Stow
Operating from 1998 to 2011
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1998 5 8 0.109 May 29 0.098 Aug 24 0.090 July 14 0.090 July 15
1999 8 14 0.096 July 16 0.095 Aug 17 0.094 July 30 0.093 June 1
2000 1 2 0.099 June 10 0.077 June 2 0.075 May 7 0.073 July 13
2001 12 17 0.105 June 19 0.101 July 23 0.101 July 24 0.098 June 20
2002 8 16 0.110 Aug 13 0.107 Aug 12 0.106 Aug 14 0.096 June 26
2003 0 3 0.083 June 27 0.079 June 26 0.077 June 24 0.073 June 29
2004 1 1 0.085 June 8 0.075 July 22 0.071 July 23 0.070 June 24
2005 2 5 0.091 June 25 0.087 June 24 0.084 July 26 0.083 April 20
2006 0 3 0.084 June 18 0.083 June 19 0.076 June 22 0.075 May 25
2007 5 10 0.091 Aug 3 0.091 Aug 30 0.086 May 25 0.086 Sept 7
2008 1 2 0.090 June 14 0.076 July 3 0.075 June 10 0.074 July 8
2009 0 3 0.082 May 22 0.078 May 21 0.077 April 28 0.071 April 25
2010 0 1 0.077 Sep 2 0.070 May 22 0.070 Aug 9 0.069 July 7
2011 0 1 0.077 July 21 0.066 July 11 0.063 Apr 10 0.063 July 17

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Sudbury
Operating from 1982 to 1998
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 7 15 0.111 Aug 9 0.099 July 20 0.096 July 21 0.093 Aug 4
1995 8 16 0.111 Aug 1 0.094 June 30 0.092 July 13 0.091 Sept 7
1996 2 7 0.090 July 12 0.090 Aug 7 0.084 Aug 8 0.084 Aug 9
1997 6 10 0.106 July 1 0.094 June 30 0.090 June 12 0.088 June 21
1998 4 8 0.104 Aug 24 0.091 May 29 0.086 July 14 0.085 July 15

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Truro
Operating from 1987 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 4 11 0.096 July 13 0.092 Aug 4 0.090 Aug 28 0.088 Aug 1
1995 9 16 0.125 June 19 0.122 July 14 0.122 Aug 21 0.105 June 18
1996 8 15 0.110 May 21 0.106 June 14 0.100 July 6 0.096 Aug 7
1997* 17 24 0.110 Aug 2 0.106 June 30 0.104 June 12 0.100 June 11
1998 2 10 0.110 Sept 2 0.086 May 28 0.084 Aug 5 0.084 Sept 12
1999 12 19 0.116 June 7 0.115 July 16 0.104 July 17 0.101 June 24
2000 3 10 0.126 June 10 0.094 June 9 0.091 Aug 8 0.083 July 2
2001 13 15 0.124 Aug 7 0.113 May 4 0.108 Aug 9 0.105 Aug 2
2002 9 17 0.112 Aug 13 0.105 July 2 0.105 July 18 0.093 Aug 14
2003 8 16 0.110 June 27 0.094 June 25 0.094 July 5 0.089 Aug 16
2004 3 6 0.107 June 9 0.089 June 8 0.085 May 11 0.083 July 30
2005 7 15 0.095 Aug 11 0.094 Aug 5 0.088 April 19 0.088 April 20
2006 3 12 0.106 Aug 1 0.104 July 18 0.098 Aug 2 0.082 June 19
2007 2 13 0.093 May 25 0.085 June 26 0.082 May 24 0.082 July 25
2008 2 3 0.106 June 10 0.086 July 18 0.082 July 19 0.075 July 2
2009 0 2 0.082 Aug 18 0.078 Aug 26 0.073 May 20 0.071 May 22
2010 1 4 0.086 June 24 0.079 July 17 0.079 Aug 31 0.078 Sep 2
2011 0 0 0.074 June 8 0.073 July 22 0.071 July 16 0.068 June 7
2012 2 6 0.088 June 30 0.085 Aug 31 0.080 June 22 0.079 June 29
2013 0 3 0.079 May 30 0.076 June 25 0.076 July 19 0.072 May 31

*Site did not meet 75% minimum data completeness requirement.

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Uxbridge
Operating from 2009 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
2009 1 2 0.086 April 28 0.082 May 22 0.073 May 21 0.071 Aug 18
2010 0 1 0.077 Sep 2 0.074 Aug 9 0.074 Sep 22 0.071 May 22
2011 0 3 0.076 July 11 0.076 July 6 0.074 July 21 0.068 June 8
2012 1 1 0.086 July 17 0.071 Sept 13 0.070 May 13 0.070 Aug 3
2013 0 0 0.074 July 19 0.070 May 31 0.070 Sept 11 0.068 April 28

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Waltham
Operating from 1989 to 1999
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 2 11 0.098 Aug 9 0.091 July 20 0.083 Aug 4 0.082 July 19
1995 5 16 0.107 Aug 1 0.093 June 30 0.090 May 24 0.090 Sept 7
1996 1 3 0.086 Aug 7 0.080 July 12 0.076 June 7 0.074 Aug 26
1997 6 11 0.106 July 1 0.095 June 21 0.093 June 30 0.092 Aug 11
1998 7 17 0.116 Aug 24 0.100 July 15 0.099 July 14 0.098 May 29
1999 5 13 0.104 July 16 0.098 June 24 0.091 June 1 0.091 July 17

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Ware
Operating from 1986 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 10 21 0.110 July 20 0.109 Aug 4 0.097 Aug 25 0.095 April 15
1995 7 13 0.110 June 30 0.101 July 13 0.097 Aug 31 0.096 Sept 7
1996 4 5 0.095 Aug 7 0.093 Aug 8 0.091 July 8 0.085 July 12
1997 9 22 0.119 June 25 0.117 July 1 0.115 June 21 0.110 Aug 11
1998 6 14 0.110 May 29 0.102 July 16 0.101 July 14 0.093 Aug 24
1999 9 13 0.106 Aug 17 0.102 June 1 0.094 July 24 0.094 July 31
2000 2 5 0.091 June 10 0.089 June 16 0.080 July 3 0.076 June 2
2001 12 23 0.119 June 19 0.116 June 20 0.099 July 23 0.093 May 4
2002 10 17 0.110 Aug 14 0.107 Aug 13 0.096 Aug 11 0.095 June 21
2003 0 3 0.084 June 25 0.080 June 29 0.077 June 26 0.075 July 2
2004 3 8 0.091 Aug 10 0.090 July 22 0.086 Aug 3 0.083 June 24
2005 8 12 0.101 June 9 0.096 June 8 0.091 June 25 0.090 July 26
2006 4 10 0.110 June 19 0.103 June 18 0.098 June 22 0.086 Aug 7
2007 7 15 0.113 July 9 0.102 Aug 3 0.093 Aug 30 0.087 Aug 29
2008 1 7 0.095 June 10 0.082 April 19 0.079 May 30 0.079 July 8
2009 0 4 0.079 April 27 0.079 May 22 0.077 April 25 0.076 May 21
2010 1 5 0.089 Sep 2 0.084 July 28 0.077 May 1 0.076 May 2
2011 0 1 0.084 July 21 0.075 July 11 0.075 July 20 0.066 June 21
2012 0 4 0.079 July 17 0.077 Aug 17 0.076 May 13 0.076 Sept 13
2013 0 0 0.075 May 31 0.073 June 1 0.069 April 28 0.069 June 22

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Worcester
Operating from 1992 to Present
Year # Days > 1st High (ppm) Date 2nd High (ppm) Date 3rd High (ppm) Date 4th High (ppm) Date
0.084 0.075
1994 11 20 0.107 Aug 9 0.102 Aug 4 0.098 Aug 25 0.097 July 7
1995 7 15 0.108 Sept 7 0.106 July 13 0.101 Aug 31 0.096 June 30
1996 0 2 0.080 July 12 0.078 Aug 7 0.074 June 6 0.074 June 7
1997 5 8s 0.097 July 1 0.095 June 30 0.094 Aug 11 0.092 Aug 10
1998 6 14 0.123 Aug 24 0.109 July 15 0.103 May 29 0.097 July 14
1999 8 14 0.101 June 24 0.098 Aug 17 0.096 July 16 0.093 June 1
2000 1 4 0.095 June 10 0.081 July 13 0.077 June 2 0.076 Aug 9
2001 6 9 0.102 June 19 0.097 July 24 0.093 July 23 0.091 Aug 9
2002 8 14 0.118 Aug 13 0.102 Aug 12 0.097 Sept 10 0.091 Aug 11
2003 1 9 0.089 June 27 0.084 June 29 0.080 June 25 0.080 July 12
2004 0 3 0.082 June 8 0.082 July 22 0.076 Aug 10 0.074 June 24
2005 5 8 0.092 June 25 0.090 April 20 0.087 June 24 0.085 June 9
2006 2 5 0.091 June 19 0.091 June 22 0.083 Aug 7 0.077 May 25
2007 10 20 0.096 June 27 0.095 Aug 3 0.090 June 25 0.089 May 25
2008 2 8 0.104 June 14 0.089 July 3 0.084 July 8 0.081 June 10
2009 0 4 0.082 May 22 0.082 Aug 18 0.080 May 21 0.077 April 28
2010 0 3 0.083 Sep 2 0.078 Aug 9 0.077 July 28 0.070 July 16
2011 1 2 0.089 July 21 0.078 July 11 0.066 May 31 0.065 July 6
2012 1 1 0.092 July 17 0.074 Sept 13 0.072 Aug 17 0.070 July 14
2013 0 0 0.074 May 31 0.070 June 1 0.070 Sept 11 0.067 April 28

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