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 Operating from 1995 to Present
Year	# Days >		1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
*Site did not meet 75% minimum data completeness requirement. Top of Page

Agawam Operating from 1982 to 2002
Year	# Days >		1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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 Present
Year	# Days >		1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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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Newbury Operating from July 2010 to Present
Year	# Days >		1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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 Present
Year	# Days >		1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
*Site did not meet 75% minimum data completeness requirement. Top of Page

Uxbridge Operating from 2009 to Present
Year	# Days >		1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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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
Year	0.084	0.075	1st High (ppm)	Date	2nd High (ppm)	Date	3rd High (ppm)	Date	4th High (ppm)	Date
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
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