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New Hampshire Monitoring Values and Trajectories October 27, 2011



# New Hampshire’s 8-Hour Ozone Monitoring Values and

Airmass Trajectories

Updated New Hampshire ozone data and design values for the period of 2009 through 2011 are detailed

in the table below. All 8-hour ozone design valu es in New Hampshire continue to measure well below

the ozone National Ambient Air Quality Standard (NAAQS) of 75 parts per billion (ppb).



## 2009 – 2011 8-Hour Ozone Design Values by Monitor, parts-per-billion (ppb)

Location Monitor

ID 2009-11

Design Value 2009

4 th Max 2010

4 th Max 2011

4 th Max

Camp Dodge 330074002 59 58 59 59

Concord 330131007 66 64 68 65

Keene 330050007 63 62 64 62

Laconia 330012004 62 62 64 60

Lebanon 330090010 60 59 61 59

Londonderry 330150018

-- -- -- 69

Manchester 330110020

-- 60 63

--

Miller State Park 330115001 70 72 77 62

Mt. Washington Summit 330074001 69 68 73 67

Nashua 330111011 66 66 67 65

Portsmouth 330150014 67 70 66 64

Rye - Odiorne 330150016 67 68 66 66



## Areas of Influence to Regional Monitors with Design Values

Greater than 75 ppb in Massachusetts and Rhode Island

NHDES performed airflow back-trajectory analyses fo r all monitors that exceeded the ozone NAAQS

during either of the most recent two design valu e periods (2008-2010 and 2009-2011). There are no

monitors in New Hampshire, Maine, or Vermont with design values that fall into this category, but there

are two in Massachusetts (Martha’s Vineyard and Wor cester) and one in Rhode Island (Narragansett) that

qualify. For this analysis, back-trajectories were modeled for any day that one of the three identified

monitors exceeded 75 ppb during 2009, 2010, or 2011.

NHDES used the National Oceanic and Atmospheric Administration (NOAA)’s Air Resources

Laboratory HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model. This is a

computer model designed to create and map trajectories using gridded historical meteorological data. All

trajectories produced by NHDES begin 72 hour s before a measured value exceeds 75ppb.

Each set of figures show that none of the airflow back trajectories pass over New Hampshire prior to

arriving at Martha’s Vineyard, Worcester, or Na rragansett during high ozone days. Instead the

trajectories show a strong influence from the southern portion of the Northeast Urban Corridor. Since

none of these trajectories pass over New Hampshire and because New Hampshire’s ozone levels are

safely below the 75 ppb NAAQS, it can be concluded th at New Hampshire does not contribute to any of

these exceedances in southeastern Mass achusetts and Rhode Island and fu rther supports the concept that

these areas are in a different airshed from New Hampshire.Technical Attachment Page A-2

New Hampshire Monitoring Values and Trajectories October 27, 2011



## Back Trajectories for Days Greate r than 75 ppb at Worcester, MATechnical Attachment Page A-3

New Hampshire Monitoring Values and Trajectories October 27, 2011Technical Attachment Page A-4

New Hampshire Monitoring Values and Trajectories October 27, 2011Technical Attachment Page A-5

New Hampshire Monitoring Values and Trajectories October 27, 2011



## Back Trajectories for Days Greater th an 75 ppb at Martha’s Vineyard, MATechnical Attachment Page A-6

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New Hampshire Monitoring Values and Trajectories October 27, 2011Technical Attachment Page A-9

New Hampshire Monitoring Values and Trajectories October 27, 2011Technical Attachment Page A-10

New Hampshire Monitoring Values and Trajectories October 27, 2011



## Back Trajectories for Days Greate r than 75 ppb at Narragansett, RITechnical Attachment Page A-11

New Hampshire Monitoring Values and Trajectories October 27, 2011Technical Attachment Page A-12

New Hampshire Monitoring Values and Trajectories October 27, 2011