HMMH
700 District Ave, Suite 800
Burlington, Massachusetts 01803
781.229.0707
September 27, 2021
Christine Perron
Senior Environmental Analyst
McFarland Johnson
Subject: Air Quality Conformity/NEPA Support City of Nashua
Reference: HMMH Proposal Number P21-0240
Dear Christine:
Harris Miller Miller & Hanson Inc. (HMMH) is pleased to provide McFarland Johnson with this proposal to
conduct an air quality study for the Proposed Action to address National Environmental Policy Act (NEPA)
and Transportation Conformity. HMMH will provide the air quality analysis as described below.
SCOPE OF WORK
The assessment will be conducted consistent with the National Environmental Policy Act (NEPA) including
all Federal Highway Administration (FHWA), Environmental Protection Agency (EPA), and New Hampshire
Department of Transportation (NHDOT) regulations and guidance.
1. Task 1: Traffic Data Collection
HMMH will work with the traffic engineers during their analysis to ensure appropriate traffic data are
collected for use in the air quality study.
For the carbon monoxide (CO) analysis, which is detailed below, traffic will be needed for the East Hollis
Street, Bridge Street and Ferry Street including the intersections within the study area for the Existing,
Opening and Design Year conditions including the No-Build and Build Alternative. The traffic data needed
consists of peak AM and PM hourly volumes and level of service (LOS) for the signalized intersections.
Turning movement figures along with intersection signal timing and average daily traffic (ADT) volumes
should also be included.
2. Task 2: Applicable Level of Pollutants
A project level analysis is typically conducted for operational emissions of carbon monoxide (CO),
Particulate Matter, mobile source air toxics (MSATs), volatile organic compounds (VOCs) and nitrogen
oxides (NOx). The scope of work for each pollutant is project specific and based on expected traffic
volumes (which have not been completed) and the EPA attainment status of the study area. The Project
is located in Hillsborough County which is designated as attainment for all criteria pollutants except the
2010 sulfur dioxide standard and carbon monoxide(see below).
Sulfur Dioxide: All or parts of Hillsborough, Merrimack, and Rockingham counties are designated non-
attainment for the 2010 sulfur dioxide standard. However, this status only covers the towns of Candia,
Deerfield and Northwood, which are outside the project area; therefore, Conformity for SO2 does not
apply.
