Citizen Air Monitoring Program

Monitoring for fine particulate matter throughout New Hampshire using PurpleAir sensors.

Fine particulate matter (PM2.5) is one of the most pervasive and widespread air pollutants in New Hampshire. These small particles come from many sources, but woodsmoke is the primary driver for elevated concentrations in the Granite State due to the common practice of burning wood for residential heating. Though considerable progress has been made in reducing PM2.5 from woodsmoke, largely in part to newer EPA certified wood stoves entering the market, there still exists room for continued improvement. In order to make additional progress in lowering PM2.5 levels, it is important to understand what current levels are, which can be done through monitoring. Currently, there are six PM2.5 monitoring stations throughout New Hampshire that are owned and operated by NHDES, but there are many areas of the state that are not covered by this monitoring.

Thanks to modern technology and initiatives to improve air quality, effective low-cost air quality sensors have come into the market, including PurpleAir monitors. PurpleAir is a private company that makes air quality sensors available for the public, measuring PM2.5 and providing local air quality data at an affordable cost. The unit is easy to install, and information is uploaded every 10 minutes to an online, publicly available map. Data provided can help households, businesses and municipalities better understand their local air quality.

NHDES Partnership

NHDES has created a voluntary program that allows PurpleAir owners to register their outdoor unit(s) with our agency to become part of a subgroup of distinguished citizen scientists that have their data quality assured by NHDES air quality officials. Due to these sensors being publicly available, it is not always known, for instance, whether they were installed properly or whether there is influence from local emissions sources. By registering sensors with NHDES, owners would gain access to installation suggestions, maintenance tips, and the knowledge that their data is part of a network that is regularly reviewed by state air pollution authorities. This free service ensures that the data being collected is as accurate and beneficial as possible.

Registering with NHDES can provide:

  • Help with PurpleAir registration, installment and maintenance.
  • A user-friendly, New Hampshire-specific, PurpleAir map for the registered units.
  • Air quality data that has been reviewed by state air pollution officials.

A snapshot of the NHDES registration formRegistration with NHDES is free and provides data review by state air quality officials as well as installation and maintenance tips. By registering with NHDES, you will help fill in monitoring gaps throughout the Granite State while becoming a part of a network of units that is regularly reviewed by state authorities all at no extra cost.

Become a citizen scientist  


A picture of what the map looks likeThis map shows air quality data in New Hampshire from PurpleAir units that have been reviewed by state officials. The data is in real time and in a user-friendly format that is updated every 10 minutes. This map is free to the public and, with your help, NHDES can provide access to quality assured data while filling in monitoring gaps.

NHDES Sensor Map  


Looking for archived fine particulate matter data that has been reviewed by NHDES?

Here you can request archived data from our network of PurpleAir units around the state. Please contact Marcus Chase to receive any archived data.