Health: Sensors Will Allow Residents To Track Local Air Quality

CHATHAM – Given its location reaching more than 30 miles out into the Atlantic, it would seem that air quality in Chatham would be excellent, even pristine. But that’s not always the case.

 In the summer, pollution from mid-Atlantic states is often pushed over the Cape by upper level air currents, degrading air quality. And in spring and summer 2023, the east coast, including the Cape, was impacted by wildfires in Canada.

 To help track air quality, the town’s health division recently received five air quality monitors through the Massachusetts Department of Environmental Protection’s Air Sensor Grant Program. Data from the sensors will be available publicly, and since there are only three other similar sensors on the Cape — in Sandwich and Falmouth — the addition of the Chatham sensors will greatly increase the availability of air quality data for local residents, especially on the Lower and Outer Cape.

 “There’s really a kind of data gap right now,” said Natural Resources Director Greg Berman. “I think this will be a nice way of filling that gap.”

 The sensors measure particulate matter described by the federal Environmental Protection Agency as “fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller.” The particles are too small to see, but can have an impact on health, especially for those with asthma and other breathing issues. 

“These are a mixture of solid particles and liquid particles smaller even than dust, mold or pollen,” Health Agent Judy Giorgio said in an email. “They can be caused by smoke or other airborne chemicals. We hope to use the data collected to advise residents and visitors of the air quality at any given time, and provide data for the region. By strategically placing them around our community we can compare air quality as well.”

The sensors must be mounted seven to 30 feet above the ground and require a reliable electric connection and a strong WiFi signal, since they will transmit data directly to manufacturer PurpleAir. 

“These are relatively plug and play,” he said. 

An initial sensor was installed at the annex and was up and running last week. On Friday it showed an air quality of 46; 0-50 on the scale is “satisfactory.” WiFi connectivity in other locations was being tested. Berman said the preferred locations for the remaining four sensors are the transfer station, the Bassett House, the fish pier and the harbormaster’s office on Stage Harbor. 

 Once they are functional, the sensors can be monitored by residents either through PurpleAir’s website (www2.purpleair.com/) or the EPA’s AirNow fire and smoke map (www.airnow.gov/). Both maps provide real-time monitoring of hundreds of sensors in the United States and in other countries; the EPA site also provides air quality forecasts, enabling users to track the movement of pollutants.

 “It’s a nice public display,” Berman said of the maps. “You can see poor air quality coming, or reassure yourself that the air quality is good.”

 Most of the time Chatham’s air quality is likely to be rated satisfactory; the maps use a numeric and color-coded system that ranges from green (good quality) to red (poor quality), with measures of particulate matter in the air from individual stations.

 “I certainly don’t anticipate us having frequent poor air quality,” Berman said.

 Individuals can purchase sensors, which retail from $230 to $300, and contribute data to the interactive maps, Berman said.

 “This is a good example of community science,” he said. “This isn’t just for municipal use.”