Starting July 8 parking at Brookline Village will be limited due to the Pierce School construction.

Please note: The Brookline Village Library will be closed on Sundays from June 16 to September 1.

CO2 Monitor & Air Quality Information

How to Use Your Co2 Monitor

Aranet4 devices 

The real time data is visible on the face of the monitor. If you’d like to view or download a graph of the readings, you can connect the device to your Bluetooth-enabled phone or tablet. It is often more useful to observe trends over time than a single value as room air fluctuates over time.

Steps to connect to the Aranet4 app

  1. Download the Aranet4 app from the app store or google play store – Bluetooth must be enabled
  2. Tap Pair New Device
  3. Select the device and enter the code on the front of the device
  4. Your device will now begin reading the air quality.

Tips for the most accurate reading

  • Take the device outdoors in an open area away from crowds. After a few minutes the reading should be between 400-450 ppm, that means it’s properly calibrated.
    If the device is not properly calibrated, follow the instructions in the user manual: Aranet4 user manual 
  • Always take readings at least 2m away from people’s faces or your readings may be artificially high.
  • Readings should be performed when the space is occupied. If you expect 30 people in the room, you’ll want to take a reading with 30 people present.
  • You may notice the readings stay steady, rise continuously, or cycle from higher to lower values. These patterns provide hints to how the space is ventilated and may guide your troubleshooting to improve ventilation in the space.

Indoor air quality resources

Carbon Dioxide Monitoring for Indoor Air Quality, from the Toronto Public Library

Carbon Dioxide Monitoring for Indoor Air Quality, from Peterborough Public Health in collaboration with the Peterborough Public Library

Eykelbosh, A. (2021). Indoor CO2 Sensors for COVID-19 Risk Mitigation: Current Guidance and Limitations (ISBN: 978-1-988234-58-8). National Collaborating Centre for Environmental Health.

Poppendieck, D. (n.d.). Consumer IAQ Monitors. Retrieved November 4, 2021, from

Rhode Island Department of Health. (n.d.). Preventing the spread of COVID by circulating air in schools and other buildings. Retrieved August 18, 2022, from

Nelson, A. (2022, March 23). Let’s Clear The Air On COVID. The White House Office of Science and Technology Policy Briefing Room Blog.

CDC. (n.d.). Interactive Ventilation Tool. Retrieved February 9, 2022, from

Public Health Agency of Canada. (2021, March 19). COVID-19: Improving indoor ventilation [Education and awareness].