Pasadena Deploys Nine PurpleAir Sensors to Monitor Air Quality in Real Time

Caltech’s PHOENIX platform (Photo – Caltech)

In an effort to improve community health and provide transparent environmental data, the City of Pasadena has installed nine new PurpleAir FLEX air quality sensors in neighborhoods north of the 210 Freeway.

By John Boucher

The new sensors will help residents monitor pollution levels in real time—especially during wildfire season.

The initiative, led by the Pasadena Public Health Department (PPHD) at the request of the Pasadena City Council, aims to strengthen the city’s air quality monitoring network after several older sensors were destroyed by a recent wildfire. The damage limited Pasadena’s ability to track particulate matter during critical periods.

The PurpleAir FLEX sensors measure particulate matter smaller than 2.5 micrometers (PM2.5), a common pollutant linked to respiratory and cardiovascular issues. PM2.5 is especially dangerous because the particles are small enough to enter the bloodstream through the lungs, making them a key indicator of poor air quality—particularly after wildfires or high-traffic emissions.

The sensors have been installed at the following locations:

• Pasadena Public Health Department
• Playhouse Village Park
• La Pintoresca Park
• Lamanda Park Library
• Robinson Park
• Jefferson Park
• Victory Park
• Linda Vista Library
• Washington Park

These sites were selected to close data gaps in neighborhoods with higher exposure risks, including those near major truck routes.

In addition to these new sensors, PPHD continues to collect high-grade air quality data at its headquarters on North Fair Oaks Avenue through the CalTech PHOENIX network. Current readings indicate that air quality in northern Pasadena remains consistent with broader regional trends.

Residents can check current air quality by visiting PurpleAir.com. To access Pasadena’s data:

1. Click the “Map” tab at the top.
2. In the search bar, type “Pasadena, CA.”
3. Click on a sensor location to see real-time PM2.5 levels.

PPHD encourages all residents—especially those with asthma, heart conditions, or young children—to monitor the site during days with haze, wildfire smoke, or air quality alerts.