Project SPOTlight (Sensing Pollution Outdoors Together)
Monthly PurpleAir Monitor Data Report
Time Period: April 1 - April 30, 2025
Number of Monitors: 21
In April 2025, the average PM2.5 level recorded by Project SPOTlight’s PurpleAir monitors was 6.13 µg/m³. This figure includes an EPA adjustment applied to raw PurpleAir data. The adjustment is a correction developed by the EPA to improve accuracy, aligning PurpleAir readings more closely with regulatory-grade monitors.
The graph below compares averages between months going back to September 2024. Key takeaways:
- April's average was 0.95 µg/m³ lower than March’s
- PM2.5 levels rose steadily from September 2024 through December 2024, then remained elevated during the winter months.
- Daily maximum 1-hour concentrations in each household were often much higher than the monthly average and above the EPA’s annual exposure threshold, especially in winter. This suggests that even if monthly averages fall within the moderate air quality range, residents may still experience frequent short-term exposure to higher pollution levels.
The map below highlights which Project SPOTlight monitors are reporting PM2.5 levels above or below the monthly average of 6.13 µg/m³. Visualizations like this help us begin to identify whether certain areas in Beaver County are more prone to elevated PM2.5 concentrations. For comparison, the map also includes the monthly average from the Fort McIntosh monitor, operated by the Pennsylvania Department of Environmental Protection (DEP). It’s important to note that PurpleAir monitors are known to have lower accuracy than regulatory-grade monitors such as the one operated by the DEP, but are extremely helpful in filling in gaps in monitoring and providing a better understanding of regional trends.
This is the first monthly report we've released with PurpleAir data. We plan to release a similar report every month and would like to expand on what we're sharing. If you have questions about any of the data in this report, you can use this link to ask them and our team will discuss and respond. Please let us know if you have additional questions you'd like to see answered in this report. We're really interested in your feedback and thoughts!
Project SPOTlight is an EPA-funded program aimed at increasing community air quality monitoring capacity in and around Beaver County. The EPA grant is managed by the Breathe Project. Questions? Email Emily Klein at emily@breatheproject.org.