Editor’s Note: This story was updated at 1:57 p.m. Monday to reflect the re-issued alert from the Allegheny County Health Department.
The Allegheny County Health Department is investigating what caused its air quality monitor in Liberty to report erroneous data on Sunday and into Monday.
Here’s the information ACHD included in a public alert Monday morning following an inquiry from GASP about the missing data: The Allegheny County Health Department is investigating what caused its air quality monitor in Liberty to report erroneous data on Sunday and into Monday.The data during this time is not consistent with expected values. Readings for PM-10 have remained low, as was expected, and as PM-10 (particulates sized 0 .1 to 10 µm) includes PM-2.5 (particulates 0.1to 2.5 µm), the PM-10 value should always be greater than or equal to the PM-2.5 value. The PM-2.5 should have been in the green range based on the PM-10 values, not the high values being recorded.The Health Department sent a data quality analyst to the site to diagnose and hopefully repair the monitor. The monitor will be taken offline until it is repaired.The Liberty site continues to measure daily, filter-based PM-2.5 samples through a different monitor, so no data loss is expected from this temporary outage.
We will continue to follow the issue and will update you as more information becomes available.