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  2. EPA in California
  3. Moss Landing Vistra Battery Fire
  4. Frequently Asked Questions

Moss Landing Air: What happened with the spike in particulate matter at air monitoring station 9 the morning of January 18, which resulted in a 1.275 mg/m3 reading for PM10?

Return to: Frequently Asked Questions

EPA contractors were servicing the equipment at station 9, which resulted in a false reading of a temporary spike in PM10 at that location.

Some temporary spikes or gaps in the data are expected, due to various factors such as lapses in telemetry (data transmission), instrument batteries dying (because of running 24/7 operations in the field remotely), and routine maintenance. For example, if the transmission of data to the database is not paused during equipment servicing, it can result in false elevated readings.

EPA investigated this particular elevated reading and then reviewed the equipment service logs from EPA contractors. EPA determined the data does not indicate sustained elevated readings of particulate matter (PM) 10, and that the equipment was being serviced at this time. EPA looks for sustained patterns of elevated readings to assess air quality impacts. There is sufficient data to show that particulate matter concentrations from the fire were not exceeding human health standards.

Related Questions

  • Moss Landing Air: What air monitoring activities did you do during the January fire response?
  • Moss Landing Air: What were the results of EPA's air monitoring from January 17 to 20?
  • Moss Landing Air: What did you test for during the fire?
  • Moss Landing Air: What air monitoring technology did you use?
  • Moss Landing Air: Are you requiring any air monitoring or sampling during Vistra’s battery removal work?
  • Moss Landing Air: Is there a difference between air monitoring and air sampling?
  • Moss Landing Air: What particulate sizes did EPA monitor during the initial response in January?
  • Moss Landing Air: Can you detect nanoparticles in the air with the instrumentation you used during the initial response?

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Last updated on September 29, 2025
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