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  3. Moss Landing Vistra Battery Fire
  4. Frequently Asked Questions

Moss Landing Air: Is there a difference between air monitoring and air sampling?

Return to: Frequently Asked Questions

Yes. Monitoring and sampling are used to accomplish different goals.

Air monitoring gives immediate results. Air monitoring at the site occurs continuously and shows patterns and changes in the air in real time. The air is monitored for PM2.5, PM10, and hydrogen fluoride gas. Monitoring will show us if immediate action is necessary..

Air sampling takes physical samples of the air which are sent to an independent laboratory for analysis. Sampling looks at what was in the air over the entire day. Sample results provide us with an average daily concentration of contaminants.

These results are more accurate than air monitoring results because more analysis is done. The time it takes to do this analysis, however, takes longer. Sampling results are systematically validated by the laboratory, which reviews quality control information for each sample.

The air is sampled for aluminum, asbestos fibers, cobalt, copper, manganese, and nickel.

For more information about community safety, see our  EPA Factsheet: Keeping the Community Safe (pdf) (466.79 KB, January 2026) .

Related Questions

  • Moss Landing Air: What air monitoring activities did you do during the January 2025 fire response?
  • Moss Landing Air: What air monitoring/sampling is required during Vistra's battery removal work?
  • Moss Landing Air: How are air results evaluated?

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Last updated on April 14, 2026
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