chemical dynamics shape the local and regional distribution of these species.


Air quality monitoring involves measuring concentrations in the ambient air. Currently, almost all monitoring is carried out in cities; little is done in rural areas where AFOs are found. Considerations involved in establishing a monitoring program include the purposes of monitoring; the emissions of interest; analysis methods, and the precision and accuracy needed; the use of mobile versus stationary monitors; the number and locations of sampling sites; sampling frequency and averaging times; the intrusiveness of monitors; and costs.

For example, to assess the magnitude of potential health and environmental impacts of emissions from AFOs, it would be helpful to have much more data on ambient concentrations than are now available, starting perhaps with mobile monitors for substances expected to have the greatest health and environmental effects, in areas with high concentrations of livestock, and at times when emissions are expected to be greatest and meteorological conditions are not conducive to rapid vertical or horizontal dispersion (a stable atmosphere and low wind speeds).

FINDING 7. Scientifically sound and practical protocols for measuring air concentrations, emission rates, and fates are needed for the various elements (nitrogen, carbon, sulfur), compounds (e.g., NH3, CH4, H2S), and particulate matter.


  • Reliable and accurate calibration standards should be developed, particularly for ammonia.

  • Standardized sampling and compositional analysis techniques should be provided for PM, odor, and their individual components.

  • The accuracy and precision of analytical techniques for ammonia and odor should be determined, including intercomparisons on controlled (i.e., synthetic) and ambient air.


Assessment of the health and environmental effects associated with air emissions from animal feeding operations requires a substantial increase in both the accuracy of estimates of emissions of substances of interest and the accuracy of measurements of their concentrations. Concentrations are important for the determination of exposure and emission rates.

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