Data Gap: Air Quality Networks Miss Air Pollution from Concentrated Animal Feeding Operations

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Agricultural Science

Background:

• The agricultural sector is a major source of U.S. air pollutants, particularly ammonia (NH3).
• Livestock waste is the primary contributor to ammonia emissions.
• Satellite data indicate rising ammonia levels, unlike most controlled air pollutants.

Purpose of the Study:

• To investigate the link between increasing confined animal feeding operations (CAFOs) and rising ammonia concentrations.
• To analyze spatial and temporal trends of ammonia and animal density in the U.S.
• To assess air quality in agricultural regions relative to urban centers.

Main Methods:

• Utilized USDA data on animal numbers at medium and large CAFOs.
• Analyzed satellite-derived ammonia data from ESA's IASI and NASA's AIRS.
• Correlated summertime ammonia mixing ratios with CAFO animal unit density.
• Examined temporal trends in animal density and ammonia from 2002 to 2017.

Main Results:

• A significant positive correlation (r = 0.642, p ≈ 0) was found between summertime ammonia and CAFO animal unit density in 2017.
• Temporal changes in animal density and ammonia showed similar spatial patterns from 2002 to 2017.
• Air quality in agricultural areas with high ammonia and animal density shows slower improvement compared to urban areas.

Conclusions:

• Increasing CAFOs and associated livestock waste are driving rising ammonia levels in the U.S.
• Satellite observations confirm the impact of agricultural practices on atmospheric ammonia.
• Air quality management in agricultural regions needs to address ammonia emissions to improve PM2.5 levels.