Ammonia concentrations are highest in the San Joaquin Valley

Dairy digesters, meant to reduce planet-warming methane emissions, significantly increase ammonia.

A map of 2020 ammonia concentrations across the United States. Zoom in on the San Joaquin Valley where more than 100 dairy digester projects are currently located.

San Joaquin

Valley

Dairy digester

projects

Ammonia concentration

1016 molecules/cm2

0

1

2

3

4+

A map of 2020 ammonia concentrations across the United States. Zoom in on the San Joaquin Valley where more than 100 dairy digester projects are currently located.

San Joaquin

Valley

Dairy digester

projects

Ammonia concentration

1016 molecules/cm2

0

1

2

3

4+

A map of 2020 ammonia concentrations across the United States. Zoom in on the San Joaquin Valley where more than 100 dairy digester projects are currently located.

Ammonia concentration

1016 molecules/cm2

0

1

2

3

4+

Dairy digester

projects

San Joaquin

Valley

Digesters shown are those funded in whole or part by the California Dairy Digester Research and Development Program

Rui Wang, Princeton University analysis of data from the Infrared Atmospheric Sounding Interferometer; California Department of Food and Agriculture

Gabrielle LaMarr LeMee LOS ANGELES TIMES