California dominates U.S. emissions of the pesticide and potent greenhouse gas sulfuryl fluoride

Abstract

Sulfuryl fluoride (SO₂F₂) is a synthetic pesticide and a potent greenhouse gas that is accumulating in the global atmosphere. Rising emissions are a concern since SO₂F₂ has a relatively long atmospheric lifetime and a high global warming potential. The U.S. is thought to contribute substantially to global SO₂F₂ emissions, but there is a paucity of information on how emissions of SO₂F₂ are distributed across the U.S., and there is currently no inventory of SO₂F₂ emissions for the U.S. or individual states. Here we provide an atmospheric measurement-based estimate of U.S. SO₂F₂ emissions using high-precision SO₂F₂ measurements from the NOAA Global Greenhouse Gas Reference Network (GGGRN) and a geostatistical inverse model. We find that California has the largest SO₂F₂ emissions among all U.S. states, with the highest emissions from southern coastal California (Los Angeles, Orange, and San Diego counties). Outside of California, only very small and infrequent SO₂F₂ emissions are detected by our analysis of GGGRN data. We find that California emits 60-85% of U.S. SO₂F₂ emissions, at a rate of 0.26 ( ± 0.10) Gg yr⁻¹. We estimate that emissions of SO₂F₂ from California are equal to 5.5–12% of global SO₂F₂ emissions.

Despite stringent efforts to reduce greenhouse gas emissions, California is the largest emitter of sulfuryl fluoride in the USA, according to atmospheric measurements and an inverse model.