Model-predicted gas phase DMS concentrations (ppb) at 08:00 h, 12:00 h, 16:00 h, and 20:00 h with sulfur fossil fuel emissions, boundary conditions, and initial conditions for SO2 and H2SO4 set to zero. (A) Only urban OSC emission sources including DMS emissions from humans and DMS, DMDS, and MTO from pet waste. (B) Urban and agriculture OSC emission sources (same conditions as A plus DMS and DMDS emissions from Chino, California). (C) Urban, agriculture, and ocean OSC emission sources (same conditions as B plus DMS from ocean).