Predicted brightness temperature for the 4₀₄−3₁₃ line of SO₂ at 29.321 GHz for different sets of collisional rates. The assumed kinetic temperature and Δv= are 10 K and 1 km s^-1, respectively. Black(thin)/red(thick) lines correspond to the excitation of the molecule by o-H₂/p-H₂ using the collisional rates calculated in this work. Blue dotted lines correspond to the predicted intensity when the rates of Green (1995) for the SO₂-He system are used. Column densities are indicated and correspond to 3  ×  10¹⁴, 10¹⁴, 3  ×  10¹³, and 10¹³ cm^-2.