2. Some diffusion problems in the atmosphere: [8 pts] a. A point source of 1000 g of SO₂ is released. If molecular diffusion (D = 0.12 cm²/s) takes place, (1) how

long will it take to reach a standard deviation of 1 cm, 1 m and 100 m respectively, and (2) what are the maximum concentrations at these times? [2 pts each] b. C. By contrast, the molecular diffusion coefficient for a suspension of dust (1μm diameter) in air (Brownian motion) is approximately D = 2.2 x 10° cm²/s. Estimate the times now. Compare these to problem 2(a) and comment on the behavior of smog (made up of SO₂ and dust particles and other stuff!) in inversion layers over cites in which conditions are often without turbulence. [3 pts] An actual measurement during a SO₂ experimental point source release in an inversion layer shows that the half width as measured by the 10% level (i.e., where the concentration is 10% of the center point concentration) is 10 m at 1 hour after the release (see sketch). Estimate the diffusivity. Are these molecular conditions (compare to 2(a))? [3 pts] 021 44 Sxfel 10 m