Acid Rain Chemistry Cross-Section (2D)

Emission Source

SO₂/NOx emission rate 55 t/day

Emission Control

Scrubber (SO₂ reduction) 0%

Atmospheric Chemistry

SO₂ → H₂SO₄ oxidized

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Rain pH

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Ecosystem Impact

Lake pH

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Fish population

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Forest health

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How it works

Burning sulfur-bearing coal and oil releases SO₂ (and NOx) from the smokestack. In the atmosphere it dissolves in cloud droplets — SO₂ + H₂O → H₂SO₃ (sulfurous acid) — and photochemical oxidants (O₃, OH radicals) slowly convert that into the much stronger H₂SO₄ (sulfuric acid): 2H₂SO₃ + O₂ → 2H₂SO₄. The longer a plume drifts before it rains out, the more of it has oxidized.

Rain pH is computed from actual hydrogen-ion concentration, not a linear fudge:

pH = -log10([H+])
[H+] = [H+]_CO2 + k · E_eff
[H+]_CO2 = 10^-5.6 M  (natural rain, dissolved CO2)
E_eff = emission · (1 - scrubber%)

Every extra unit of hydrogen ion pushes pH down logarithmically, so the first bit of pollution barely moves it while heavy, unscrubbed emission can drag rain toward pH 4 or below. A lake's natural buffering (dissolved carbonate) makes it relax toward the incoming rain's pH gradually rather than instantly, and both fish population and forest health degrade as pH falls below the ~6 threshold most freshwater species and root systems tolerate.

Scrubber slider — flue-gas desulfurization efficiency; scrubbing SO₂ before it leaves the stack cuts E_eff directly.
Oxidized % — share of the emitted SO₂ that has converted to H₂SO₄ by the time it reaches the ground.
Lake pH / Fish / Forest — slow-responding ecosystem indicators driven by the cumulative acidity of the rain falling on them.

SO₂ (unoxidized) H₂SO₄ aerosol Acid rain droplet