Mitigation notes

Parallel case (not today's pollutant). Pollutant: radon gas seeping into homes from the soil. Population most at risk: residents of ground-floor bedrooms in homes built on radon-rich bedrock, since they breathe the highest concentrations for the most hours.\n\nStrategy 1 (source-side): Install a sub-slab depressurization system, a vent pipe and fan that pulls radon out from under the foundation and releases it above the roof. Predicted effect: it intercepts the gas before it enters living space, so the indoor concentration and the resident's dose drop sharply and stay low. Tradeoff: it costs more up front, needs a professional to install, and the fan draws electricity continuously.\n\nStrategy 2 (receptor-side): Seal foundation cracks and run mechanical ventilation to dilute and exhaust indoor air. Predicted effect: it lowers the concentration reaching the resident, cutting dose noticeably and quickly at low cost. Tradeoff: sealing is only partial because new cracks open over time, and ventilation loses effectiveness when windows and vents are closed in cold weather.\n\nClaim: The community should begin with receptor-side sealing and ventilation now while planning source-side depressurization for the highest-reading homes.\n\nEvidence: Sealing and added ventilation are cheap and fast and produce an immediate, measurable drop in indoor radon, which protects at-risk residents this winter. Sub-slab depressurization produces a larger and more durable reduction because it removes the gas at its source, but it costs more and takes longer to install across many homes.\n\nReasoning: The best short-term risk-to-cost balance comes from the receptor-side steps, because they reduce the dose reaching people right away for very little money. Source-side depressurization is the permanent fix and gives the largest dose reduction per home, so it should run in parallel and be prioritized for the homes with the highest measured radon. Sequencing the two this way lowers exposure fastest while still moving toward the durable solution.