Biochar is charcoal made by pyrolysing biomass with little oxygen; its
internal surface area (hundreds of m² per gram) physically adsorbs CO₂ and
locks the carbon away for centuries once mixed into a block. Hempcrete works
similarly through the hemp shiv's own captured biomass carbon plus a
lime binder that slowly re-carbonates. Standard concrete's cement binder has
no such pore chemistry and is a net emitter from clinker production.
capture_rate ∝ porosity × surface_area × flux
saturation(t) = 1 − e^(−k·t) (Langmuir-style adsorption)
net_balance = embodied_emissions − captured_CO2
- Porosity — fraction of the block's volume that is open pore space; more pores means more surface for gas to stick to.
- Ambient CO₂ flux — how much CO₂-laden air reaches the block's surface (wind, exposure).
- Material toggle — biochar-crete and hempcrete both capture; standard concrete instead has a small constant outgassing shown as red particles.
- Pause — freezes the gas-exchange animation to inspect the pore network.