Household Smoke from Solid-Fuel Cooking: A Low-Cost Chimney Hood Priced by Draft Physics

A chimney hood over an open cooking fire is sized from stack-effect draft physics (3.5 m flue, 200 mm diameter: draft 12.02 Pa, effective flow 0.0689 m3/s) and coupled to a well-mixed room box model with published PM2.5 emission rates. In a 22.5 m3 kitchen the hood reduces modelled session-mean cook exposure by 66.3%, a solar exhaust fan by 63.5% and an improved-combustion stove by 59.1%; ranked by reduction per dollar the fan ranks first (1.411 %/USD), the stove second (1.182) and the hood third (1.053). The chimney fails against adverse wind above about 5.39 m/s, at cold start, and under flue temperature inversion; height, ridge clearance and an anti-downdraft cowl are the stated partial margins. Design study: SIMULATED, NOT MEASURED.