We
conducted indoor air quality (IAQ) measurements during a multiyear
cookstove randomized control trial in two rural areas in northern
and southern India. A total of 1205 days of kitchen PM2.5 were measured in control and intervention households during six
∼3 month long measurement periods across two study locations.
Stoves used included traditional solid fuel (TSF), improved biomass,
and liquefied petroleum gas (LPG) models. Intent-to-treat analysis
indicates that the intervention reduced average 24 h PM2.5 and black carbon in only one of the two follow-up measurement periods
in both areas, suggesting mixed effectiveness. Average PM2.5 levels were ∼50% lower in households with LPG (for exclusive
LPG use: >75% lower) than in those without LPG. PM2.5 was
66% lower in households making exclusive use of an improved chimney
stove versus a traditional chimney stove and TSF-exclusive kitchens
with a built-in chimney had ∼60% lower PM2.5 than
those without a chimney, indicating that kitchen ventilation can be
as important as the stove technology in improving IAQ. Diurnal trends
in real-time PM2.5 indicate that kitchen chimneys were
especially effective at reducing peak concentrations, which leads
to decreases in daily PM2.5 in these households. Our data
demonstrate a clear hierarchy of IAQ improvement in real world, “stove-stacking”
households, driven by different stove technologies and kitchen characteristics.