We knew it in principle and now we know it in fact: fuel-based lighting emitsindoor pollutants (in the form of particularly dangerous "PM2.5" particulates) that can be inhaled deeply into lungs of over a billion people that use such light sources.

Kerosene lamps are often located in close proximity to users, potentially increasing the risk for respiratory illnesses and lung cancer. Particulate matter concentrations resulting from cook stoves have been extensively studied in the literature. However, characterization of particulate concentrations from fuel- based lighting has received minimal attention.

Using actual measurements, our  research—published by the Lumina team in the journal Indoor Air — demonstrates that night vendors who use a single simple wick lamp in high-air-exchange market kiosks will likely be exposed to dangerous PM2.5 concentrations that are an order of magnitude greater than ambient health guidelines. Particles of this size (2.5 microns in diameter) are known to penetrate particularly deeply into the lungs when inhaled.

We found that using a hurricane lamp will reduce exposure to PM2.5 and PM10 concentrations by an order of magnitude compared to using a simple wick lamp. Vendors using a single hurricane or pressure lamp may not exceed health standards or guidelines for PM2.5 and PM10, but will be exposed to elevated 0.02–0.3 micrometer particle concentrations. Vendors who change from fuel-based lighting to electric lighting technology for enhanced illumination will likely gain the ancillary health benefit of reduced particulate matter exposure.

We found that vendors exposed only to ambient and fuel-based lighting particulate matter would see over an 80% reduction in inhaled PM2.5 mass if they switched from a simple wick lamp to an electric lighting technology.

A more recent review of the literature of indoor air pollution from kerosene lanterns (as well as other health effects) was recently published by Nick Lam and colleagues (here).