Abstract
Ultrafine particle (UFP) emissions and particle number size distributions (PNSD) are critical in the evaluation of air pollution impacts; however, data on UFP number emissions from cookstoves, which are a major source of many pollutants, are limited. In this study, 11 fuel-stove combinations covering a variety of fuels and different stoves are investigated for UFP emissions and PNSD. The combustion of LPG and alcohol (∼10(11) particles per useful energy delivered, particles/MJ(d)), and kerosene (∼10(13) particles/MJ(d)), produced emissions that were lower by 2-3 orders of magnitude than solid fuels (10(14)-10(15) particles/MJ(d)). Three different PNSD types-unimodal distributions with peaks ∼30-40 nm, unimodal distributions with peaks <30 nm, and bimodal distributions-were observed as the result of both fuel and stove effects. The fractions of particles smaller than 30 nm (F(30)) varied among the tested systems, ranging from 13% to 88%. The burning of LPG and alcohol had the lowest PM(2.5) mass emissions, UFP number emissions, and F(30) (13-21% for LPG and 35-41% for alcohol). Emissions of PM(2.5) and UFP from kerosene were also low compared with solid fuel burning but had a relatively high F(30) value of approximately 73-80%.