Kitchen concentrations of fine particulate matter and particle number concentration in households using biomass cookstoves in rural Honduras

Cooking and heating with solid fuels results in high levels of household air pollutants, including particulate matter (PM); however, limited data exist for size fractions smaller than PM2.5 (diameter less than 2.5 mu m). We collected 24-h time-resolved measurements of PM2.5 (n = 27) and particle number concentrations (PNC, average diameter 10-700 nm) (n = 44; 24 with paired PM2.5 and PNC) in homes with wood-burning traditional and Justa (i.e., with an engineered combustion chamber and chimney) cookstoves in rural Honduras. The median 24-h PM2.5 concentration (n = 27) was 79 mu g/m(3) (interquartile range [IQR]: 44-174 mu g/m(3)); traditional (n = 15): 130 mu g/m(3) (IQR: 48-250 mu g/m(3)); Justa (n = 12): 66 mu g/m(3) (IQR: 44-97 mu g/m(3)). The median 24-h PNC (n = 44) was 8.5 x 10(4) particles (pt)/cm(3) (IQR: 3.8 x 10(4)-1.8 x 10(5) pt/cm(3)); traditional (n = 27): 1.3 x 10(5) pt/cm(3) (IQR: 3.3 x 10(4)-2.0 x 10(5) pt/cm(3)); Justa (n = 17): 6.3 x 10(4) pt/cm(3) (IQR: 4.0 x 10(4)-1.2 x 10(5) pt/cm(3)). The 24-h average PM2.5 and particle number concentrations were correlated for the full sample of cookstoves (n = 24, Spearman rho: 0.83); correlations between PM2.5 and PNC were higher in traditional stove kitchens (n = 12, rho: 0.93) than in Justa stove kitchens (n = 12, rho: 0.67). The 24-h average concentrations of PM2.5 and PNC were also correlated with the maximum average concentrations during shorter-term averaging windows of one-, five-, 15-, and 60-min, respectively (Spearman rho: PM2.5 [0.65, 0.85, 0.82, 0.71], PNC [0.74, 0.86, 0.88, 0.86]). Given the moderate correlations observed between 24-h PM2.5 and PNC and between 24-h and the shorter-term averaging windows within size fractions, investigators may need to consider cost-effectiveness and information gained by measuring both size fractions for the study objective. Further evaluations of other stove and fuel combinations are needed. (C) 2019 Elsevier Ltd. All rights reserved.