Indoor and outdoor PM2.5 and CO in high- and low-density Guatemalan villages.

Continuous particles less than 2.5 microm in diameter (PM2.5) and carbon monoxide (CO) were monitored during breakfast, lunch, and dinner in three high-density and four low-density villages near Quetzaltenango, Guatemala to help assess the viability of this region for a proposed respiratory health and stove intervention study. Approximately 15 homes were visited during each mealtime in each of the seven villages; in all, 98 homes were visited, with a sampling duration of 2-3 min per home per meal. For each village, a line (transect) was drawn on a village map along existing roads from one end of the village to the other; homes and between-home outside locations along the transect were monitored. Although the predominant stove type was the open fire, several other stoves, in various levels of disrepair, were observed frequently. The highest indoor concentrations of PM2.5 were observed in homes using the open fire (avg. = 5.31 mg/m3; SD=4.75 mg/m3) or equivalent, although homes using the plancha--indigenous wood-burning stove with chimney--also had measurements > 13.8 mg/m3, PM2.5 limit of detection. The highest indoor concentrations of CO were also observed in homes using the open fire (avg. = 22.9 ppm; SD = 28.1 ppm), with a maximum measurement of > 250 ppm. For both PM2.5 and CO, levels measured in homes with plancha, lorena, or open fire were significantly higher than levels taken in the street or in homes using a gas stove. The Spearman correlation coefficient between PM2.5 and CO for all data combined was 0.81, and ranged from 0.30 for the lorena to 0.68 for the plancha in homes using wood-fueled stoves. Although indoor PM2.5 and CO levels were not significantly different between high- and low-density villages, street-level PM2.5 (p = 0.002) and CO (p= 0.002), were significantly higher in the high - density villages. These data provide a useful picture of the pollution levels coming from a range of cooking stoves in various levels ofdisrepair, as well as a representation of how outdoor particle mass and CO levels vary from high- versus low-density villages.