Determining particulate matter and black carbon exfiltration estimates for traditional cookstove use in rural Nepalese village households.

A majority of black carbon (BC) emitted to the atmosphere in the Indo-Gangetic Plain (IGP) region is from burning biomass fuel used in traditional, open-design cookstoves. However, BC and particulate matter (PM) household emissions are not well characterized. Household emission information is needed to develop emission profiles to validate regional climate change models and serve as a baseline for assessing the impact of adopting improved stove technology. This paper presents field-based household PM and BC exfiltration (amount exiting) estimates from village homes in rural Nepal that utilize traditional, open-design cookstoves. Use of these stoves resulted in a 26% mean PM exfiltration, ranging from 6% to 58%. This is a significant departure from an 80% estimate cited in previous reports. Furthermore, having a window/door resulted in an 11% increase in exfiltration when an opening was present, while fuel type had a marginally significant impact on emission. Air-exchange rates (AER) were determined with average (95% CI) AER of 12 (10-14) per hour, consistent with previous studies. In addition, BC to PM2.5 mass-ratio composition during cooking was ascertained, with an average (95% CI) of 31% (24-39), agreeing with previous biomass fuel emission composition literature.