Field based measurement of multiple pollutant emissions from residential coal burning in rural Shanxi, northern China

It was well recognized that the pollutant emissions from real-world residential coal combustion contributed significantly to air pollution and human health, resulting in an urgent need for a better understanding of the pollutant emission factors (EFs) of residential coal combustion. However, field-based researches on residential coal combustion emissions are still limited at this stage. In this study, based on carbon balance method, emission factors (EFs) of CO2 and a series of pollutants, including gaseous pollutants (CO, NOX, CH4, and SO2), particulate matters (PM2.5 and PM10), elemental carbon (EC), organic carbon (OC), and polycyclic aromatic hydrocarbons (PAHs) from residential honeycomb briquette (HB) and coal chunk (CC) combustions were measured in real world cooking stoves. As a result, apart from SO2, the burning of HB produced much less pollutants than CC. The median of emission reduction ratios estimated from Monte Carlo simulation ranged from 2.4% (SO2) to 98.8% (EC) by replacing CC with HB in residential combustion in Shanxi province in 2012. EFs of CO, PM2.5 and PAHs derived from the present field measurement were around 1-50 times higher than those from laboratory tests; furthermore, larger variations were found in our field measurement compared to that in the laboratory studies. This result called for more field measurements to reduce uncertainties of emission inventory estimations. As for the PAH emissions, particle phase PAHs dominated in both HB and CC burning and PAH emissions from HB burning had lower toxicity than CC combustion. Hence, HB is an ideal substituted fuel compared with CC. Previous studies suggested that PAH isomer ratios of FLA/(FLA+PYR) and IcdP/(IcdP+BghiP) above 0.5 represented source of coal combustion, which did not fit with our study well, indicating PAH isomer ratios might not be valid enough for source apportionment.