Emission of PAHs, NPAHs and OPAHs from residential honeycomb coal briquette combustion

TLDR

Coal combustion is a major source of air pollution in China. The study aimed to determine emission factors of PAHs, NPAHs, and OPAHs in five coals of differing geological maturity burned as honeycomb briquettes. Emission factors were measured in coals with vitrinite reflectance 0.77–1.88 % using honeycomb briquettes. EFs ranged from 9.8–215 mg kg⁻¹ for PAHs, 0.14–1.88 mg kg⁻¹ for NPAHs, and 4.5–20.8 mg kg⁻¹ for OPAHs, were lowest for anthracite, increased with geological maturity, and projected 2007 residential emissions were 4.36 Gg PAHs, 0.03 Gg NPAHs, 0.47 Gg OPAHs, falling to 2.18 Gg, 0.02 Gg, 0.24 Gg by 2020, with anthracite use potentially reducing emissions by 93 %, 87 %, and 71 % respectively.

Abstract

Coal combustion is one of the most significant sources of air pollution in China. In this study, emission factors (EFs) of 15 polycyclic aromatic hydrocarbons (PAHs), 26 nitrated PAHs (NPAHs) and 6 oxygenated PAHs (OPAHs) were determined in five different coals with different geological maturity (vitrinite reflectance RO = 0.77–1.88%) burned in the form of honeycomb briquettes. The total EFs ranged from 9.82 to 215 mg kg–1 for PAHs, 0.14 to 1.88 mg kg–1 for NPAHs and 4.47 to 20.8 mg kg–1 for OPAHs. Measured EFs and gas-particle partitioning varied depending on the geological maturity. The lowest EFs were found in anthracite. The proportion of PAHs, NPAHs and OPAHs in gaseous phase increasing with increased geological maturity. The coal with higher geological maturity produced more 3-ring PAHs. On the basis of the statistical analysis for the residential sector of China in 2008, PAHs, NPAHs and OPAHs emitted from residential honeycomb coal briquettes were 4.36 Gg, 0.03 Gg and 0.47 Gg in 2007, respectively. By 2020, the emission would decrease to 2.18 Gg, 0.02 Gg and 0.24 Gg for PAHs, NPAHs and OPAHs due to the increasing usage of new energy resources. If only anthracite is used as the residential coal, 93% PAHs, 87% NPAHs and 71% OPAHs would be reduced in 2020.