High loadings of carbonaceous aerosols from wood smoke in the atmosphere of Beijing from 2015 to 2017: Implications for energy transition policy.

Recently, biomass has been regarded as a promising option for solid energy in China, which is promoted in the residential sector and firing power plants. We collected 200 PM2.5 samples (particulate matter with a aerodynamic diameter smaller than 2.5 µm) at multi-sites across Beijing from three individual sampling cases from 2015 to 2017. The levels of OC, OC fractions, EC, EC fractions, as well as K+ were measured. Then, we adopted the Positive Matrix Factorization 5.0 to apportion the sources of carbonaceous aerosols. The source apportionment results were compared with the estimates of source contribution using the bottom-up technical method with the latest emission inventories after the Action Plan was put into effect in 2013. Our results demonstrate that high pollution of carbonaceous aerosols originated from wood smoking based on the receptor modeling and bottom-up technical method in Beijing from 2015 to 2017. Future energy transition policy should focus on the technologies and regulations for reducing emissions from renewable biomass fuel combustion. This study highlights the importance of regulations that address emissions controls on fuels replacing coal combustion to meet the needs to mitigate air pollution from primary energy use.

Cell cycle arrest of human bronchial epithelial cells modulated by differences in chemical components of particulate matter.

There is increasing interest in understanding the role of airborne chemical components in modulating the cell cycle of human bronchial epithelial (HBE) cells that is associated with burden of cardiopulmonary disease. To address this need, our study collected ambient PM10 (particles with aerodynamic diameter less than or equal to 10 µm) and PM2.5 (particles with aerodynamic diameter less than or equal to 2.5 µm) across four sampling sites in Beijing during the year of 2015. Chemical components including organic carbon (OC), elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), metals and water soluble ions were determined. Spearman's rank-order correlation was performed to examine the associations between chemical components in ambient particles and cell cycle distributions with p-values adjusted by Bonferroni methodology. Our results demonstrated the significant associations between certain chemical compositions (i.e., PAHs, EC, As and Ni) and percentages of HBE cells in G0/G1 and G1/G2 phases, respectively. Our results highlighted the need to reduce the specific toxins (e.g., PAHs, EC, As and Ni) from ambient particles to protect cardiopulmonary health associated with air pollution. Future study may focus on illustrating the mechanism of certain chemical compositions in altering the cell cycle in HBE cells.

[Vertical distribution of PBDEs and DL-PCBs in sediments of Taihu Lake].

Sediment core samples collected from the Zhushan Bay, Meiliang Bay, South Taihu of Taihu Lake were analyzed for 8 polybrominated diphenylethers (PBDEs) and 12 dioxin-like PCBs (DL-PCBs). The results revealed that the PBDEs levels were highest in the Zhushan Bay, followed by Meiliang Bay and South Taihu; and the DL-PCB levels were highest in the Meiliang Bay, followed Zhushan Bay and South Taihu. The vertical distribution of PBDEs level showed an exponential growth trend in Taihu Lake sediments, BDE-209 was the most abundant PBDEs congeners; and the vertical distribution of the DL-PCBs level in the sediments revealed that the contamination caused by DL-PCBs continued to increase in recent years, indicating that there were PCBs sources in the Taihu Lake region. There was significant difference in the composition of PBDEs congeners at different depths in the sediments of Meiliang Bay, however, the detailed causes remain to be investigated in further studies. The vertical distribution pattern of PCBs congeners revealed that PCB-77, -118, -105 levels significantly decreased with increasing depth in 0-15 cm upper sediments and there chang in the lower sediments.