Morphology, composition, and mixing state of primary particles from combustion sources - crop residue, wood, and solid waste.

Morphology, composition, and mixing state of individual particles emitted from crop residue, wood, and solid waste combustion in a residential stove were analyzed using transmission electron microscopy (TEM). Our study showed that particles from crop residue and apple wood combustion were mainly organic matter (OM) in smoldering phase, whereas soot-OM internally mixed with K in flaming phase. Wild grass combustion in flaming phase released some Cl-rich-OM/soot particles and cardboard combustion released OM and S-rich particles. Interestingly, particles from hardwood (pear wood and bamboo) and softwood (cypress and pine wood) combustion were mainly soot and OM in the flaming phase, respectively. The combustion of foam boxes, rubber tires, and plastic bottles/bags in the flaming phase released large amounts of soot internally mixed with a small amount of OM, whereas the combustion of printed circuit boards and copper-core cables emitted large amounts of OM with Br-rich inclusions. In addition, the printed circuit board combustion released toxic metals containing Pb, Zn, Sn, and Sb. The results are important to document properties of primary particles from combustion sources, which can be used to trace the sources of ambient particles and to know their potential impacts in human health and radiative forcing in the air.

Genotoxic and inflammatory effects of organic extracts from traffic-related particulate matter in human lung epithelial A549 cells: the role of quinones.

Traffic-related particulate matter (PM) is associated with adverse health effects. Quinones present in the traffic-related PM are hypothesized to contribute to these harmful effects through reactive oxygen species (ROS) generation. However, the impacts of the traffic-related PM and quinones on inflammatory processes and genotoxic damages are less well known. In present study we aimed to examine the genotoxic and inflammatory impacts of organic extracts from traffic-related PM (oTRP) in human lung epithelial A549 cells, and reveal the contributions from quinones. Significant cytotoxicity and DNA damage were caused by oTRP. The pro-inflammatory genes, interleukin-6 (Il-6), interleukin-8 (Il-8) and tumor necrosis factor (Tnf), and two aromatic hydrocarbon receptor-regulated genes, Cyp1a1 and 1b1, were significantly up-regulated by oTRP. A concomitant increase in ROS was observed, suggesting that oTRP may mediate genotoxic and inflammatory effects through oxidative stress pathway. Second, the effects from two typical airborne quinones, 9,10-anthraquinone (AQ) and 1,4-naphthroquinone (NQ) were compared. NQ, but not AQ, induced significant DNA damage in A549 cells. NQ up-regulated Il-8, Tnf, and Mcp-1 genes, while AQ induced the expression of Rantes gene. These results suggest that the NQ and AQ may participate in the pro-inflammatory responses through releasing different types of cytokines/chemokines.