Document Type : Research Paper
Instrumentation Division, Brookhaven National Laboratory, Upton, NY, USA.
Interdisciplinary Science Department, Brookhaven National Laboratory, Upton, NY, USA.
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA.
Biomass-burning boilers and stoves are widely used in many parts of the world, producing combustion emissions linked with health risks. Combustion emission nanoparticles (NPs) were collected from four representative wood burning boilers using oak cordwood at specific times in the burn cycle. The morphology and composition of the NPs was characterized using transmission electron microscopy and energy dispersive X-ray analysis. To determine the degree of NP cytotoxicity with human lung tissue, the combustion NPs were introduced to incubated lung bronchial epithelial monolayers (NCI-H292) in vitro at doses of 0.1 × 10-6 and 3.0 × 10-6 kg/L for 2 and 4 h. Histochemical analysis showed that cell death increased by a factor of 3.5 for both doses after 4 h when compared to the control. Ultrapure NPs prepared by wet chemical methods were also introduced to the epithelial lung cells for similar doses and exposure times and the cultures exhibited significantly reduced mortality. Electron microscopy was used to study the mechanism of cell mortality for the synthesized and combustion-based NPs by examining how the NP byproducts interacted with individual cell organelles. It was found that cell survival was strongly correlated with the absence of contaminants (salts, heavy metals, poly aromatic hydrocarbons) associated with the NPs entering the cells. Synthesized NPs consisting of pure carbon were relatively well tolerated and could be excreted without damaging the cell ultrastructure. Thus, careful removal of extraneous contaminants by controlling the burn cycle with a catalyst is essential to minimize the health and environmental effects of wood biofuel combustion. In better words, optimized advanced technology wood-burning boilers and stoves can provide a CO2-neutral energy source and significantly contribute to a future where fossil fuels have a reduced role.
- The morphology of combustion-emitted and lab-synthesized nanoparticles (NPs) was compared with electron microscopy.
- The composition of combustion NPs from conventional and advanced wood boilers was determined by energy dispersive X-ray analysis.
- Cell toxicity from combustion NPs (0.1 to 3.0×10-6 kg/L aqueous solutions) was determined with optical histochemistry.
- Cytotoxicity in human lung cells was 3.5 times greater for combustion emitted NPs compared to pure graphene-based NPs.
- The mechanism of ultrastructural damage from cell-ingested NPs was studied with electron microscopy.