The emission factors for indoor straw combustion are a major data gap for estimating the polycyclic aromatic hydrocarbon (PAH) emissions in China. The emission factors for open-fire straw burning were borrowed from our previous study and a rough estimate was developed. As one of the most important emission sources in China, the emission factors for indoor straw combustion needed to be determined and revised accurately. In this study, a representative straw in rural China was collected and burned in similar conditions with those used by countryside families. The smoke produced was sampled and the PAH concentrations were analyzed by gas chromatography-mass selective detection (GC-MSD), and much higher emission factors were found. Based on the newly measured emission factors, the emission amount from indoor straw combustion was updated. In addition, recently published emission factors were compiled in a comprehensive database and some new sources were included. Additionally, the emission inventory was extended to cover the period from 1950 to 2005 and upgraded to a scale resolution of one kilometer. In the updated inventory, the total quantity of 16 PAHs emitted from China was 116,000 tons in 2003, with indoor straw and firewood combustions as the most important sources. Although vehicular emission contributed a relatively small percentage of the total emission, it was still one of the major sources in the urban areas of China. The total PAH emission increased continuously for four decades, starting from 1950, but fluctuated since 1990 due to variations in coke production.

No abstract

Aluminium oxide (Al 2 O 3 ) and titanium dioxide (TiO 2 ) nanoparticles (NPs) have been widely used in nanotechnology-based products. Recently, researchers and the public have raised concerns about the adverse effects of these NPs in biological systems, particularly in humans. The aim of this study was to investigate the possible adverse effects of these two common metal oxide NPs on human lung epithelium cells (A549) and to investigate NP size-dependent effects on these cells, considering both the primary and hydrodynamic particle size. NPs were found to inhibit cell viability and proliferation at the highest concentration level (10 mg/mL) included in this study, as measured by a clonogenic assay. Moreover, cell viability, proliferation and metabolism were impaired to a greater extent by the smaller NPs (5 nm TiO 2 and 10 nm Al 2 O 3 ) relative to the larger particles (200 nm TiO 2 and 50 nm Al 2 O 3 ) included in this study, as measured by cell proliferation and metabolism. Notably, the observed cytotoxic effects correlated to the primary size, rather than the hydrodynamic size. Similarly, NP cytotoxicity was found to be correlated with the NP surface area. These findings highlight the importance of including primary size and surface area information in NP characterisation in cytotoxicity studies.

No abstract

No abstract