One study use a modified ALI exposure system developed by Hsiao et al with combustion products from the combustion systems for cell toxicity testing. We evaluated the feasibility of the ALI exposure system using for air mixtures from combustion.

The incense was placed in burning system and high voltage power supply was applied on the exposure system. To increase particles deposition on Transwell. Scanning Mobility Particle Sizer was used to measure the particles levels in the exposure system. There levels of combustion products were introduced to cell exposure chamber. Filtration system was then used to remove the particles from the system, to create a gas phase exposure scenario for ALI. Trypan blue staining and MTT assay were used to measure the cell viability, and ROS production was used to evaluate the oxidative stress from combustion products.

One results shown the range of particle diameter were 100 to 400 nm with unimodal distribution. The number median diameter were between 163nm to 195nm three levels of generation source. The deposition rate of the exposure system shows the increased 5% to 15% with applying voltage.

Cell viability reduction rate shown a significant decrease with increasing exposing doses in a linear relationship (R2 = 0.9501). The increase of ROS release also shown a significant linear relationship with exposing doses (R2 = 0.9071). Linear dose dependent effects also shown on gas phase exposure. However, the toxicity were lower than mixtures of combustion.

One study use significantly, decrease linear dose-dependent effects deposition rate and exposure time to estimate the exposure dose for cells both could be observed on reduction rate of cell viability and the increase of ROS for mixture of combustion and only gas phase. One system can effectively use to different combustion products, showing the overall deposition rate on ALI cells should further examine by electron microscopy in the near future.