Air pollution from automobiles, in the form of nitrogen oxides (NOx) and volatile organic compounds (VOCs) are increasing continuously due to the rapid development of transportation activities, which can cause a number of environmental and social issues and impact public health. Nano titanium dioxide (TiO2) has been found to have photocatalytic properties, which, under UV light can oxidize and remove VOCs and NOx from the atmosphere. Although TiO2 treated paving materials have great potential to improve air quality, current techniques to adhere TiO2 to substrate materials are either not durable or reduce direct contact of TiO2 with UV light, reducing the photocatalytic effect. To solve this technical difficulty, this study innovatively introduces atmospheric pressure cold plasma (APCP) techniques to transportation engineering to coat TiO2 to pavement. The objective of this study is to test the concept of using APCP techniques to create a durable TiO2 coating on the surface of paving materials to reduce NOx and VOCs at the street level. An APCP generator was developed to produce activated radicals from precursor molecules using high voltage streamers as the plasma source, and to immobilize nano TiO2 powder to substrate pavement materials. Preliminary results are promising, showing that TiO2 can be incorporated successfully into an APCP environment. Evidence of TiO2 has been identified based on field emission scanning electron microscope (FE SEM) images. The TiO2 coated material with APCP shows some ability to reduce nitrogen oxides when exposed to UV light in an environmental chamber. However, such effect is limited which is hypothesized due to either limited deposition rate of the plasma polymerized film or the plasma polymerized film blocking the direct contact of TiO2 with the UV light. Further research is therefore recommended to optimize the APCP generator for improved efficiency. Also a more in depth study should be conducted on the plasma polymerized film and its interaction with the TiO2
