Determination Of Volatile Organic Compounds And Carbonyl Compounds In Cabin Of Vehicle Under Natural Exposure

With the rapid development of China’s economy, it’s more and more that people’s desire to purchase a car. In recent years, China’s vehicle growth quantity of about 15 million every year, followed by a large number of drivers.. As of 2014, China’s vehicle population Is 264 million, vehicle drivers more than 300 million people; In the 264 million vehicles, there are 154 million for the car, there are more than 246 million people in the car driver. Small passenger car up to 117 million, compared to 2013 increased by nearly 20%, of which more than 90 percent of private cars, the average per 100 households have 25 private cars. With the increase of car ownership, people pay more and more attention to the safety of automotive interior air environment, the air pollution problem has caused wide public concern. Many organizations in our country on the user’s vehicle air quality testing results show that nearly half of the vehicle air quality is not qualified. therefore, the vehicle air quality and transmission quality, safety air bag quality and vehicle tire quality is known as the four major issues of automotive product quality.Although China promulgated the interior VOCs sampling and analysis methods in 2007, but the method of sampling the threshold is relatively low, can not generally represent the actual use of the user conditions. When people use the car, often encounter the situation of high temperature exposure, At this time, due to the increase in the internal temperature of the vehicle, the concentration of VOCs inside the car will be increased by a geometrical factor. Therefore, there may occur a result qualified in accordance with national standards is detected, the test results in the exposure condition will be far exceeded, resulting in affecting human health. Vehicles exposed to outdoor exposure, affected by various factors, so this paper the results of sampling factors affecting exposure conditions made a thorough study and discuss the necessity and feasibility.The main work of this paper is divided into two parts:Firstly, the influence of temperature, humidity and air tight time on the VOC emission rate in the vehicle is discussed. 1. continuous test the exposure car at different temperatures,they were sampled at 25℃,35℃, 45℃,55℃, 60℃. The results show that with the increase of temperature, the concentrations of harmful substances in the car were significantly increased;2 Sampling and analysis of 3 kinds of different vehicles in high humidity and normal humidity conditions, the results showed that the impact of humidity on the concentration of harmful substances has uncertainty;3. Discusses the effect of air inside the closed time of VOC concentration, measured vehicle after five hours of exposure to sunlight, air temperature in the car reach the highest value, car VOC concentration is close to saturation. At the same time, we found in the vehicle for up to 1 years of tracking and monitoring, with the aging of the material in the car, will produce a new harmful components.Secondly, some key factors affecting the sampling results are discussed, which are the factors that affect the adsorption rate of the sampling tube and the influence of Sampling connection pipe on the sampling results. Through the experimental design, we found:1 With the sample flow rate increases, the adsorption rate of Tenax-TA and DNPH will gradually reduce, sampling flow rate control in less than 400 ml / min more appropriate; 2 As the temperature increases, the adsorption rate of Tenax-TA will be gradually reduced, while DNPH adsorption rate will be gradually increased, so when sampling under high temperature conditions, in order to prevent the occurrence of Tenax-TA penetrating effect, should the series two Tenax-TA sampling tube to ensure sampling accuracy; 3. With the increase of humidity, the adsorption rate of Tenax-TA gradually decreased, but the effect was small. When humidity is 85%,the adsorption rate of BTEX was more than 95%, while humidity had no obvious effect on DNPH; 4. When the silicone rubber tube is used as a sampling connecting pipe, the adsorption of benzene is seriously affected, should use Teflon connecting pipe,reduce the use of silicone rubber connecting pipe and reduce the distance between the sampling tube and the Teflon connecting pipe.Through the above experiment set sampling method, can effectively improve the accuracy of detection results in the exposure car.