Abstract
Nitrogen dioxide (NO2) in indoor air is generated from heating appliances, gas ranges, and cigarette smoke. These substances are proven causative substances for respiratory diseases; and as preventive measures in Japan, atmospheric environmental standard and school environmental hygiene standard have been set.
In Japan, Saltzman method or chemiluminescence method is adopted as a standard measurement method for NO2 in the air. Among these methods, the Saltzman method is inconvenient to handle with a wet method using absorbing solution for trapping NO2. On the other hand, the chemilumines-cence method has a large and expensive apparatus. In this study, in order to improve these point, the following measurement method was developed. This method is an NO2 measurement method by HPLC using a 1-hydrazinophthalazine (1-HP) reagent, a mixed scavenger of triethanolamine (TEA) and sodium hydroxide as a scavenger. In this method, an active sampler filled with a scavenger in a glass tube was prepared and basic investigation such as collection efficiency, extraction method, repeatability, comparison between theoretical value and analytical value etc. was carried out. As a result, the collection efficiency for NO2 was 99% and above for one of the collection tubes, the repeatability was 4.1% or less in terms of the relative standard deviation, and the lower limit of determination (0.3 L/min x 30 min) was less than 0.01 ppm. Moreover, a significant correlation was found between the proposed method and Saltzman method, which is a standard test method for NO2. From the above viewpoint, the practicality of this method became clear.
