A preliminary assessment of BTX pollution in urban air in the city of Lanzhou

A multi-pollutant assessment of Benzene, Toluene and Xylene was performed in the Chinese urban environment of Lanzhou city by means of diffusive samplers. The focus was upon an assessment of the interrelationships between different pollutants and different types of sampling sites. The considerable number of samples taken with the technique proposed in this work allows for the statistical treatment of data along the space coordinates. That is very useful in air quality management and control, due to the possibility to infer the statistical distribution of data and compare its parameters with reference values, such as mean, limit or standard values, etc. It was found that distributions of BTX are successfully estimated from a statistical point of view from the Normal distribution. Therefore, it was demonstrated that the passive sampling method can be used in a large-scale project for the measurements of BTX spatial variability at extremely low cost. Errors found in measurement technique are extremely small and valuable for the purposes of this work. Moreover, many of the measurement sites in this study could not be operated using conventional methods due to the difficulties in transportation, power supply, location, etc. Thus this technique allows to map big areas difficult to be reached with heavy or large instrumentation.