A Gaussian-box modeling approach for urban air quality management in a northern Chinese city - I. model development

A Gaussian-box modeling approach was presented in this paper to examine the urban air quality due to multiple point- and area-source emissions in the northern Chinese city of Fengnan, which is associated with a deteriorated air quality as a consequence of industrialization and rapid urban growth. A 3-D multi-box (3DMB) air quality model was developed to predict air quality due to area-source emissions. It improved upon the conventional box models by allowing consideration of more details in spatial variations of emission sources and meteorological conditions. The modeling domain was divided into various layers within the mixing height, while each layer was associated with a number of sub-boxes. A multi-source and multi-grid Gaussian modeling approach was then applied to predict the air quality in different sub-boxes that are associated with multiple point-source emissions. Thus the Gaussian-box modeling approach could effectively simulate impacts of both area- and point-source emissions but also reflect more details of the spatial variations in source distributions and meteorological conditions. This modeling approach was employed to predict daily average SO2, TSP and PM10 concentrations for each sub-box during the heating and non-heating seasons, respectively. The analysis of the mean normalized error of the modeling results demonstrates the feasibility and applicability of the developed method, and the presented method could provide more useful and scientific bases for developing effective urban air quality control and management strategies.