区域间大气污染物相互影响研究的新方法探讨

New method for investigating regional interactions of air pollutants

以气象模型输出的气象场和空气质量模型输出的污染物浓度场为基础,建立了"四维通量法",该方法采用微元法求解大气污染物的输送通量,首次提出了"闭合绘线法"来解决输送过程中最关键的方向问题. 四维通量法在时空维度上都可以进行伸缩,具有普遍适用性. 将该方法应用于研究广州周边地区 PM10和 O3对广州空气质量的影响,并与已有的工作进行对比分析,结果发现: 1、4、7、10 月份输进广州市的 PM10最大值分别是来自东面的 6. 9 t.h -1、南面的 5. 6 t.h -1、南面的 10. 6 t.h -1和北面的 7. 7 t.h -1; 1、4、7、10 月份输进广州市的 O3最大值分别是来自北面的 166.6 t.h -1、南面的 64. 1 t.h -1、南面的 105.6 t.h -1和东面的 256. 2 t.h -1; 在计算简化边界的情况下,四维通量法的计算结果无论从量级上还是从数值上都与前人的研究成果接近,可以预见在计算真实边界的情况下,四维通量法的计算结果将更加精确.

We devloped a ＂ Four-dimensional Flux Model （FDFM）＂ to estimate the transport of air pollutants fluxes with the Infinitesimal Dividing Method, which is based on the meteorological fields calculated from meteorological models and on the concentration field of pollutants obtained from air quality models. For the first time, this method introduces the ＂Closed Painting Line Method＂ to solve the wind direction problem, critical for regional air pollutant transport. The FDFM can be easily adapted and applied, due to its flexibility in changing temporal or spatial dimension. We used FDFM to investigate impacts of PM10 and 03 in adjacent areas on air quality in Guangzhou, and compared our results with previous studies. Our results showed that： （1） the maximum fluxes of PM^0 transported into Guangzhou are 6.9 tons/hours from east in January, 5.6 tons/hours from south in April, 10.6 tons/hours from south in July, and 7.7 tons/hours from north in October; and （2） the maximum 03 fluxes transported into Guangzhou are 166.6 tons/ hours from north in January, 64.1 tons/hours from south in April, 105.6 tons/hours from south in July, and 256.2 tons/hours from east in October. With simplified boundary conditions, the magnitude and values of those fluxes calculated by FDFM are very close to those reported by previous studies. Therefore, the FDFM is expected to produce more accurate results when realistic boundary conditions are employed.