Gravity-current-driven transport of haze from the North China Plain to Northeast China in Winter 2010-Part 2: Model simulation with tagged tracers

Abstract

In this study, the Nested Air Quality Prediction Model System (NAQPMS) with an online air pollutant tagged module was employed to investigate the contribution of regional transport from the North China Plain (NCP) to Northeast (NE) China during a severe haze episode in the winter of 2010. For simulating particulate matter with a diameter of less than 10 μm (PM10), the NAQPMS model was in good overall agreement with observations in NCP and NE China. Using the tagged module, contributions from regional transport and local sources to the ground PM10 concentration at four representative sites, namely Yingkou, Liaoyang, Tieling, and Jilin, along the haze transport pathway in NE were estimated. The results showed that the regional contribution from the Beijing-Tianjin-Hebei area and Shandong Province accounted for 33-87% of the PM10 pollution on average at the above four sites, with the contribution decreasing along the pathway from NCP to NE. The impact of regional transport on the peak PM10 concentrations at the four sites was also investigated. The contribution of the Beijing-Tianjin-Hebei area to PM10 pollution was 73% at the nearest site Yingkou and 30% at the farthest site Jilin, which is approximately 1500 km from Beijing. Our results demonstrate that Beijing-Tianjin-Hebei may significantly contribute to haze pollution in NE, particularly under favorable meteorological conditions. Thus, efforts to improve the air quality in NE China need to focus on controlling both local and regional emissions, particularly from the downwind NCP.