基于逸度模型的成都市NO₂多介质环境中的分布研究

Research on the Distribution of NO₂ in the Multi-Media Environment of Chengdu Based on the Fugacity Model

摘要: 为了研究成都市NO₂在多介质环境中的分布规律，本文运用Mackay的III级逸度模型，以质量守恒定律为基础，依据研究区域的多介质环境(大气、水体、土壤、沉积物)特点，选择逸度作为平衡判据，建立本地化逸度模型，研究成都市NO₂在多介质中的环境行为，并通过改变环境温度和降水量研究气象条件的变化对NO₂在各环境相中迁移的影响。结果表明：(1) 在大气、水体、土壤、沉积物这四个环境相中，水体相是NO₂主要的汇，约占总储量的99%，并且NO₂在研究区域内最主要的耗散途径是在水体中损失。NO₂在成都市各环境主相之间的迁移主要是以土壤–水体为主，其次为大气–土壤，两者分别占整体迁移通量的48%和49%；(2) 气象条件(环境温度、降水量)对所在研究区域成都市NO₂多介质环境中的迁移变化存在一定影响。水体–大气，土壤–大气、沉积物–水体以及水体–沉积物相间NO₂的迁移速率随着温度的升高而增大，自1月开始，环境温度逐渐升高，至7月达到最大值26.6℃，NO₂的相间迁移速率也增长到2023年间的最高峰；降水量与水体–大气，土壤–大气、沉积物–水体以及水体–沉积物相间NO₂的迁移速率呈反向变化的关系，当降水量于7月达到最大值265.95 mm时，四个相间NO₂的迁移速率对应为最小值。

Abstract: To investigate the distribution patterns of NO₂ in multimedia environments in Chengdu, this paper employs Mackay’s Level III fugacity model. Based on the law of mass conservation and the characteristics of the multimedia environment (atmosphere, water, soil, and sediment) in the study area, fugacity is selected as the equilibrium criterion to establish a localized fugacity model. This model is used to study the environmental behavior of NO₂ in multimedia environments in Chengdu. Additionally, the impact of meteorological condition changes on the migration of NO₂ in various environmental phases is examined by altering environmental temperature and precipitation levels. The results indicate: (1) Among the four environmental phases (atmosphere, water, soil, and sediment), the aqueous phase serves as the primary sink for NO₂, accounting for approximately 99% of the total inventory. The dominant dissipation pathway of NO₂ in the study area is loss in the aqueous phase. The primary migration routes of NO₂ among the major environmental phases in Chengdu are soil-water (48%) and atmosphere-soil (49%). (2) Meteorological conditions exert a discernible influence on the migration of NO₂ in Chengdu’s multimedia environment. The migration rates of NO₂ across the water-atmosphere, soil-atmosphere, sediment-water, and water-sediment interfaces increase with rising temperature. Since January, the environmental temperature has gradually risen, reaching a maximum of 26.6˚C in July. The inter-phase migration rate of NO₂ has also increased to its peak level during the year 2023. The relationship between precipitation and the migration rates of NO₂ between water - atmosphere, soil - atmosphere, sediment - water, and water - sediment shows an inverse variation. When precipitation peaks at 265.95 mm in July, the migration rates of NO₂ across the four interfaces reach their minimum values.