Nitrate pollution deterioration in winter driven by surface ozone increase
Zekun Zhang, Bingqing Lu, Chao Liu, Xue Meng, Jiakui Jiang, Hartmut Herrmann, Jianmin Chen, Xiang Li
Abstract
Abstract Recently, nitrate (NO 3 – ) levels in winter pollution in eastern China have been increasing yearly and have become the main component of PM 2.5 . The factors contributing to this rise in surface NO 3 – concentrations remain unclear, complicating the development of targeted pollution control measures. This study utilizes observational data from Shanghai during the winter 2019, alongside box model simulations, to recreate the NO 3 − pollution event and identify the key factors in the growth process. The analysis demonstrated that a rise in winter ozone levels significantly promotes NO 3 – production by facilitating NO x conversion via gas-phase and heterogeneous reactions. These findings could explain the correlation between the synchronous increase of surface ozone and NO 3 − in recent years. Furthermore, simulation of control strategies for NO x and volatile organic compounds (VOCs) identified an approach centered on ozone reduction as notably effective in mitigating winter NO 3 – pollution in the Yangtze River Delta.