./He2018ACP_data, ./YWang2019JGR_data, and ./Song2020STE_data contain the observations of D17O(NO3-), various chemical species, and metereological variables. The details are described in the main text. Contacts for the corresponding authors of these observational papers: 
    
    ZhouQing Xie zqxie@ustc.edu.cn for He+ (2018), ACP
    Xue-Yan Liu liuxueyan@tju.edu.cn, for Y.Wang+(2019), JGR and Song+(2020), STE

Data in ./Compiled_Beijing_AQ-station_data are retrieved from https://quotsoft.net/air (last accessed on 26 January 2021). 

The IPython notebooks (.ipynb files) illustrate how to access the data and reproduce the key figures presented in the manuscript. They are built using Python package "Jupyter". More detailed comments be found inside the notebook files. 

For the code to reproduce the simulations, please refer to model-modification.readme in ./model_modification folder. 

For more details/information, please contact Yuk Chun Chan. At the time of manuscript submission, the email address of Y.C.C is ycchan@uw.edu.