{"pm2_5":{"xgboost":0.30},"pm10":{"xgboost":0.35},"no2":{"xgboost":0.07},"so2":{"xgboost":-0.05},"co":{"xgboost":0.06},"o3":{"xgboost":0.13},"nh3":{"xgboost":0.06}}