[Characteristics of Ozone Pollution, Meteorological Impact, and Evaluation of Forecasting Results Based on a Neural Network Model in Beijing-Tianjin-Hebei Region].

The ozone concentration characteristics of 13 cities in Beijing-Tianjin-Hebei regions from 2016 to 2020 were analyzed based on ecological environment monitoring and meteorological observation data. The influence of meteorological elements such as daily maximum temperature (), daily average ground pressure (), daily average ground relative humidity (RH), and daily average ground wind speed () on ozone concentration[(O-8h)] and the exceeding standard rate of O-8h were discussed. The AQI, ozone concentration range, and ozone pollution level forecast accuracy rates were evaluated using the neural network statistical model. The results showed that the concentrations of O-8h-90per[(O-8h-90per)] of 13 cities in the Beijing-Tianjin-Hebei region from 2016 to 2020 were 157.4, 177.2, 177.3, 190.6, and 175.6 μg·m, respectively. The regional ozone concentration increased by 11.6% over the five years from 2016 to 2019. From 2016 to 2019, there was an overall upward trend in volatility, followed by a decline in 2020. Compared with that in 2016, the concentration of O-8h-90per in the other 10 cities increased by 6-45.5 μg·m, except for in Beijing, Zhangjiakou, and Chengde, where it decreased slightly. The average value of (O-8h) from April to September was higher than 100 μg·m, and the highest monthly average concentration of O-8h was 158.10 μg·m in June. The range of the over standard rate of O-8h was 8.6%-19.2% in the 13 cities, and 97.8% of ozone concentrations exceeded the standard in the period from April to September. At the regional scale, the concentration of O-8h had the strongest correlation with the daily maximum temperature. Furthermore, when was in the range of 25-28℃, the concentration of O-8h in the 13 cities began to exceed the standard concentration of 160 μg·m. Additionally, the concentration of O-8h negatively correlated with . When RH was below 60%, ozone concentration increased slowly with relative humidity in most cities. When RH was above 61%-70%, ozone concentration decreased with the increase in daily relative humidity in most cities. When ozone exceeded the standard concentration of 160 μg·m, the dominant wind was mainly southerly wind, and the high ozone concentration in most cities tended to be concentrated in the low wind speed range of 2-3 m·s and below. Moreover, the correlation coefficient range of the statistical model of OPAQ 1-9 days in advance was 0.72-0.86, the average accuracy of AQI level forecasts was 67%-86%, and the average accuracy of O-8h concentration forecasts was 63%-84%. In April to September, when ozone exceeded the standard of 160 μg·m, the accuracy rates of the model forecast of light ozone pollution and ozone exceeding the standard concentration of 160 μg·mthree days in advance were 69% and 66%, which can provide a reference for the management and control of ozone pollution.