[Establishment and Application of Foshan Ozone Concentration Forecast Equation]

The formation and changes of ozone (O₃), a secondary pollutant in the atmosphere, are complex, and ozone forecasting has become one of the current problems in air pollution prevention and control. In this study, the relationships between the near-surface O₃ concentration and meteorological elements (high- and low-level) in Foshan from 2014 to 2017 were analyzed, and the concentration forecasting equation was established, tested, and applied. The results showed that the near-surface O₃ changed closely related to high- and low-level meteorological elements. Meteorological elements such as temperature and sunshine hours were significantly positively correlated with O₃ concentration, whereas relative humidity, total (low) cloud cover, and wind speed were negatively correlated with O₃. Heavy O₃ pollution often occurred with meteorological conditions of low wind speed, sunny days and few clouds, low relative humidity, longer sunshine time, and higher temperature. The definitions of high-concentration O₃ potential index (HOPI) and wind direction index (WDI) in the Foshan area could better characterize the meteorological conditions of O₃ pollution. Considering 13 meteorological elements, such as HOPI and WDI at different heights, the O₃ concentration forecasting equation in the Foshan area was established using multi-indicator stacking and multiple stepwise regression methods. Using the 2018 data, it was found that the correlation coefficient R between the simulated values and the measured values reached 0.82, and the forecast equation had a good fitting effect and predictability.