The September 2022 thunderstorm asthma outbreak in Yulin, Northwest China: A 7-year retrospective analysis (2018–2024)

Objective This study documented a thunderstorm asthma outbreak that occurred on 9–11 September 2022 in Yulin, Northwest China, and conducted a retrospective analysis of epidemiological patterns from 2018 to 2024. Methods A retrospective observational design was employed. Patient data were obtained from Yulin Hospital, The First Affiliated Hospital of Xi’an Jiaotong University. Case numbers were retrieved from the Hospital Information System, and detailed clinical records of hospitalized patients were sourced from the medical records database. Results From 2018 to 2024, the annual incidence of allergic respiratory diseases increased substantially, from 4778 to 26,459 cases. During the thunderstorm period in September 2022, emergency visits surged to 2185 cases, significantly exceeding baseline levels of previous years. Monthly data for 2022 showed a distinct peak in September, with 5647 visits. Pollen monitoring revealed a bimodal distribution, with concentrations sharply rising to 1488 grains/1000 mm 2 on 8 September. Among 93 hospitalized patients, 58.0% had no prior asthma diagnosis, 70.9% had allergic rhinitis, and 59.1% were sensitized to mugwort pollen. Conclusion These findings confirmed thunderstorm asthma as a significant public health threat in Northwest China, driven by the convergence of mugwort pollen exposure and thunderstorm conditions, highlighting the urgent need for integrated early-warning systems in susceptible regions.