Temporal Changes Trend in External-Origin Dust in Arid Cities of Iran

Introduction: Dust storms in arid regions lead to air pollution that jeopardizes human health and the environment. Monitoring the temporal and spatial variations of these events is crucial for mitigating their risks. Materials and Methods: This study analyzed dust events in Iran, classifying them as internal (coded 07, 30-35, 98) and external (coded 06). The frequency of each dust type was calculated for every city, and the proportion of internal and external dust events was determined. Then, the contributions of both internal and external dust sources were examined in Iranian arid cities. Finally, using Mann-Kendall test, the study analyzed changes in external-origin dust in these cities. Results: Over 58% of recorded dust events originated from external sources. Significant increases in external dust frequency were found in most months for Tabas, Kashan, and Bandar Abbas (|Z statistic| > 1.96), while significant decreases were observed in Bam, Zahedan, and Iranshahr ((|Z statistic| > 1.96). A seasonal increase in external dust was prevalent in 72%, 7%, 58.6%, and 62.1% of Iranian cities during winter, spring, summer, and autumn, respectively. Annually, 75.9% of the cities experienced rising levels of external dust, while 17.2% faced decreasing trends. Conclusion: The results can be used as an efficient tool to improve management policies and programs in order to reduce the negative effects of dust on the environment and community health in dusty urban areas.