The UN's weather and climate agency said the episodes affected public health and the environment, and disrupted economic activity.The World Meteorological Organization said that every year, around 2,000 million tonnes of dust enters the atmosphere, and can travel for thousands of kilometres across continents and oceans.The main dust sources are major deserts such as the Sahara in Africa, the Gobi in Asia, and the Arabian Desert in the Middle East.Though it is a natural process, poor water and land management, drought and environmental degradation "are increasingly to blame", the WMO said."Sand and dust storms affect air quality and human health," WMO chief Celeste Saulo said in a statement."They reduce agricultural productivity, disrupt transport and aviation, strain water and energy systems, and damage ecosystems. No country is immune to their impacts."In its 10th annual Airborne Dust Bulletin, the WMO said that globally, overall average dust concentrations last year were 12.1 microgrammes per cubic metre of air -- slightly down on the 12.5 recorded in 2024 -- though with big regional variations.The highest annual mean dust concentrations worldwide were again in the Bodele Depression in Chad, one of the planet's most active dust source regions, at around 800 to 1,100 microgrammes.Texas takes a hitThe desert border region of Mexico and the United States saw exceptionally frequent, intense and prolonged dust storms in 2025.The number of dust storms, 12, was the highest since 1935, when the United States was in the midst of its "Dust Bowl" disaster, the WMO said.El Paso in Texas experienced 50 days with dust weather -- more than double the annual average.