With seemingly more regularity in March and April, dust from massive storms in Mongolia and northern China (primarily the Gobi Desert region) ends up infusing our airshed with a fine, homogeneous haze. The effects started to be apparent last week, but intensified over the weekend. The Gobi Desert storms started on March 11, 2014, according to this article at NASA’s MODIS website: MODIS 2014-03-23 and were still visible from satellite imagery on April 3, 2014: MODIS 2014-04-16. Studies on the phenomenon of the long-range transport of Asian dust have been published. Here are two examples: VanCuren-jan04 and Szykman, Mintz, Creilson & Wayland 2003.