From history class and Steinbeck's Grapes of Wrath, I've read about dust storms such as the Dust Bowl of the 1930's that plagued the US during the time of the Great Depression. I've also learned about dust storms in an Air Quality Management course I took in graduate school a couple of years ago. It's a legitimate source of pollution.
In the sandy dunes of the Middle East, a dust storm shouldn't be too surprising. With no cover to ground the topsoil or sand, strong gusts of wind can pick up loose particles and greatly reduce visibility. The problem, though, isn't necessarily the inability to see past two miles ahead of you.
Rather, small particulate matter such as sand can lodge into your lungs and make breathing difficult for those with forms of asthma. This fine matter triggers an automatic "fight or flight" response from your Central Nervous System, quickening your heartbeat and spiking blood pressure as well. If the particulates lodge deep into your lungs, inflammation will kick in 24 hours after exposure, stiffening blood vessels, leaving them impaired for several days. For someone with underlying hypertension or coronary disease, effects of exposure may trigger a heart attack and contribute to heart disease and stroke. (I'm including a powerpoint presentation I actually had to give on fine particle pollution topic, based on a Time article last spring).
But not to worry! Short-term exposure should not leave long-term effects, and the best suggestion would be to cut any strenuous outdoor physical activity for the day and to remain indoors as much as possible, especially pregnant woman or those with the aforementioned lung/heart problems. Israel's Environmental Protection Ministry is also advising schools to keep children indoors for the remainder of the day.
The sand storm is expected to pass by tomorrow morning and will hopefully clear the air by Sunday night, erev Rosh Hashana, when I'll be heading to Jerusalem. But, more on that later. For now, I will be staying inside for Ulpan and keeping my lungs clean :)