its chemical and mineral composition varies depending on where it comes from these variations have a bearing on its health impact the size of dust particles is key and assessing their impact on health the kuwaiti scientists measure the size range by looking at the light scattered when a laser beam is shown through the sample. the size of the particle is very important and causing a disparity problems. eighty five percent of dust size in kuwait is ten micro meters and that's the size that usually cause respiratory complaint and exacerbation of us. when we breathe in dust particles smaller than ten micro meters the pm ten particles become lodged in the lungs causing breathing difficulties even smaller particles pm two point five can actually cross directly into our bloodstream. these small particles they interfere with the gas exchange.