Document gO8K78dyOx0dBmD5X1JbxDOQ

FILE NAME: Pennsylvania (PA) DATE: 1967 DOC#: PA031 DOCUMENT DESCRIPTION: Occupational Health Bulletin - Exposure to Mineral Dusts 01/13/1994 02:34 7168430708 LIPSITZ AND PONTERIO PAGE 05 Exposure to duau in lho air ol many work places eoaciltuios e potential fcrasxd to health. Grindint crushing, biasting and drilling produca dust particles ranging in size tram the sub-nucro*copie to the visible. Inhalation al dual m ay insult in a variety Ol lung diseases known ca Ihe pneumoconioses. In common usage. (h!s word has become a general term for any at the dost diseases oi the lung. Roro we are concerned only with pneumoconioses j?roducid"5y mineral dusts- The lung dicocnea a t a ri1below a re th ere to n j to this r irm: ot nuata. i-neae Inclu5a Cool works* pneumoconioses r ^A cbeatoaia ~~ -> / Slimnnti. Haritosis Tleoste Siderosis FACTORS AFFEC IN o ' DEGREE O P HAZARD The degree of hazard associated with exposure to a particular dust depends o n : (I) site oi dust panicle 2) physical and chemical composition oi the dust (3) concentration and duration ol exposure. Size.of Dust Particle Funomzialy tor m m . healthy lungs can deed with a certain quantity of dust without being damaged. O nly extremely minute isliclee reach the lungs and art retained in them Few particles g ra d e r Ikas 5 microns reach the. deep long regions, Usually these particles are in the range oi 0.3 to 2 microns, a micron being millimetre in diameter. Most p a rticles larger than 5 microns either settle out ol the air before it is. breathed, or are trapped in the m ere linns el the nose and root and are expelled or swallowed. Extremely fine particles, below 3 microns, are trapped in (ho trachea (windpipe) and bronchial tree, including the deeper portions at the lungs. Reference to the drawing shows that Camparison ol this system io a tree is an apt one. lust a s the trunk oi a tree has branches of different sizes, tho respiratory trunk (trachea) has two branches or tubes -- the broschl which, after further divisions, divide a is. i Sesie < h m n ( respiravary ehannels of human temp. Ksprvuce from tils Brilith Journal of Industrial Medicis. Jfifff, sot. . V. 24S. into sm aller tu b e s----the bronchioles. The latter lo ad to iha a ir sacs in the lower lung (alveoli), the a ro s of the lungs in which oxygen p a u s e into tho blood Etmani Fardeles deposited in the d e ep lung creas ore r -oc *d by a moving blanket oi mucous. This DUCOUt cotto the air passages and auurtantiy m erres (he porteles is an upwards direction towards tho th ro at Movement of this mucous blanket In coded by millions oi hsdr-liko processes, or cilia, found a n the surface of the eolia lining, the bronchi, or e poaeegea. Pesddos m ay a b e be expoliad by coughing and sc edng or bo engulfed and r s mv/r od b y *osvenger cells or phagocytes. It ia only when these defences ora dam aged or overwhelmed b y -U g h canetmBXrtiocs B id re p ea te d exposure to harmful s b e ten o s ha o ra environm ent Ihet G an g es from the normal occur. B00008047 i