Respirable particles

Kim CS. Methods of calculating lung delivery and deposition of aerosol particles. Respir Care 2000 45(6) 695-711. 

The quality of manufacture of a particular TCA depends of 14 parameters linked to the raw material itself and one parameter linked to the manufacturer (material of protection if necessary like dustmask, eyeshield, faceshield, full face particle respirator, gloves, respirator cartridge, respirator filter) ... 

HMiS personai protection Safety goggles, particle respirator, gloves, and protective clothing ... 

Particle, respirable (safety) A particle small enough to be inhaled into the lungs of a healthy person, usually smaller than 10 microns. 

Curti PC, Genghini M. Role of surfactant in alveolar defence against inhaled particles. Respiration 1989 55(suppl l) 60-67. 

Exposure limits for siHcon carbide and powders of zirconium compounds (including zirconium dioxide) have been estabHshed by ACGIH. TLV—TWA s are 10 mg/m and 5 mg/m, respectively. OSHA guidelines for zirconium compounds call for a PEL of 5 mg/m. There are no exposure limits for siHcon nitride powder, but pmdent practice suggests a TLV—TWA of 0.1 mg/m. The soHd ceramics present no apparent health hazard. In machining such ceramics, however, care should be taken to prevent inhalation of respirable particles in amounts in excess of estabHshed limits. Disposal should be in approved landfills the materials are inert and should pose no danger to the environment. 

Barium metal and most barium compounds are highly poisonous. A notable exception is barium sulfate which is nontoxic because of its extreme iasolubihty ia water. Barium ion acts as a muscle stimulant and can cause death through ventricular fibrillation of the heart. Therefore, care must be taken to avoid contact with open areas of the skin. Workers must wear respirators (of type approved for toxic airborne particles), goggles, gloves, and protective clothing at all times. The toxic barium aluminate residue obtained from barium production is detoxified by reaction with a solution of ferrous sulfate and converted iato nontoxic barium sulfate. According to OSHA standards, the TWA value for Ba and Ba compounds ia air is 0.5 mg/m. ... 

Because a filter sample includes particles both larger and smaller than those retained in the human respiratory system (see Chapter 7, Section III), other types of samplers are used which allow measurement of the size ranges of particles retained in the respiratory system. Some of these are called dichotomous samplers because they allow separate measurement of the respirable and nonrespirable fractions of the total. Size-selective samplers rely on impactors, miniature cyclones, and other means. The United States has selected the size fraction below an aerodynamic diameter of 10 /xm (PMiq) for compliance with the air quality standard for airborne particulate matter. 

Airborne particles with diameters less than 1 micron, as in the case of asbestos, are potentially respirable therefore, the manufacture of all submicron diameter carbon particles includes a responsibility to ensure that no health hazards arc... 

Approximate Values in Units of Percent The particle size distribution in a total dust sample is unknown and error in the XRD analysis may be greater than for respirable samples. Therefore, for total dust samples, an approximate result is given. (4) Nondetected A sample reported as nondetected indicates that the quantity of quartz (or cristobalite) present in the sample is not greater than the... 

Finer particles ( < 3 pm), termed respirable particles, pass beyond the ex-trathoracic airways and enter the tracheobronchial tree. Impaction plays a significant role near the tracheal jet, but sedimentation predominates as the effects of rapid conduit expansion dampen in the distal trachea and beyond. Sedimentation occurs when gravitational forces exerted on a particle equal drag forces, i.e., when particle velocity falls to u . As mean inspiratory air-stream velocity gradually declines along the tracheobronchial tree, particle momentum diminishes and 0.5-3 pm MMAD particles settle out of the airflow and onto mucosal surfaces. 

Aerosols are also a form of a mist characterized by highly respirable, minute liquid particles. They can be formed by atomizing, spraying, or mixing, or by violent chemical reactions, evolution of gas from a liquid, or escape of a dissolved gas when pressure is released. 

Respirable particles Particulate matter of such a size that it can pass through the body defences and into the lungs, where, depending on its nature, it will either deposit itself or be exhaled. 

Do NOT wash away into sewer. Sweep spilled substance into containers if appropriate, moisten first to prevent dusting. Carefully collect remainder, then remove to safe place. Personal protection P3 filter respirator for toxic particles. Unbreakable packaging put breakable packaging into closed unbreakable container. Do not transport with food and feedstuffs. EU Classification Symbol T, N R 21-25-36/38-48/23/25-50/53 S 1/2-35-36/37/39-45-60-61 Note A, 1 UN Classification UN Hazard Class 6.1 ... 

Tsilibary and Wissig, 1977 Bettendorf, 1979). Abnormal respiration (as a result of anesthesia) affects the retention time of intraperitoneally injected particles. Anesthesia which stimulates respiration results in a decrease of retention time while respirationsuppressing anesthesia results in the opposite effect (Courtice and Simmonds, 1954). 

Particles in the respirable size range, i.e. about 0.5—7 pm, will, once dispersed, remain airborne for extended periods. Indeed since they are sensitive to slight air currents they may be permanently suspended. 

Quartz on filter media in a clay matrix is also available from NIST. The SRM 2679a is certified for quartz at three levels 30.8, 80.2 and 202.7 [xg/filter respectively. Respirable silica in powder form is also issued by NIST SRMs 1878a and 1879a are crystalline silica materials with particles in the respirable range and they are intended for use in X-ray diffraction and infrared spectroscopy. 

---