Work Environment and Ergonomics

Dust in the workplace Lucie Kocůrková Content 1. Introduction 2. Core definitions 3. Legal framework 4. Factor characterization 5. Entry, deposition and effects on the human organism 6. Occupational diseases 7. Health risk assessment 8. Prevention 9. Conclusion 2 Learning outcomes •Characterize the risk factor (RF) DUST •Discuss the effects of the RF on the human organism •Characterize related occupational diseases •Define methods of measurement (objectification) of the factor •Assess health risks •Propose and advocate preventive measures Evaluation Synthesis Analysis Application Comprehension Knowledge 3 1. Introduction A significant factor of (non)professional exposure 5 Obsah obrázku text Popis byl vytvořen automaticky Obsah obrázku text, sníh, exteriér, příroda Popis byl vytvořen automaticky Raising importance 6 (ILO, 2021) 2. Core definitions Overview of core terms •Aerosol – dust, fume, smoke, fiber … •Fraction –inhalable, thoracic, respirable, total •Occupational exposure limit (OEL) – Permissible Exposure Limit (PEL) •Inhalation exposure –breathing zone, size-selective sampling, gravimetric technique, real-time sampling (monitoring) •Occupational (Work-related) diseases –Asthma bronchiale, Pneumokoniosis, Silicosis, Asbestosis, Mesothelioma 8 … will be explained one by one during the lecture 3. Legal Framework Workplace hazards http://ehqsconsulting.com/wp-content/uploads/2015/04/OccupationalSafetyHazards-flow-chart.png 16 Dust Included in Chemical Factors (Agents) 17 (98/24/EC) (OHTA, 2019) Included OR not? … in Czech legislation 18 Chemical factors are divided into: •substances and mixtures in general, •lead, •dust, •carcinogens, •mutagens, •substances toxic to reproduction and •Asbestos HEAD III: Conditions of health protection while working with chemical factors and dust Division 1 - General procedures and protection against excessive exposition (Sections 9 - 12) Division 2 - Lead (Sections 13 - 15) Division 3 - Chemical carcinogens, mutagens, elements toxic for reproduction and chemical processes with risk of chemical carcinogenicity (Sections 16 - 18) Division 4 - Asbestos (Sections 19 - 21) (Gov Reg 361/2007 Coll. - §2, par. 1) Risk factors in Czech legislation •Decree 432/2003 Coll. defines work categorization criteria for 13 RFs: 1. Dust 2. Chemical substances and mixtures 3. Noise 4. Vibration 5. Non-ionizing radiation 6. Physical load 7. Body posture 8. Heat stress 9. Cold stress 10. Mental load 11. Visual load 12. Biological agents 13. Increased air pressure 19 Dust in Occupational hygiene •Dust is a polydisperse solid aerosol that is created by human activity during the mechanical processing of solid materials (extraction of raw materials, cutting, grinding, drilling), during comminution processes (grinding, crushing), but also without intervention, e.g. by dispersing particles from an untreated earth's surface due to currents air, volcanic activity, aerosol formation on the sea coast. •The size of dust particles is 1 to 100 µm, particles larger than 30 µm are referred to as coarse dust and they sediment quickly in the environment under normal conditions. •During thermal processes (combustion of organic substances) smoke with particles of 0.01 to 0.5 µm is produced, during chemical oxidation processes (welding) fume with particles of 0.1 to 1 µm is released. •In hygienic practice, the term dust refers to all solid aerosols. 20 Asbestos •Collective designation of various fibrous silicates, the common feature of which is fiber spinability, heat resistance and relative chemical stability. •In nature, they are found in two main groups: amphibole (more dangerous to health), serpentine. •A typical characteristic of asbestos is the formation of a long thin fibrous structure, the fibers tend to split along their length. •Asbestos was previously massively used as a refractory material (its non-flammability and significant heat resistance were used in the production of protective fire-resistant firefighting equipment and in the construction industry). •Proven group 1 human carcinogen (IARC) → use of asbestos prohibited. 21 Tato fotka od autora Neznámý autor s licencí CC BY-ND Aerosol •A dispersion system with a gaseous dispersion medium and a solid or liquid dispersion component. •Suspension of fine solid particles or liquid droplets in air or another gas. 22 Classification of Aerosols (1) According to the origin of the particles: •Natural aerosols: clouds and fogs, atmospheric dust, plant pollen, bacterial and fungal spores (Bioaerosol) •Anthropogenic aerosols: •Aerosols intentionally prepared (e.g. during gasification of solid or liquid fuels or during the application of paints and varnishes, spraying of insecticides, fungicides and herbicides in agriculture, in medicine, etc.) •Undesirable (accompanying) phenomenon of technological / work operations (welding, cutting, grinding, etc.) 23 Classification of Aerosols (2) According to the state of dispersion component: •Mists with a liquid dispersion component •Fumes and dusts with a solid dispersion component •Smogs and smokes that contain both solids and liquids 24 Tato fotka od autora Neznámý autor s licencí CC BY Tato fotka od autora Neznámý autor s licencí CC BY Classification of Aerosols (3) According to the mechanism of formation: Dispersion methods: •Mechanical comminution (crushing, grinding, etc.) and subsequent scattering of dispersion particles in the gas stream (e.g. coal, lime, cement, flour, sugar) •Liquid spraying •Metal sputtering in an electric arc or high-frequency discharge (e.g. oxide fumes) •Fireworks explosion 25 32 33 Deposition of particles in the respiratory system 34 Self-cleaning system ▪Self-cleaning of the lungs (clearance) from solid particles has two components: ▪In the upper respiratory tract, it resides in the mucus coating of the mucous membrane and is transported by ciliated movement. ▪The alveolar component depends both on a mobile covering film and on phagocytosis. ▪These physiological mechanisms transport up to 90% of inhaled dust to the pharynx. ▪Self-cleaning can fail due to excessive dusting (over-exposure) or damage to the self-cleaning processes. ▪„Dust depot“ is created when the alveolar membranes react to dust particles that have not been removed by physiological mechanisms. 35 ▪High concentrations of dust in the air cause dust particles to settle in the eyes, nose and mouth and the associated discomfort.Long-termexposureto theseconcentrations,evenfordustwithoutspecificeffects(sometimescalled"inert"), overloads theself-cleaningmechanisms of thelungs, reducestheoverall defensecapacityof aperson andcancontribute to thedevelopmentof chronicbronchitis.In addition,themechanicalactionof theseparticlesandtheirremovalcancause injuryto theskinormucousmembranes. ▪Fibrogenicdustis ableto inducetheformationof pulmonaryfibrosis,i.e.increasedgrowthof tissuein thelungs.Crystalline silica in the form of quartz, cristobalite or tridymite, as well as the gamma form of aluminum oxide, is considered a fibrogeniccomponent. ▪Theeffectof irritatingdustsis mostoftenmanifestedby mechanicalirritationof themucousmembranesof therespiratory tract, the conjunctiva of the eyes and the skin, and in more sensitive people also by allergic reactions. Some dusts, especiallyoforganicorigin,cancausehypersensitivity,manifestingasbronchialasthma,forexample. (SZÚ, 2008) Effects of dust on the human organism (1) 36 ▪Infectious dust, which contains pathogens trapped on dust particles, can cause serious illnesses, including bacterial and fungalinfectionscausedbybioaerosols. ▪In additionto localeffectson therespiratorysystem,toxicdustscanalsocausesystemicintoxication.Dustscontainingtoxic substancesareabsorbedby theblood,whichthenleadsto an adverseeffecton tissuesandorgans,evendistantfromthe pointof entryof theharmfulsubstance. ▪Carcinogenicdustscancausecancerwheninhaledinpeoplewhoareexposedto thesedusts. (SZÚ, 2008) Effects of dust on the human organism (2) 37 Classification of dusts according to health effect A. Dust with a toxic effect B. Dust without toxic effect C. Dusts with a predominantly fibrogenic effect (quartz, graphite, black coal, coke, talc) D. Dusts with a possible fibrogenic effect (amorphous SiO2, welding fumes, fumes containing chromium (VI), bentonite) E. Dusts with a mostly non-specific effect (cement, marble, brown coal, cinder, limestone, fly ash) F. Dusts with a predominantly irritating effect (linen, cement, fur, flour, spices) G. Mineral fibrous dusts (asbestos, artificial mineral fibers) (Gov Reg 361/2007: A 3, Part A) 6. Occupational diseases Diseases caused by dusts 39 Obsah obrázku text Popis byl vytvořen automaticky Obsah obrázku text Popis byl vytvořen automaticky European Occupational Diseases Statistics (EODS) Obsah obrázku text Popis byl vytvořen automaticky Obsah obrázku stůl Popis byl vytvořen automaticky 40 Occupational Diseases in the Czechia Obsah obrázku text Popis byl vytvořen automaticky 41 7. Health Risk Assessment 49 ▪Health risk assessment for employees who are exposed to dust at work includes a) detecting the presence of dust in the workplace b) detection of dangerous properties of dust that may affect the health of the employee c) ascertaining the level, type and duration of exposure d) description of technological and work operations associated with the development of dust e) use of data on Permissible exposure limits (PELs) f) assessment of the effect of measures taken to protect the employee's health at work g) use of conclusions from already performed medical examinations and other examinations, use of conclusions from extraordinary events and other information from available sources h) conditions under which excessive exposure to dust may occur as a result of an emergency General procedure (1) (Gov Reg 361/2007: §10) 50 ▪The HRA of dust must also include work related to maintenance or cleaning and work during which the employee may be exposed to excessive dust exposure. General procedure (2) (Gov Reg 361/2007: §10) 51 Occupational exposure limit (OEL) (98/24/EC) Permissible exposure limit (PEL) The PEL of dust is the whole-shift time-weighted average of the concentrations of gases, vapors or aerosols in the working atmosphere to which, according to the current state of knowledge, an employee can be exposed in an 8-hour shift or shorter weekly working time, without causing health damage even with lifelong occupational exposure, to endanger his working ability and performance. (Gov Reg 361/2007: §9, par. 1-2) 52 ▪Limit values for aerosols are given in mg.m-3 for actual environmental conditions in terms of temperature and pressure. ▪Limit values for fibers are given in number of fibers/cm3 or in number of fibers/cm3 for actual environmental conditions in terms of workplace temperature and pressure. PELs metrics (Gov Reg 361/2007: §9, par. 9) PELs for respirable and total fractions ▪Permissible exposure limit for the total concentration of dust is denoted PELc ▪Permissible exposure limit for respirable dust fraction PELr (Gov Reg 361/2007: A3, Part A) 53 PELs for dusts (Gov Reg 361/2007: A3, Part A) 54 PELs for dust mixtures Where PELs is the PEL of the mixture, PEL1 to PELn is the permissible exposure limit of individual substances 1 to n, %x1 to %xn is the weight share of individual substances 1 to n in percent.) •The permissible exposure limit of a mixture of dusts (PELs) with different permissible exposure limits is determined by calculation from the permissible exposure limit of individual dusts according to the formula: (Gov Reg 361/2007: A3, Part A) 55 PELs vary within the EU … illustration Obsah obrázku stůl Popis byl vytvořen automaticky (Source : IMA-Europe. Date : December 2020) Obsah obrázku text Popis byl vytvořen automaticky 56 57 ▪Exercices (class/lab) with Sarka Bernatikova Exposure monitoring and measurement Obsah obrázku text, osoba, interiér, elektronika Popis byl vytvořen automaticky Measurement of the inhalable dust fraction (Illustration) Minimum measures - excessive exposure •If, in the event of an emergency, the available technical measures are not sufficient to limit the employee's excessive exposure to dust to an acceptable level, they must be: a) the number of employees at this workplace is limited to those who perform necessary work b) the employee who performs the work according to letter a), provided with PPE appropriate to the dust and the expected level of exposure c) a contaminated area defined by a controlled zone d) the time of dust exposure of an employee who performs necessary work in the controlled zone, reduced to the smallest possible extent e) after the elimination of the causes of the emergency, a control measurement of dust is always ensured 64 (Gov Reg 361/2007: §12) Elimination/Substitution •Change in technology →replace dust-producing technologies with technologies in which lower dustiness or dust is less serious, or no dust is created at all (e.g. shot-blasting vs. sand blasting, water-jet drilling, using pastes instead of powder materials) 65 Engineering controls •Enclosure of dust sources (e.g. hooding of machines, overflows, etc.) •Local extraction (e.g. rock drilling with extraction, grinding with extraction) •Precipitation of dust by water sprinkling or water with wetting agents (note: does not guarantee sufficient efficiency to capture small particles of the respirable fraction) •Dilution of dust by general ventilation of the space (note the direction of air flow should be chosen so that the worker is in a stream of unpolluted air) •Isolating the worker from the dusty environment, for example by placing him in a closed cabin. 66 67 ▪Local Exhaust Ventilation Tato fotka od autora Neznámý autor s licencí CC BY-SA-NC Obsah obrázku osoba, vys avač Popis byl vytvořen automaticky Engineering controls → Illustration (1) https://paragontools.com.au/grinding-concrete-with-angle-grinder/ 68 ▪Maximum covering and hermeticization (i.e. isolation from the external atmosphere) of production facilities (sources of pollutants) Engineering controls → Illustration (2) (Sikorová, 2008) 69 ▪Adjustment of work aids Engineering controls → Illustration (3) (Sikorová, 2008) ▪Separation of the worker from the source (Sikorová, 2008) Administrative controls •Observe the specified method and mode of work (e.g. do not remove deposited dust by blowing with compressed air) •Prevent accumulation of settled dust by cleaning, spraying floors with water, etc. •Limitation of the total working time in a dusty environment: one of the basic measures for the prevention of silicosis and pneumoconiosis of coal miners. For work in mines where there is an increased risk, the highest permissible exposure is determined by an individual decision of the Occupational Health Authority (defined by the number of shifts that a miner is allowed to work in a given job - after it is exhausted, he must be transferred to a non-risky job) 70 (Málek et. al., 2014) 71 ▪Hygiene loop Administrative controls → Illustration (1) (Sikorová, 2008) „Dirty“ changing room „Clean“ changing room Washroom with showers After work shift Leaving work 72 ▪Cleaning –dry vs. wet Administrative controls → Illustration (2) (Sikorová, 2008) Other (Individual) controls •Use of personal protective equipment (PPE) to protect the respiratory system from dust (Note: PPE are always a temporary solution –reducing exposure to dust must be fundamentally addressed by technical and organizational measures) •Preventive medical examinations (introduction, periodic and exit) + followup examinations after the end of „risky“ work 73 (Málek et. al., 2014) NPO_VŠB-TUO_MSMT-16605/2022 Thank you for your attention lucie.kocurkov[email protected] This work is licensed under CC BY 4.0