Toxic responses of the lung

1. Toxic responses of the lung Environmental health and toxicology – Lecture 7

2. Lecture Objectives • Understand the function of respiratory system • State natural mechanisms against airborne hazards • Be aware of occupational lung diseases • Understand occupational airborne hazards • Understand health effects linked to PM • State mechanism involved in causing PM-related health effects

3. Content • Respiratory system • Stages of lung toxic responses • Workplace exposures • Occupational lung diseases • Air borne hazards • Smoking • Air pollution • Particulate Matter

4. Quiz • Coughing! • But inability to cough can lead to infection. Deep breathing exercises may help keep finer structures of the lungs clear from particulate matter, etc. Words: mucus粘液, saliva唾液, debris碎片 What is the body's main method to remove dust, mucus, saliva, and other debris from the lungs?

5. Respiratory System • No oxygen -live only minutes • Every cell needs constant supply of oxygen • Lungs link to supply of life-giving oxygen

6. Respiratory System • Normal breathing – online flash http://www.airinfonow.org/html/lungattack/lungplay.htm

7. Lung anatomy Words: trachea气管, cartilage软骨, pharynx咽, larynx喉

8. Lung anatomy • The blind sacs in the lung tissue, called alveoli, consist of several types of cells. Each alveolus has a network of capillaries that carry blood in the lungs.

9. Lung anatomy line the alveoli and secrete a substance called "surfactant." Surfactant coats the alveoli and provides pressure to keep them from collapsing. Without surfactant the alveolar surfaces tend to stick together which causes the alveoli to collapse. the largest, thin cells that form the walls, or septa, of the alveoli. II 型肺泡上皮细胞 I 型肺泡上皮细胞 成纤维细胞 part of the connective tissue in the lungs. 巨噬细胞 毛细管 scavenger cells that work to keep the lung free of "foreign" materials.

10. Development of the alveoli

11. Lung volume 补吸气量 肺活量 肺总容量 潮气量 补呼气量 功能余气量 余气量

12. Tidal breath • Tidal breathing is the inhalation and exhalation method by which mammals breathe. • It refers to the amount of air used when at rest and when breathing functions are automatic. • It is measured by doctors trying to study or diagnose respiratory and other health problems.

13. Natural mechanisms against airborne hazards • Fine hairs in nose • front-line barrier • filter • exercise/hard work • Cough reflex – clears trachea & main bronchi • Special cells – destroy bacteria & viruses • Ciliary cells – few hours to expect foreign material • Innermost areas of lungs – much longer to clear out Words: Cilia 纤毛

14. Respiratory System • Lungs that receive prolonged &/or repeated exposure to air contaminants eventually cannot keep up with the rate of deposition &/or constant irritation. • Result: contaminants accumulate contributing to the development of Occupational Lung Diseases. Diagram- black asbestos fibers- exposure standards to be less than 1 fibre/cm3 for 8 hr exposure.

15. Stages of lung toxic responses • Stage 1 Exposure through inhalation • Stage 2 Action of agent on component of the cell starting with binding • Stage 3 Response of lung to loss of function • Stage 4 Transport of agents to other sites of action

16. Toxic actions are based on four factors: • Pattern of inhaled exposures • Ability of the agent to bind to cellular components • Capacity for cellular repair • Capacity to detoxify the agent and excrete from the body.

17. Disorders of the respiratory system • Obstructive conditions阻碍性肺病 • Restrictive conditions (interstitial lung diseases)限制性肺病 • Vascular diseases 肺血管疾病 • Infectious, environmental diseases 感染性肺病

18. Obstructive conditions • diseases of the lung where the airways (i.e. bronchi, bronchioles, alveoli) become reduced in volume or have free flow of gas impeded, making it more difficult to move air in and out of the lung. • e.g., emphysema, bronchitis, asthma Words: emphysema肺气肿, bronchitis支气管炎, asthma哮喘

19. Restrictive conditions • a loss of lung compliance, causing incomplete lung expansion and increased lung stiffness. • e.g., fibrosis, sarcoidosis, alveolar damage, pleural effusion Words: fibrosis肺纤维化, sarcoidosis肺结节病 alveolar damage 肺泡损伤, pleural effusion肺积水

20. Vascular diseases • describes any condition that affects the blood circulation in the lungs. • e.g., pulmonary edema, pulmonary embolism, pulmonary hypertension Words: pulmonary edema肺水肿, pulmonary embolism肺栓塞 pulmonary hypertension肺高压

21. Infectious diseases • communicable diseases, or contagious diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism. • e.g., pneumonia, tuberculosis, asbestosis, particulate pollutants Words: pneumonia肺炎, tuberculosis肺结核, asbestosis石棉沉着病

22. The Spectrum of Lung Disease 鼻炎 喉炎 Restrictive lung disease Chronic Obstructive Pulmonary Disease 慢性阻塞性肺疾病

23. Soreness of the throat 扁桃体

24. Bronchitis Chronic or acute inflammation of the mucous membrane of the bronchial tubes.

25. Emphysema • A pathological condition of the lungs marked by an abnormal increase in the size of the air spaces, resulting in laboured breathing and an increased susceptibility to infection. • It can be caused by irreversible expansion of the alveoli or by the destruction of alveolar walls.

26. Asthma • A chronic respiratory disease, often arising from allergies, that is characterised by sudden recurring attacks of laboured breathing, chest constriction, and coughing.

27. Pulmonary Edema • Pulmonary Edema is Abnormal fluid accumulation within the alveoli and the interstitial tissues of the lungs.

28. Occupational health trends • Occupational lung diseases: • workplace exposure to irritating or toxic substances- may cause acute or chronic respiratory ailments.

29. Occupational lung diseases • Occupational Asthma • Reactive Airways Dysfunction Syndrome (RADS) 反应性气道功能障碍综合征(asthma-like syndrome developing after a single exposure to high levels of an irritating vapour, fume, or smoke. ) • Emphysema • Chronic Bronchitis (repeated infections and/or exposure to irritants such as fumes/dusts, oil aerosols, gases, smoke)

30. Occupational lung diseases • Pneumoconiosis (PM 5μm) • Hypersensitivity Pneumonitis (organic dusts-fungi, animal proteins, vegetable proteins) • Granulomatous Disease (TB, toxins-Berylliosis best known occupational example) Words: Pneumoconiosis肺尘症, Hypersensitivity Pneumonitis过敏性肺炎 Granulomatous Disease肉芽肿病, Berylliosis铍尘肺

31. Occupational lung diseases • Pneumonia – toxic process or more commonly infections (health care, child care & animal care workers) – fungi, bacteria, viruses, other microorganisms • Occupational Lung Cancer – smoking, coal tar, pitch volatiles, mustard gas, arsenic, asbestos, radium, petroleum, chromates, uranium

32. Pneumoconiosis • Depending upon the type of dust, the disease is given different names: • black lung coal, carbon • Asbestosis asbestos • Silicosis silica • Bauxite fibrosis bauxite • Berylliosis beryllium • Siderosis iron • Byssinosis cotton • Silicosiderosis mixed dust containing silica and iron

33. Acute respiratory irritation • It results from the inhalation of chemicals: • Ammonia, chlorine, nitrogen oxide in the form of gases, aerosols • If such irritants reach the lower airways it damage the alveoli’s & pulmonary edema may occur • Although the effect of irritants are usually short lived, some may cause chronic alveolar damage or airway obstruction.

34. Occupational lung hazards • Classification of work hazards • Physical • Mechanical • Chemical • Biological • Psychosocial

35. Hazard and Risk • Hazard • potentially harmful • Risk • probability of harm • (quantifiable as risk assessment)

36. Airborne hazards • Mineral dust • Organic dust • Chemical dust • Fumes • Mists & sprays • Vapours • Radiation • Biological hazards

37. Airborne hazards – Mineral dust • Dusts & mineral fibres from stones, rocks, ores • Sources • Mining, quarrying, tunnelling, blasting, smelting, grinding, milling, processing, drilling, abrading • Industries • mines, quarries, foundries • Lung effects • pneumoconiosis (asbestosis, silicosis, black lung) chronic bronchitis, emphysema, fibrosis, cancer

38. Airborne hazards – Organic dust • Dusts formed from living materials-micro-organisms, plants, animals & natural products like wood & leather. • Sources • Wood, cereal grains (planting, harvesting, storing, transporting, processing), animal husbandry (droppings, dander, feathers) • Industries • Agriculture, manufacturers (furniture/ drugs), millers, bakers, chemists • Lung effects • Hypersensitivity reactions-occupational asthma or hypersensitivity pneumonitis-permanent obstructive disease, diffuse lung fibrosis. Wood dusts -cancer

39. Airborne hazards – Chemical dust • Synthetic chemicals (powder form), such as pesticides, pharmaceuticals, dyes, bleaching agents, detergents, paints • Sources • Any contact from making, packaging, applying, weathering • Industries • aircraft building, pulp mills, chemical, breweries, foundries, hairdressing, health care, labs, manufacturing (paints), paint sprayers • Lung effects • Depends on toxic properties of specific chemicals-irritants, allergens, cancer

40. Airborne hazards – Fumes • Very small solid particles formed when hot vapours cool rapidly & condense • Can give off hazardous gases • Act like very fine mineral dust in lungs • Sources • High heat processes • Industries • Smelting, arc-welding, furnace work • Lung effects • Difficult to assess effects of separate materials since several hazards present at same time. Can lead to emphysema & lung cancer.

41. Airborne hazards – Mists & sprays • Liquid droplets suspended in air or other propellant gas. • Sources • Cleaning products, pesticides, paints, cosmetic products, rust removers • Industries • Cutting, grind, spraying and pickling operations, electroplating • Lung effects • The finer the spray, the deeper into the lungs it goes. Effect depends on material, concentration and temperature.

42. Airborne hazards – Vapours • Vapours hang out with parent liquid • Sources • Inorganic-high boiling points, don’t vaporise at room temperature-aren’t usually associate with lung disease • Organic-many vaporise at room temperature-used as solvents (ketones, alcohols, acetates, aromatic hydrocarbons) • Lung effects • enter body through lungs • damage to other organs more so than lungs • pulmonary edema & tracheobronchitis.

43. Airborne hazards – Radiation • Radiation • Non-ionising radiation (electromagnetic waves-infrared, ultraviolet, microwave, laser, radar, radio frequency) • Ionizing radiation (alpha, beta, gamma rays, neutron particles & x-rays) • Sources • Mining radioactive ores • Industry • Medicine, power plants, equipment used in industry (high energy electrical equip., lasers, microwaves, radar) • Lung effects • Electromagnetic waves can cause thermal burns. Ionising radiation can cause cancer.

44. Airborne hazards – Biological hazards • Bacteria, viruses, fungi • Sources • Health care & child care facilities, poorly maintained ventilation systems, biological research labs, animal care & processing facilities • Lung effects • Depends on type of hazard. Can be minor allergies & lung infections to cancer. Vaccinations for some.

45. Smoking • Smoking contributes to lung disease • Impairs lungs’ natural defense mechanisms –irritates airways & inhibits work of ciliary cells • Oxidants are one toxic component of cigarette smoke. They can damage the DNA of lung cells much like the sun damages skin cells.

46. Smoking • Smoking is leading cause of serious lung disease & certain types of cancer • Synergistic effect with other pulmonary carcinogens (asbestos, chromium/uranium compounds, arsenic) • Increases lung cancer risk • Smokers develop lung disease & cancer more readily & diseases progress more rapidly

47. Air pollution • Air pollution may be defined as the presence in the air (outdoor atmosphere) of one or more contaminants or combinations thereof in such quantities and of such durations as may be or tend to be injurious to human, animal or plant life, or property, or which unreasonably interferes with the comfortable enjoyment of life or property or conduct of business.

48. Who is at risk? • Everyone faces increased risk of harm from exposure to these hazardous air pollutants. • Particularly: • Children and teenagers; • Older adults; • Pregnant women; • People with asthma and other lung diseases; • People with cardiovascular diseases; • Diabetics; • People with low incomes; • People who work or exercise outdoors; and • Others with existing health problems

49. Industrial Toxicants that Produce Disease of the Respiratory Tract

50. Fine particles, or haze, restrict our ability to see long distances Unadjusted Hourly conc. of fine particles – 4 g/m3 Hartford Oct. 8, 2002 4 p.m. EDT Unadjusted Hourly conc. of fine particles – 24 g/m3 Hartford Oct. 2, 2002 4 p.m. EDT