Your SlideShare is downloading. ×
0
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Air+pollution
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Air+pollution

791

Published on

Published in: Technology, Health & Medicine
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
791
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
35
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Environmental Health Air pollution Week 8 C&D Chapters 15, 24 and 28
  • 2. What is air pollution The result of emission into the air of hazardous substances at a rate that exceeds the capacity of natural processes in the atmosphere to convert, deposit, or dilute them…
  • 3. Factors that affect air pollution • Emissions (traffic, industrial, domestic) • Geography (terrain) • Weather conditions (rain, winds, humidity) • Season • Time of day • Population density • Indoor vs outdoor
  • 4. Types of air pollution  Aerosols – Particulates solid phase • Dust • Ash • Fumes – Solid and liquid • Smoke (from combustion) • Coastal aerosols – Liquid – Aggregate gases (sulfate, nitrate)  Gases COx SOx NOx PAH
  • 5. Six primary or “criteria” air pollutants • Carbon monoxide (CO) • Ozone (O3) • Nitrogen dioxide (NO2) • Sulfur oxides (SOx) • PM2.5 and PM10 • Lead (Pb)
  • 6. Types of air pollution • Individual pollutants • Reducing pollution (SO2) – Acid rain (fog) – Corrosive, eroding • Photochemical pollution – Aldehydes, electrophilic HCs – Oxidative, carcinogenic? • Mixtures and complex patterns
  • 7. Types of Exposures: Continuous Repeated Low High (acute) Respiratory response (endpoints): Macroscopic (e.g. coughing, FEV) Histological Marked variability in responses - susceptibility
  • 8. Combustion pollutants • VOCs • NOx • N-organics • Halo-organics • Metals • CO
  • 9. Sources of combustion • Tobacco • Power plants • Incinerators • Automobiles • Industry
  • 10. Diesel pollutants • Particulate matter – C + PAHs + N-aromatics • Gases – NOx, CO, SOx • VOCs – formaldehyde, acrolein, aldehydes • Respiratory inflammation • Cytotoxicity to airway cells
  • 11. Outdoor air pollution Beijing Delhi
  • 12. Outdoor air pollution Mexico City Santiago
  • 13. Indoor pollutants • Non-specific symptoms • Household vs work space • Sick building syndrome (20% exposed) – Cigarette smoke, combustion products – Organic offgasing (glue, fabrics, furnishings) – Biological agents (infections, allergens) – Additional factors (stress, fatigue, diet, alcohol)
  • 14. Indoor air pollution: Poor countries
  • 15. In the lungs… • Site of deposition along tract • Solubility in respiratory fluids • Reactivity with membranes • Infiltration (alveolar gas exchange) • Level of exposure • Duration of exposure • Respiratory rate • Pre existing conditions (heart, lung)
  • 16. Absorption in lungs • As gas, directly into blood stream • As particles, deposited onto bronchiolar and alveolar surface – Uptake by phagocytosis – Trigger of inflammatory response – Trigger of allergic response – Lung tissue scaring
  • 17. Basic structure of respiratory tract
  • 18. Measurements of lung volume
  • 19. Typical lung volume measurements from normal lung, obstructive airway disease, and restrictive lung disease
  • 20. Normal, Obstructive and Restrictive Patterns of Forced Expiration FVC = forced vital capacity FEV1 = forced expiratory volume at 1st second of active exhalation FEF25-75 = maximal mid-expiratory flow rate FEF75 = forced expiratory flow after 75% of expelled volume
  • 21. Particulate matter pollution • Properties - varied Mixture of solid phase and absorbed materials (organic, inorganic and biological) Carbonaceous core 40-60%, C 7% • Sources – Combustion - oil and coal • Industry • Automobiles – Tobacco smoke – Biomass burning – Metal smelters NAAQS: PM10: 50ug/m3 , annual 150ug/m3 , 24h PM2.5 15ug/m3 , annual 65ug/m3 , 24h
  • 22. Particulates - features • Physical size – Large – Small ~10um – Fine ~2.5um • Aerodynamic diameter (size equivalent of density=1) – Large - local irritation (>100um) – Inhalable (<100um) – Thoracic fraction (<20um) • Coarse PM10 (<10um) • Fine PM2.5 (<2.5um) • Ultrafine (<0.1um) • Chemical reactivity • Shape (fibers) • Water content respirable
  • 23. Deposition of particles in humans
  • 24. Parameters influencing particle deposition
  • 25. Alveolar injury and responses
  • 26. Urban Particulates • In the <2.5um range • Large water content, trace metals, acid gases, organic chemicals, biological • Rather uniform distribution • Include diesel
  • 27. Health effects of particulate pollutants • Eye irritation • Respiratory tract infection • Exacerbation of asthma • Bronchial irritation • Heart disease • Possibly cancer (controversial) (diesel, TiO2, talc, carbon black, toner black) • Elevated hospital admissions, mortality • Causation(s) not fully understood - starting at 10ug/m3
  • 28. Gaseous pollutant features • Chemical reactivity (ozone) • Solubility in water – Soluble • Ambient (NOx, SOx) • Occupational (Hydrochloric acid, Ammonia) – Less soluble • H2S, ozone
  • 29. Gas pollutants - SO2 • Properties – Reacts with H2O and forms sulfurous acid (H2SO3), which oxidizes to sulfuric acid (H2SO4) – Chemical transformation of other pollutants – Responsible for acid rain effect • Sources – Biomass and fossil fuel combustion – Industrial emissions, smelters • Controls – Low-S fossil fuels (clean coal) – Emission control devices • London fog episode (acute) NAAQS: 0.03ppm, annual 0.14ppm, 24h
  • 30. SO2 …continued • Absorption at upper respiratory tract (sulfite, bisulfite) • Health effects (starting at <1ppm) – Respiratory tract irritation, bronchoconstriction – Pulmonary function impairment – Increased air flow resistance – Bronchitis – Exacerbation of heart diseases • Short acute: 2min 0.4-1ppm in asthmatics • Long term, low levels – Impairs immune pulmonary defenses – Susceptibility to infections
  • 31. Gas pollutants - H2SO4 • Product of SO2 – With metals and water --> sulf. Fly ash and acid rain • Protonates biomolecules - membrane damage • Bronchoconstriction • Increased air flow resistance • Mucus secretion protects (buffer) - nose inhalation • Asthmatics are more sensitive • Acidity interferes with mucociliary clearance • Chronic exposure to 100µg/m3 : lower respiratory damage, macrophage mediated
  • 32. Gas pollutants -NO2 • Properties – Oxidant, less potent than O3 • Sources – NO oxidation – High To combustion (automobiles, power plants) – Indoor - kerosene, gas stoves, ETS – Silos in farming (75-100ppm) • Health effects - starting at 1.5-2ppm – Deep lung irritant - terminal bronchioles – Alveolar cells, ciliated epithelia, Clara cells – Similar to ozone but less inflammatory (if < 2-5ppm) – Enhanced infection, suppression of macrophage action – Peaks more NAAQS: 0.05ppm, annual
  • 33. Gas pollutants - CO • Properties – Odorless, heavier than air, stronger binder to Hb than O2 • Sources – Incomplete combustion – Traffic (inside the car, parking garages, tunnels is highest) – Inside cars = 3x urban streets, and = 5x residential streets • Health effects – Asphyxiant – Fatigue, confusion, headaches, dizziness, cardiac function (arrhythmias, angina) – Start at 2.5% COHb (0.5% baseline) (air level 50ppm for 90min) 2ppm COHb, no effect >5ppm COHb, cardiovascular effects 40ppm COHb, is fatal NAAQS: 9ppm, 8h 35ppm, 1h
  • 34. Gas pollutants - O3 Good O3 - stratosphere Bad O3 - troposphere • Properties – Short lived, highly reactive, water soluble – Scrubbed in nasopharynx – Reaches terminal bronchioles and alveoli • Sources – Photochemical reactions • Health effects – Degenerative lung disease – Loss of lung function NAAQS: 0.12ppm, 1h 0.08ppm, 8h
  • 35. Photochemical pollution NO2 NO + O O2 + O O3 O3 + NO O2 + NO2 uv Twist: In absence of HC- the reaction reaches equilibrium Car emitted HC- (PAH) react with O . ….
  • 36. HC- + O . Oxidized free radicals NO NO2 + Aldehydes O3 Balance of photochemical reaction shifts toward O3 build-up!! Hydrocarbons shift photochemical reaction…
  • 37. Photochemical pollution uv O3 NO2 Hydrocarbons O2 O2 . O3 O . H2O 2 (HO . ) The O3 molecule is highly reactive • Ultimate toxicant: • No enzyme can detoxify it • Only protection: prevention of its formation
  • 38. Effects of Ozone on lung function ppb FEV 1 0.5ml (Kinney et.al, 1996) 0.12 - 0.4 ppm for 2-3 h FVC and FEV1
  • 39. ppb ppm 0.30 0.24 0.20 0.18 0.12 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.02 300 240 200 180 120 100 90 80 70 60 50 40 20 LA, until 1998 US-EPA 1h ave Italy study (low exposure) WHO 1h ave EU 1h ave Baseline WHO 8h ave US-EPA 8h ave Effects on lung function observed Ozone levels LA, 1h-ave LA, 8h-ave
  • 40. Ambient O3, TSP and SO2
  • 41. Aldehydes R C Alcoxyl radical RO . (RO . ) Alkoperoxyl radical RO2 . (ROO . ) Nitrous acid HONO Nitric acid HONO2 Hydroxyl radical HO . (HO . ) Hydroperoxy radical HO2 . (HOO . ) H O Some nomenclature of oxidative species
  • 42. Effects of O3 on proteins: Oxidation of: • sulphydryls • amines • alcohols • aldehydes Inactivation/inhibition of enzymes in cellular compartments Aminoacids targets: • cystein • methionine • tryptophan • tyrosine
  • 43. Effects of O3 on lipids: • Polyunsaturated fatty acids (PUFA): primary target of O3 peroxidation of membrane lipids • Most important mechanism of O3-induced injury O3 + PUFA carbonyl oxide H2O Hydroxyhydroperoxy compound HO . H2O2 Lipid peroxidation cascade aldehydes Lipid fragmentation Malondialdehyde (MDA) 8-isoprostane LTB4 (PMN chemotractant)
  • 44. Lipid peroxidation cascade
  • 45. Effects on nucleic acids Electrophiles react with strong nucleophilic atoms of nucleic acids DNA + HO . Imidazole ring-opened purines or ring-contracted pyrimidines Strand breaks Blocked DNA replication Formation of adducts depurination (apurinic sites: mutagenic)
  • 46. Effects of O3 on lung function • Decrement of lung function (FEV1 and FVC1) • Increased airway responsiveness (non specific) • Increased epithelial permeability, injury and loss • May influence allergic sensitization and responsiveness • May increase sensitivity to infections • Induces inflammatory reactions following injury • Exercise increases air flow and penetration
  • 47. Inflammatory oxidative burst Three pathways of HO . generation: • NAD(P)H oxidase • Nitric oxide synthase (NOS) • Myeloperoxidase (MPO) HO . NAD(P)H + O2 O2 . NAD(P)+ H+ Fenton HOOH + H+ +Cl- HOCl MPO Oxidase L-arginine + O2 NO . NOS H+ NO2 . O2 Cl- L-citruline H20
  • 48. The lung’s defenses: Antioxidant molecules:  ascorbic acid (vit. C)  a-tocopherol (vit. E)  uric acid  glutathione (GSH) Metabolic enzymes:  SOD  Catalase  GPX  GSTs
  • 49. • Hazardous air pollutants – Not included in the 6 criteria air pollutants • Include – Organic chemicals (acrolein, benzene) – Minerals (asbestos) – PAH (benzo[a]pyrene) – Metals (Hg, Be) – Pesticides (carbaryl, parathion) • Some are carcinogenic Other air pollutants - HAPs
  • 50. Volatile Organic Pollutants (VOCs) • Sources: Petroleum emissions, fuel combustion, incineration, biomass burning • Account for ~14% of all air pollution • Important factor of indoor air pollution • Types – Aliphatic – Alcohols (ethylene glycol, MTBE) – Aldehydes (formaldehyde) – Aromatic (benzene, toluene, xylene) – Halogenated (TCE, PERC, Methylene Chloride) – Polycyclic (PAHs) – Other (Carbon disulfide)
  • 51. VOCs Health Effects • Alkanes (solvents, varnishes, lacquers) – Irritants, lung and skin – CNS depressants, neuron degeneration, paralysis – Pulmonary edema – React with OH radical in photochemical pollution
  • 52. • Alkenes (gasoline and aviation fuel) more reactive than alkanes - chains, oxides, halogenated HC – CNS effects - cramps, tremor – GI tract - nausea, vomiting VOCs Health Effects
  • 53. Aldehydes • Formaldehyde H2C=O – 50% of total aldehydes – Water soluble – Steep dose-effect: 0.5-1ppm: odor 2-3ppm: mild irritation 4-5ppm: intolerable – Scrubbed in upper respiratory tract, but can also reach deeper – Nasal cancer? (rodents but not humans) • Acrolein H2C=CHCH=O – 5% of total but more irritating
  • 54. Aromatic hydrocarbons (stable, persistent) - Low water solubility, volatile, flammable - Priority pollutants (EPA) • Benzene - most basic – Carcinogen (epoxide, phenol metabolites) – CNS toxicity - narcosis – Irritation (skin, lung) • Toluene (more lipophilic, but faster metabolism) – CNS depressant (narcosis, impaired coordination, headaches) • Xylene (o-, p-, m-) (very lipophilic) – CNS depressant (as above) – Blood cell damage, anemia – Irritant (skin) VOCs Health Effects
  • 55. Polycyclic aromatic hydrocarbons (PAH) incomplete combustion of organic materials, incineration, industry, natural processes – 16 of 126 priority pollutants – Environmental transport, accumulation – Photo - bio- degradation • Carcinogens exposure* (metabolic activation) - • Air exposure 0.02-3ug/day • Cigarette smoke 0.1-0.25ug/cig • Unfiltered cigarettes 2-5ug/day • Vegetarian diet 3-9ug/day • Drinking water 0.2-120ng/day • Soil (urban) 0.003-0.4ug/day VOCs Health Effects * Menzie et.al. 1992, Env. Sci and Technol. Vol. 26: p.1278
  • 56. NAAQS - CAA 1990 • National Ambient Air Quality Standards • ug/m3 or ppm • National Air Quality and Emissions Trends Report
  • 57. NAAQ Standards for six “criteria” pollutants http://www.epa.gov/air/criteria.html Pollutant Primary Stds. Averaging Times Secondary Stds. 9 ppm (10 mg/m3) 35 ppm (40 mg/m3) Lead 1.5 µg/m3 Quarterly Average Same as Primary 0.053 ppm (100 µg/m3) Revoked(2) Annual(2) (Arith. Mean) 150 µg/m3 24-hour(3) 15.0 µg/m3 Annual(4) (Arith. Mean) 35 µg/m3 24-hour(5) Ozone 0.08 ppm 8-hour(6) Same as Primary 0.12 ppm * 1-hour(7) Same as Primary 0.03 ppm Annual (Arith. Mean) ------- 0.14 ppm 24-hour(1) ------- ------- 3-hour(1) 0.5 ppm (1300 µg/m3) Particulate Matter (PM10) Sulfur Oxides Particulate Matter (PM2.5) None None Same as Primary Same as Primary Nitrogen Dioxide Carbon Monoxide 1-hour(1) 8-hour(1) Annual (Arithmetic Mean) *Applies only in limited areas
  • 58. US Regulation history • 1947 CA - Air pollution control Act • 1955 - Truman’s Air pollution control Act • 1963 Federal - Clean Air Act (1967 am) • 1965 Federal - Motor vehicle Air pollution control Act • 1970 The Clean Air Act: national level (EPA) – O3, SO2, NO2, CO, PM, Pb, total hydrocarbons (dropped) • 1970 Lead is banned as fuel additive • 1990 CCA amendment: 118 chemicals, some carcinogenic – Maximum achievable control technology – Additional risk assessment if health effects beyond the MACT level – Emission standards for motor vehicles (CO solution - MTBE new problem) • 1997 New standard for PM2.5
  • 59. Clean Air Mercury and Interstate rules • On March 15, 2005, EPA issued the Clean Air Mercury Rule to permanently cap and reduce mercury emissions from coal-fired power plants for the first time ever. This rule makes the United States the first country in the world to regulate mercury emissions from utilities. • On March 10, 2005, in a separate but related action, EPA issued the Clean Air Interstate Rule (CAIR), a rule that will dramatically reduce air pollution that moves across state boundaries. • Together the Clean Air Mercury Rule and the Clean Air Interstate Rule create a multi-pollutant strategy to reduce emissions throughout the United States. http://www.epa.gov/air/mercuryrule/
  • 60. Epi studies of air pollution Outdoor studies predominantly – Cohort studies (Harvard six cities; American Cancer Society; Adventist Health Study of Smog) – Biomarkers (breath, BAL, blood) – Lung function (FEV1, FVC, FEF25-75) – Symptoms (coughing wheezing, shortness of breath, cardiac function) – Long-term/chronic (confounders) • Retrospective • Prospective – Time series • National Morbidity, Mortality and Air Pollution Study (NMMAPS) • Air Pollution and Health, a European Approach (APHEA)
  • 61. Chronic effects of air pollution • Los Angeles basin: “aging-like” effect on lung function • Netherlands: 12y, SO2 and PM • Rural PA: higher incidence of respiratory symptoms • Harvard Six Cities Study: >15y, 20,000 people SO2 and PM • Overall reduced lung function, bronchitis • Cancer risk: 2000/year vs 100,000/year from smoking - associated with PM/VOC combinations
  • 62. Relative contribution of individual air pollutants to lung cancer rates after removing tobacco smoke cancer (~85%) PIC: products of incomplete combustion
  • 63. US emissions trend for VOCs, NOx, SO2, and PM10, 1900-1990

×