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Airborne Contaminants Lab

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Airborne Contaminants Lab Topics Overview of workplace health and its regulation Particulates and microscopy Gases and vapors Monitoring Real time Noise Format ... – PowerPoint PPT presentation

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Title: Airborne Contaminants Lab


1
Airborne Contaminants Lab
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Topics
  • Overview of workplace health and its regulation
  • Particulates and microscopy
  • Gases and vapors
  • Monitoring
  • Real time
  • Noise

6
Format
  • Lecture with break
  • Break
  • Hands-on, with Sheila M Simmons
  • Environmental Health, Safety, and Risk Management
  • http//www.uaf.edu/safety/

7
Practical Application
  • The terms
  • Environmental Engineering
  • Environmental work
  • Often extend to analyzing the workplace
    environment for contaminants
  • hence offering opinions on human health
  • firms often practice in this area.

8
Alphabet Soup
  • EPA
  • OSHA
  • NIOSH
  • AIHA
  • ACGIH

9
Alphabet Soup
  • OSHA, Occupational Safety and Health
    Administration
  • NIOSH, National Institute of Occupational Safety
    and Health
  • AIHA, American Industrial Hygiene Association
  • ACGIH, American Conference of Governmental
    Industrial Hygienists.

10
OSHA and NIOSH
  • Created in 1970s by same act of congress
  • MSHA was earlier,
  • OSHA
  • Law enforcement
  • Department of Labor
  • NIOSH
  • Science
  • Center for Disease Control in PHS.

11
AIHA and ACGIH
  • Industrial hygiene science of workplace health
  • AIHA accredits laboratories
  • ACGIH produces TLVs
  • safe values

12
Occupational Standards
  • OSHA, PELs
  • (CFR, code of federal regulations, on line)
  • PELs
  • ACGIH, TLVs
  • NIOSH, RELs
  • DFK, MAKs

13
TLVs
  • Of the approximately 450 standards
  • 15 have human or otherwise well tested
  • 25 have some animal testing
  • 60 Based on analogy, supposed, or
    traditional.

14
OSHA
  • OSHA main site OSHA
  • 1910 Subpart Z
  • 1910.1000
  • History of Tables
  • ANSI list
  • lawsuits

15
Contaminant Particulates
  • Asbestos
  • Quartz
  • Dust

16
Asbestos is useful
  • Asbestos used since ancient times
  • Fireproof
  • WW II ship building
  • Insulation
  • 1950s Schools
  • Sound proofing,
  • Many materials
  • Strength of fibers, chemical resistant

17
Asbestos kills
  • About 10,000 persons die each year from asbestos
    related disease
  • 1,000 from mesothelioma
  • 4,000 from asbestosis
  • 5,000 from lung cancer
  • (correlated with cigarette smoking)
  • 20 to 40 year latency period
  • Airborne fibers, not parent material

18
Asbestos is regulated
  • OSHA regulates workplace exposures
  • EPA regulates schools
  • EPA regulates disposal process

19
Asbestos Minerals
Insert SiO4
  • Asbestos is a commercial term
  • Polysilicate minerals

20
10 u /-
21
Amphiboles
lisa m applebee structure
  • Amosite (Mg, Fe)
  • Actinolite (Ca, Mg, Fe)
  • Anthophyllite (Mg, Fe)
  • Crocidolite (Na, Fe, Fe)
  • Tremolite (Ca, Mg)

22
Serpentine
  • Chrysotile (Mg)

23
Respiratory Tract
  • Anatomy
  • Physiology
  • Notes on the asbestos diseases

24
Asbestosis
  • Fibrotic lung disease
  • Lungs fill with scar tissue
  • restrictive lung disease, stiff
  • oxygen transport reduced
  • breathing labored

25
Gallery
  • Boston University School of Public Health
  • Breath Taken The Landscape Biography of
    asbestos
  • http//www/busph.bu.edu/Gallery

26
Normal Lung
27
Honeycombing
28
Asbesosis
29
Asbestos, clubbing of fingers
30
Hairdresser, combed from hair
31
Mesothelioma
  • Cancer of the lining of the abdominal cavity
  • Or thoracic cavity
  • Fatal

32

childhood exposure father worked in plant and
died of asbestosis note tumor on right side,
fills with fluid
33
  • Mesothelioma is a rare cancer
  • 2 deaths per million populations
  • But in a study of asbestos insulation workers
    there were 175 deaths from mesothelioma.

34
Lung Cancer
  • 32 of 41 studies indicated statistically
    significant increase in lung cancer of asbestos
    workers
  • Non-smokers were 5-fold higher than non-exposed
  • Smoking asbestos workers were much higher 50- to
    90-fold

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Toxicology, Fiber type
  • Some studies indicate chrysotile can cause
    mesothelioma
  • Most indicate amphiboles, especially crocidolite
  • Some authors have concluded amphiboles are 100
    times more potent than chrysotile in inducing
    mesothelioma.

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particle
fiber
44
Clearance and fiber size
  • Residents of cities breath several hundred grams
    of particles over a lifetime
  • Only a few grams at autopsy
  • Most are cleared from lung
  • Sorting in the airways by aerodynamic diameter
  • Thin fibers penetrate much deeper than round
    particles of similar diameter

45
Clearance mechanism by location of deposition
  • Nasal clearance
  • in from of ciliated, by sneezing or blowing
  • further back swept down and swallowed
  • Tracheobronchial cleared via cilia
  • mucociliary escalator
  • Alveolar
  • macrophage

46
Macrophages
Robins pg. 757
  • Digest particles
  • Carry towards ciliated airway
  • Can wind up in lymph nodes and elsewhere
  • especially is surface route is overwhelmed

47
Macrophage
48
Macrophage
49
Clearance
  • Fibers less than 1 micron cleared half-life of 10
    days
  • Fibers longer than 16 micron, half-life over 100
    days
  • Maximum fiber length of one macrophage about
    16-17 microns

50
Disease vs. fiber length
  • Animal studies
  • Dust rich in f lt 5 ? less lung cancer
  • Dust rich in f gt 5 ? more lung cancer
  • Asbestosis associated f gt 2 ?
  • Lung cancer f gt 5 ?
  • Mesothelioma f gt 10 ?

51
Dose-Response
  • Measured in fibers per cc
  • f/cc
  • Usually states longer than 5 u.
  • EPA uses structures for some purposes
  • but
  • Disease incidence is proportional to exposure.

52
Dose-Response
  • 10 f/cc-yr has been suggests as threshold for
    asbestosis. (0.2 f/cc for 50 years)
  • OSHA PELs (over 5 microns)
  • 12 f/cc in 1971
  • 5 f/cc in 1972
  • 2 f/cc in the early 1980s
  • 0.2 f/cc in 1986
  • Now 0.1 f/cc.

53
Dose-Response, Epidemiology
  • Lowest dose that produced tumors
  • 16 of 19 studies lowest dose was
    gt 10 f/cc yr
  • 14 of 19 studies lowest dose was
    gt 20 f/cc yr
  • 3 studies lowest dose was lt 10 f/cc yr

54
Dose-Response, estimated
  • For 1 excess lung cancer / 10,000 ATSDR
  • For environmental (24 hrs, 365 days)
  • 0.35 f/cc yr (non-smokers)
  • For workers (40 hrs, 50 weeks)
  • 1.5 f/cc yr
  • 0.1 f/cc for 15 yrs
  • 0.05 f/cc for 30 yrs
  • OSHA uses 1 / 1000 for significance, sometimes.

55
ACGIH TLVs
  • Amosite 0.5 f/cc, A1
  • Chrysotile 2.0 f/cc, A1
  • Crocidolite 0.2 f/cc, A1
  • Other forms 2.0 f/cc, A1
  • (New TLVs do not distinguish fiber type

56
Toxicity, Summary
  • Airborne asbestos fibers are a significant health
    hazard
  • 0.1 f/cc (OSHA PEL) for mixed fiber types is
    reasonable
  • Chrysotile is less toxic than amphiboles
  • Fibers less than 5 microns long are less toxic
    than fibers over 16 microns

57
Microscopy
  • PCM phase contrast microscopy
  • and more PCM
  • NIOSH 7400
  • workhorse
  • Cheap, done on job
  • count all fibers longer than 5 microns
  • Does not distinguish asbestos from non-asbestos

58
PCM of Fiber Bundle
59
Microscopy
  • TEM transmission electron microscopy
  • can distinguish asbestos fibers and their mineral
    type
  • expensive (10-15 times PCM)
  • can count small fibers
  • Beam of electrons from bottom
  • just like PCM

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TEM of virus
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SEM
  • Scanning Electron Microscopy
  • Shines the electrons in from the top
  • Scans
  • Shows surface features.

63
SEM
64
Microscopy
  • PLM polarized light microscopy
  • can distinguish asbestos from non-asbestos
  • not used for air samples
  • yields percentage of asbestos fibers in bulk

65
  • Most minerals are translucent (i.e., if the
    mineral grain is thin enough then the light will
    pass through).
  • Analyst examines light that passes through a
    given sample
  • It has interacted with the internal structure of
    the mineral grains.
  • The light emerges from the sample it has been
    altered due to interactions within the mineral
    grains.
  • Each mineral is unique in its composition and/or
    structure so each mineral has a unique affect on
    light when it passes through it.
  • Thus interpreting the emergent light allows a
    geologist to identify minerals with great
    accuracy.

66
PLM of fibers
67
Microscopy
  • NIOSH 7400/7402
  • uses TEM to determine of asbestos in PCM
  • standard method (OSHA hybrid similar)
  • EPA Level II
  • TEM
  • measures small fibers (lt 5 microns) as well as
    larger

68
Summary of Microscopes
  • PCM, Phase Contrast Microscope
  • 400 X, transparent
  • PLM, Polarized Light
  • 400 X, mineral identification
  • Binocular
  • 400 X, dissection and gross identification
  • TEM
  • very powerful, expensive, identification
  • SEM
  • vivid pictures

69
Quartz
70
Quartz
  • Silicon dioxide (SiO2)
  • Occurs in a crystalline or noncrystalline
    (amorphous) form.
  • Crystalline silica may be found in more than one
    form (polymorphism).
  • The polymorphic forms of crystalline silica are
    alpha quartz, beta quartz, tridymite,
    cristobalite, keatite, coesite, stishovite, and
    moganite
  • Some more toxic than others

71
Inhalation of Quartz
  • silicosis, kills 200 300 each year
  • pulmonary tuberculosis (TB), lung cancer, and
    scleroderma.
  • A rare multisystem disorder characterized by
    inflammatory, vascular, and fibrotic changes
    usually involving the skin, blood vessels,
    joints, and skeletal muscle

72
Silicosis
  • Silicosis is similar to asbestosis and emphysema,
    a scarring and hardening of the lungs
  • Mediated by auto-immune problems
  • Can kill relatively quickly in sensitive
    individuals,
  • 2 to 5 years of exposure
  • sandblasters (sand no longer used in US.)

73
Monitoring Silica
  • Particles size
  • Crystal structure
  • Use special techniques
  • XRD Spectrometry
  • IR Spectrometry
  • Colorimetric Spectrophotometry

74
Dust
  • Nuisance Dust

75
How to collect samples
  • Draw known amount of air over a filter.
  • Filter traps particles
  • Dissolve filter for PCM
  • material must permit
  • For silica, use cyclone to separate respirable
    particles
  • For dust, must weight filter before and after
  • Use PVC filter
  • More on air volume a little later.

76
How about gases
  • Hundreds on list(s)
  • What are we monitoring
  • And Why?

77
What Chemical
  • Do we know?
  • Liquid
  • Gas
  • Particle

78
Chemical Properties
  • Major division
  • Hydrophobic vs. hydrophilic
  • Reactive or
  • Flammable
  • Explosive
  • Other chemicals present

79
Process characteristics
  • Sudden releases
  • Ambient
  • History

80
Receptor characteristics
  • Most highly exposed worker
  • All workers
  • Area
  • Work tasks
  • exertions
  • clothing

81
Exposure route
  • Inhalation
  • Dermal
  • Ingestion

82
Air contaminant terms
  • Gas
  • gas at NTP
  • Vapor
  • fume
  • aerosol
  • fog
  • smog

83
Health Hazards
  • Asphyxiation
  • Narcosis
  • Chronic toxicity
  • Acutely toxic

84
Once you know where you are going
  • Regulations may specify
  • Manufactures and suppliers literature
  • Industrial hygiene professional(CIH)

85
Two main divisions
  • Air sampling
  • Take a sample and analyze elsewhere
  • Direct reading
  • real time

86
Explosive
  • Sampling or Direct?

87
Sampling Objective
  • Documenting exposures
  • Regulation compliance
  • Pinpointing sources

88
Acute Hazard
  • Alarms

89
Chronic hazard
  • Usually health

90
Summary of sampling method criteria
  • Sampling Objective
  • Physical and chemical characteristics of chemical
  • Presence of other chemicals
  • Required accuracy and precision
  • Regulatory requirements

91
Summary of sampling method criteria, cont.
  • Portability and ease of operation
  • Cost
  • Reliability
  • Type area, personal, grab, integrated, etc.
  • Duration of sampling and program.

92
Air sampling devices
  • Collect and take to laboratory

93
SKC
  • SKC

94
Breathing zone
6-9
95
Sampling Train
Collection device
Air inlet orifice
Flow rate control
Airflow meter
Suction pump
96
Grab vs. Integrated
  • Vacuum bottles
  • Bags
  • http//www.skcinc.com/prod/tsb.html

97
Integrated
  • Absorption
  • Adsorption
  • Filters
  • Cyclones
  • Electrostatic
  • Inertial
  • Impinger
  • Elutriators

98
Absorption
  • Highly soluble and non-reactive
  • Reactive
  • Similar
  • Gas wash
  • spiral
  • fritted glass
  • glass beads

99
Gas Washing
http//www.skcinc.com/prod/impinger.html
100
Adsorption
  • http//www.skcinc.com/abosor.html
  • Passive http//www.skcinc.com/passamp.html

101
Filters
  • http//www.skcinc.com/prod/filters.html (good
    intro)
  • Respirable dust and selective filtration
  • http//www.skcinc.com/prod/ACyclone.html

102
Calibration
  • Mass of chemical determined in laboratory

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Primary vs. Secondary
  • Secondary
  • Gas meters
  • Rotameters
  • http//www.skcinc.com/prod/frott.html
  • Primary
  • http//www.skcinc.com/prod/sfflow.html

105
Direct Reading
  • Colormetric
  • Length of stain
  • Draeger
  • Tubes
  • /- 25 is an oft quoted reliability
  • Advantages
  • cheap
  • fast

106
Direct Reading, electronic
  • Most use Wheatstone Bridge

Variable R
R
M
R
R
107
Sensor changes conductivity
  • Change with temperature
  • LEL/UEL
  • Change with gas
  • O2, etc.

108
Calibration
  • Gas supply

109
NFPA
  • National Fire Protection Association
  • Standards setting body
  • Flammable Liquid
  • Combustible Liquid

110
Flash Point
  • The flash point is a Temperature.
  • It is lowest temperature at which the liquid
    gives off enough vapor to form an ignitable
    mixture with the air above the mixture.
  • Determined by closed-cup and a variety of test
    methods.

111
Flammable Liquid
  • Flammable has flash point below 100 F (37.8 C)

112
Combustible Liquid
  • Flash point above 100 F.

113
Flammable RangeAKA Explosive Range
  • LEL, Lower Explosive Limit. Minimum
    concentration of vapors, below which propagation
    of flame does not take place. The mix is too
    lean.
  • UEL, Upper Explosive Limit. Maximum
    concentration of vapors, above which propagation
    of flame does not take place. The mix is too
    rich.

114
LEL-UEL
  • Typically expressed as vapor of atmosphere.
  • For many liquids (or gases), the LEL is 6 to 12
  • Table in book lists some in 1 to 2 range
  • Contrast with TLV. Most TLVs are 100s or 1000s
    PPM, while 1 is 10,000 PPM. So if vapor is less
    than TLV, much less than LEL.

115
If you dont remember anything else
  • Cannot use combustion gas meters to check if low
    oxygen

116
Environmental vs. Workplace
117
Chemical EPA(mg/m3) OSHA (mg/m3) Carbon
10.4 58 555 monoxide Styrene 1
425 42500 Carbon 0.7 62 8850
disulfide
118
MSDS
  • Material Safety Data Sheet
  • Manufactures and Suppliers of chemicals must
    supply.
  • Heres a site, Safety
  • Always start with MSDS
  • Available
  • Simple
  • One place
  • Dont rely on, dimethylmercury

119
Summary
  • Must know what you are sampling for
  • Why you are sampling
  • Must calibrate
  • Must keep records
  • Talk to the lab.
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