Week 8 Flashcards
(30 cards)
Why is the workplace important?
- Potential for high exposure/long durations
- wide range of possible exposures
- including materials/chemicals that may be uncommon outside of occupational settings - large number of people working
- large amount of time spent working
- 40hrs/week = 24% of time working
what makes the workplace useful for research?
- large number of people working
- relatively easy to identify populations w exposures of interest
- job often a useful surrogate for exposure
- timing/duration of exposure can be assessed relatively easily (people work in consistent, predictable patterns)
- can reveal health links with relevance in community (non-occupational settings) (e.g., diesel exhaust, radon)
4 key issues in occupational health and safety
- international differences in control practices
- different countries have different laws and standards for workplace health and safety (some are strict and some are relaxed)
- Example: A company might relocate its factories to countries with weaker safety laws to reduce costs.
- “Race to the bottom”: This refers to a situation where countries or companies compete by lowering labor standards (including health and safety protections) to attract business. It often results in poor working conditions.
- race to bottom is connected to Environmental Justice: This becomes an issue of fairness—low-income countries or marginalized communities often bear the burden of dangerous work environments, just like they often face disproportionate environmental harm. - Cost/benefit of workplace hazard control
-Implementing safety measures (like proper ventilation, protective gear, ergonomic equipment) can be expensive
- benefits (like fewer injuries or work-related deaths) may take years to realize - People need jobs
- poverty vs health/safety risks
- There’s a difficult balance between avoiding poverty and exposing oneself to risk - The changing nature of work
- “non-standard” or “precarious” employment: This includes temporary jobs, part-time work, gig economy roles (like Uber drivers), and self-employment.
- Why it matters: These workers often lack access to health and safety protections, job security, or benefits like workers’ compensation. They’re harder to regulate and protect under traditional OHS systems.
some workplace exposures
- violence, abuse, harassement
- accidents (motor vehicles)
- noise
- solvents
- pesticides
- airborne hazards (diesel exhaust, carbon monoxide, asbestos fiber)
- ergonomic exposures (vibration, heat)
Pneumoconioses
Group of diseases in which particles accumulate in the lungs
- often the result of dust or fibre exposure in the workplace
Examples:
- asbestosis
- silicosis
- berylliosis
- black lung - coal workers
Effects:
- shortness of breath
- persistent cough
- chest pain
- impaired lung function
- irreversible, can be fatal
Musculoskeletal disorders
Most often affect upper extremities and back
- upper extremities often affected by repetition, force, and vibration
- back often affected by lifting, bending, twisting
- can be acute or chronic
ergonomics
Study of designing and arranging things people use so that the interaction is as safe, efficient, and comfortable as possible.
- fitting the work to the worker
Example: office chairs, factory layouts, etc
Benefits:
- Prevent injuries (like back pain, carpal tunnel syndrome, eye strain).
- Reduce fatigue and discomfort.
- Increase productivity and job satisfaction.
- Lower healthcare and compensation costs for employers.
Some ergonomic risk factors
- Repetition
- risk depends on frequency, speed of movement, force required
- e.g., tendonitis from overuse of a joint - Awkward posture
- working in non-neutral positions - Mechanical contact stress (i.e., pressure point)
- repeated/prolonged contact between hard objects and soft tissues in hands, fingers, feet, etc. - Static posture
- Temperature
- Vibration
Asbestos
- term given to group of six naturally occurring, fibrous silicate minerals
- flexible, strong, durable, incombustible, non-conducting
–> used for fireproofing, insulation, roofing materials, home siding, floor tiles - use in high-income countries peaked in 1970s
–> still used in many low and middle income countries
Asbestos exposure
- exposures for the general public typically low
Higher exposure for: - workers who disturb asbestos containing materials during renovations, equipment installations, etc
- those involved in asbestos abatement (removal, renovation of asbestos containing materials)
- emergency personnel present during/after building damage from fire, earthquake, etc
- some examples of residential exposures after workers clothes carried fibres home
Asbestos health effects
- no acute symptoms
- Cancers (IARC Group 1):
1. mesothelioma - a rare cancer of the mesothelium (primarily the pleura - chest, lung lining)
- long latency period (decades after first exposure)
- spreads rapidly, usually –> death w/in a few years of diagnosis
2. Lung cancer - smoking greatly increases risk (risk ~ 50x that of non-asbestos exposed non-smoker)
3. Stomach, esophagus, colon - asbestosis (a pneumoconiosis)
–> fibrotic lung disease (scarred lung tissue)
–> shortness of breath, reduced lung function
–> associated almost exclusively with occupational exposures
fatality causes include?
- motor vehicle accidents
- violence/assaults
- falls
- struck by objects
- cancers, lung disease
The Changing Nature of Work
Precarious or non-standard employment
- temporary employment, involuntary part-time employment, employment as an “independent contractor”, etc.
- changing relationships between “employers” and “employees”
- often associated with less worker control, lower wages, more dangerous work, and fewer benefits (insurance, unionisation, retirement benefits, etc)
- increasing evidence linking this type of work arrangement with increased risks of physical and mental health problems
occupational noise
- basics of sound
- hearing and hearing loss
- a-weighting
- understanding occupational noise exposure limits
Noise
A leading (preventable) cause of occupational illness
- noise-induced hearing loss accounts for ~ 11% of all occupational illnesses in the US
Results from the Canadian Health Measures Survey:
- 42% of Canadian workers (11.2 million Canadians) report hazardous occupational noise exposure
- approx 1/3 workers had measurable hearing loss (10-17% of workers showed evidence of noise-induced hearing loss)
More on noise
- often thought of as “unwanted” sound
–> but even wanted or desirable sound (like music) can cause hearing loss - potential for noise to damage hearing is related to the noise properties
–> amplitude (loudness)
–> frequency (pitch) - exposure properties
–> duration
–> continuous/transient
Sound
- sound is a longitudinal pressure wave
2 key characteristics of sound:
1. frequency: how quickly the wave oscillate between the pressure “peaks” and “valleys”?
2. Amplitude: how “big” are the pressure “peaks” and “valleys”
Frequency (pitch)
- measured as the number of waves passing a given point per second
- units: Hertz (Hz)
- humans can hear sound between approx 20 and 20,000 Hz
Loudness (Amplitude)
- measured as the sound pressure level
- unit of pressure is the Pascal, but we express loudness as the sound pressure level in units of Decibels b/c its easier to interpret
Decibels (dB):
- sound pressures we encounter vary over several orders of magnitude, from 20 uPa to 150 Pa
- b/c it can be inconvenient to work w such a wide range of values, we convert them to a more manageable scale
- units are relative to the minimum loudness detectable by human ears
–> 0 dB is the very minimum sound pressure level that human hearing can detect
Adverse effects of noise pollution
- noise-induced hearing loss (NIHL)
- often in occupational settings (preventable!)
- temporary (temporary threshold shift; hours to days)
- permanent (permanent threshold shift) - annoyance, nuisance
- non-auditory effects
- sleep impairment
- cardiovascular effects (blood pressure, myocardial infarction, ischemic heart disease)
- reproductive effects
- cognition/academic performance
Mechanisms of hearing loss
- conductive
- outer or middle ear
- problem conducting sound to the inner ear
- trauma, accident, blockage - sensorineural (noise-induced hearing loss)
- inner ear
- noise
- also some drugs, solvents, and metals
effects of hearing loss
- difficulty w communication
- especially in situations w background noise - psychological impacts
- difficulties in relationships
- isolation
- negative self image - impaired ability to work
Threshold shift
hearing loss is often referred as a threshold shift
- threshold refers to the quietest sounds an individual can detect
- when an individual experiences hearing loss (either temporary or permanent), that threshold is shifted up
noise-induced hearing loss (NIHL)
- Notch is common characteristic of NIHL: notch refers to a distinct drop in hearing sensitivity at a specific frequency on an audiogram
- NIHL is usually worst at frequencies around 4,000 Hz
- human speech is between 500-2,000
- so NIHL often not noticed until it is severe
- as duration of exposure increases and/or the loudness of the noise increases:
–> threshold shift increases
–> frequency range of hearing loss widens
