Glossary

A

• Absorption. The process by which hazardous substances enter the body through skin contact. Absorption is a common exposure route for certain chemicals, like solvents, and can lead to local or systemic effects. Proper PPE, such as gloves, can help reduce absorption risks.
• Accumulation. The gradual buildup of a chemical or other hazardous substance in the body over time due to repeated exposure. Accumulation can lead to chronic health effects, especially with substances that have a long latency period before symptoms appear.
• Acute Effects. Health effects that appear quickly after a single exposure to a hazardous substance, such as headaches, dizziness, or skin irritation. Acute effects are typically immediate and reversible once the exposure is controlled or eliminated.
• Acute Exposure. A single or short-term exposure to a high concentration of a hazardous substance, typically occurring over a short period (minutes or hours). Acute exposures can result in immediate health effects, such as respiratory distress, dizziness, or irritation. Acute exposure limits help protect workers from harmful short-term exposures.
• Air Sampling Pump. A portable device used to collect air samples for analyzing contaminants, such as dust, fumes, gases, or vapors, in the workplace. Industrial hygienists use air sampling pumps to monitor and evaluate airborne exposure levels against OSHA permissible exposure limits (PELs).
• Alpha Particles. A form of ionizing radiation emitted from certain radioactive materials. Alpha particles are not highly penetrating and can be blocked by skin or clothing, but they pose serious risks if inhaled or ingested. Proper respiratory protection is essential in environments where alpha particle radiation is present.
• Anthrax. A serious infectious disease caused by the bacterium *Bacillus anthracis*. It can affect the skin, lungs, and digestive system and is a recognized biological hazard in certain occupations, such as agriculture and laboratories.
• Avian Flu. A type of influenza virus that primarily affects birds but can infect humans, posing a risk in agricultural and veterinary settings. Avian flu is an example of a zoonotic disease, where transmission can occur between animals and humans.

B

• Beta Particles. A form of ionizing radiation that is more penetrating than alpha particles but can be shielded by materials like plastic or metal. Exposure to beta particles can cause skin burns and is harmful if ingested or inhaled.
• Biological Agent. Any microorganism, virus, toxin, or other biological entity that poses a risk to human health. Examples include bacteria, fungi, and bloodborne pathogens. Industrial hygienists manage biological hazards in workplaces like healthcare, laboratories, and agriculture through containment, disinfection, and personal protective equipment (PPE).
• Biological Contaminants. Harmful microorganisms, including bacteria, viruses, fungi, and mold spores, that can cause infection, respiratory issues, or other health problems. Industrial hygienists control exposure to these agents through containment, disinfection, and PPE.
• Biological Monitoring. Testing biological samples, like blood or urine, to assess the concentration of hazardous substances in the body. Biological monitoring is useful for substances like lead or mercury, where direct exposure measurements are difficult.
• Bloodborne Pathogens. Pathogens found in human blood and body fluids that can cause diseases, such as hepatitis B, hepatitis C, and HIV. Industrial hygiene practices like using gloves, proper waste disposal, and training help prevent exposure.
• Botulism. A rare but serious illness caused by a toxin produced by *Clostridium botulinum*. It affects the nervous system and can result in paralysis. Industrial hygienists prevent botulism in food-handling environments through sanitation and temperature controls.

C

• Ceiling Limit (C). The maximum allowable concentration of a hazardous substance in the air that workers should not be exposed to at any time. Ceiling limits prevent acute exposure to highly toxic substances. If exceeded, immediate corrective action is required to reduce exposure.
• Chemical Hazards. Substances that pose a risk to health or safety, including gases, liquids, vapors, fumes, mists, and dusts. Industrial hygiene practices such as air monitoring, PPE, and ventilation control exposure to chemical hazards.
• Chronic Effects. Health effects that develop gradually after prolonged or repeated exposure to hazardous substances. Chronic effects include diseases like cancer, respiratory illness, and organ damage. These effects may have a long latency period.
• Chronic Exposure. Long-term or repeated exposure to a hazardous substance at lower levels over an extended period, such as weeks, months, or years. Chronic exposure can lead to long-term health effects, including respiratory issues, cancer, or organ damage. Monitoring chronic exposure levels is crucial for protecting workers' health over time.
• Cumulative Trauma Disorders (CTDs). Injuries caused by repetitive motions, overuse, or sustained pressure over time, such as carpal tunnel syndrome or tendinitis. Proper ergonomics, job rotation, and frequent breaks can reduce CTD risks.

D

• Decibel (dB). The unit of measurement for sound intensity, used to assess noise levels in workplaces. Prolonged exposure to noise levels above 85 dB can damage hearing, making noise monitoring essential in industries like construction, manufacturing, and transportation. Hearing protection programs are often required where noise exceeds OSHA limits.
• Dose-Response Relationship. The correlation between the amount of a substance (dose) and the severity of its effect (response) on an individual. In industrial hygiene, understanding dose-response relationships helps establish safe exposure limits and predict potential health effects from exposure to hazardous materials.
• Dusts. Tiny solid particles that become airborne, often as a result of grinding, cutting, or handling bulk materials. Industrial hygienists control dust exposure through ventilation, local exhaust systems, and dust suppression.

E

• Environmental Monitoring. Sampling and analysis of environmental conditions to detect the presence of hazardous agents like chemicals, pollutants, or biological contaminants. This helps assess potential health risks and guides intervention measures.
• Ergonomic Risk Factors. Conditions in the workplace that contribute to musculoskeletal strain, such as repetitive movements, awkward postures, and heavy lifting. Addressing ergonomic risk factors helps prevent strains, sprains, and cumulative trauma disorders.
• Exposure Limit. The maximum concentration of a hazardous substance that workers can be exposed to over a specified period without adverse health effects. Exposure limits include OSHA’s permissible exposure limits (PELs), short-term exposure limits (STELs), and threshold limit values (TLVs) set by organizations like the American Conference of Governmental Industrial Hygienists (ACGIH).
• Exposure Routes. The pathways by which hazardous substances enter the body, including inhalation, ingestion, absorption, and eye contact. Understanding exposure routes helps industrial hygienists implement effective controls to prevent exposure.

F

• Fibers. Long, thin particles that can become airborne and are often inhaled, such as asbestos and fiberglass. Exposure to certain fibers can cause respiratory illnesses, including lung cancer and asbestosis.
• Frequency Weighting. A method of adjusting vibration or noise measurements to match human sensitivity, such as A-weighting for noise. Frequency weighting is essential for evaluating noise or vibration exposures and developing protective measures for employees.

G

• Gamma Rays. A high-energy form of ionizing radiation that can penetrate deeply into tissues and materials. Exposure to gamma rays is hazardous and requires strict shielding and control measures.

H

• Heat Stress. A physical hazard caused by excessive exposure to heat in the workplace. Symptoms include dizziness, dehydration, and heat exhaustion. Heat stress management includes hydration, rest breaks, ventilation, and monitoring environmental conditions, especially in hot environments like foundries or outdoor construction sites.
• Humidity Control. The regulation of moisture levels in indoor environments. High humidity can encourage mold growth, while low humidity can cause respiratory issues. Maintaining appropriate humidity levels, typically between 30% and 50%, helps protect both indoor air quality and workers' health.

I

• Industrial Hygiene. The science of anticipating, recognizing, evaluating, and controlling workplace hazards that may cause illness or injury. Industrial hygienists work to protect employee health by managing exposure to physical, chemical, biological, and ergonomic hazards.
• Illumination Levels. The measure of light intensity in the workplace, often specified in lux or foot-candles. Proper illumination levels prevent eye strain, improve accuracy, and reduce accidents. Industrial hygienists recommend suitable lighting based on task requirements, ambient conditions, and OSHA guidelines for specific industries.
• Indoor Air Quality (IAQ). The quality of air within indoor environments, influenced by factors such as ventilation, pollutants, humidity, and temperature. Poor IAQ can lead to “sick building syndrome” symptoms like headaches, respiratory problems, and fatigue. Industrial hygienists monitor IAQ through air sampling, filtration, and ventilation controls to protect occupants' health.

J

• Job Hazard Analysis (JHA). A systematic process that identifies potential hazards associated with each step of a job task and determines ways to control or eliminate those hazards. JHA is widely used in high-risk environments, such as manufacturing, construction, and healthcare, where workers are exposed to physical, chemical, or ergonomic risks. Through JHA, industrial hygienists assess tasks step-by-step, evaluate potential exposures, and implement controls (e.g., engineering, administrative, or PPE) to prevent injuries and illnesses.
• Job Rotation. An administrative control method where employees switch tasks or job duties at intervals to reduce continuous exposure to a single hazard. This practice is particularly effective in minimizing exposure to repetitive strain injuries, fatigue, noise, and chemical hazards. For example, in assembly line settings, rotating tasks between workers can help prevent musculoskeletal disorders and reduce cumulative exposure to hazardous substances.

K

• Kinetic Energy. The energy possessed by a moving object. In industrial hygiene, kinetic energy considerations are important for evaluating hazards involving moving machinery, heavy loads, and equipment that can cause injuries upon impact. Industrial hygienists assess kinetic energy risks when implementing safety measures for processes like material handling, where collision with moving equipment could result in serious injury. Control measures may include machine guarding, physical barriers, or safety protocols for moving objects.
• Kinesiological Assessment. An evaluation of body movement and posture, often used in ergonomic assessments to reduce the risk of musculoskeletal disorders (MSDs). By analyzing tasks that involve repetitive motion, awkward postures, or heavy lifting, kinesiological assessments help industrial hygienists recommend workplace modifications, such as adjustable workstations, task redesign, or lifting aids, to prevent injury. This is particularly useful in manufacturing and office settings where workers face repetitive strain.

L

• Latency Period. The time between initial exposure to a hazardous substance and the onset of symptoms or disease. Many chronic illnesses, such as cancer, have a long latency period, making it essential to control exposures even when immediate effects are not apparent.

M

• Mass Concentration. The amount of a specific substance within a unit volume of air, commonly expressed in milligrams per cubic meter (mg/m³). Industrial hygienists measure mass concentration to evaluate worker exposure to dust, fumes, or gases and compare results with OSHA permissible exposure limits (PELs) to ensure compliance and worker safety. Mass concentration measurements are particularly critical in industries like construction and mining, where airborne dust poses inhalation risks.
• Microbial Sampling. The collection and analysis of air or surface samples to detect the presence of microorganisms, such as bacteria, fungi, and mold. Microbial sampling is essential in environments prone to bioaerosols, including healthcare, agriculture, and food processing. Results from microbial sampling guide industrial hygienists in implementing ventilation, humidity control, and sanitation protocols to reduce worker exposure to pathogens. For instance, hospitals use microbial sampling to monitor and control airborne contaminants to prevent infection spread.
• Mutagen. A physical, chemical, or biological agent capable of causing genetic mutations, which may increase cancer risk or lead to hereditary effects. Industrial hygienists manage exposure to mutagens, such as certain chemicals in lab settings or radiation, through engineering controls (like fume hoods) and PPE (like gloves and lab coats). Workers are trained on proper handling to reduce mutagenic exposure risks.

N

• Noise-Induced Hearing Loss (NIHL). Permanent hearing damage caused by prolonged exposure to excessive noise levels, commonly in environments like construction or manufacturing. NIHL prevention includes regular noise monitoring, use of hearing protection, and adherence to OSHA noise exposure limits.

O

• Occupational Exposure Banding. A strategy for categorizing chemicals based on their toxicity and exposure risks when specific exposure limits are not available. This banding method helps determine appropriate control measures for unknown or new chemicals in the workplace.

P

• Permissible Exposure Limit (PEL). The maximum concentration of a hazardous substance allowed by OSHA in workplace air over an 8-hour time-weighted average. PELs are legally enforceable and designed to protect workers from adverse health effects. Employers must monitor and control exposures to keep them within these limits.
• Personal Sound Exposure Meter (PSEM). A wearable device that measures a worker's exposure to noise levels over a work shift. PSEMs are used to ensure compliance with OSHA noise exposure limits and help determine the need for hearing protection in noisy work environments.

Q

• Quantitative Fit Testing (QNFT). A precise, data-driven method to measure the seal effectiveness of a respirator. QNFT measures how much of a test agent can penetrate the respirator and provides a numerical fit factor. This type of testing is required for tight-fitting respirators used in environments with high levels of contaminants, ensuring that respiratory equipment effectively protects workers in hazardous settings like chemical processing and construction.
• Qualitative Fit Testing (QLFT). A pass/fail method used to assess whether a respirator fits properly by relying on the user’s ability to taste or smell a test substance. QLFT is often used for half-face respirators in environments with lower levels of contaminants. It is a simpler, less expensive method but provides a sufficient level of assurance for basic respirator fit where exact measurements are not critical.

R

• Relative Humidity. The ratio of current moisture in the air to the maximum amount the air can hold at that temperature. Industrial hygienists monitor relative humidity to control comfort levels, prevent condensation, and reduce mold growth. Ideal relative humidity is typically maintained between 30% and 50%.

S

• Short-Term Exposure Limit (STEL). The maximum concentration of a substance workers can be exposed to over a short period, typically 15 minutes. STELs are set for substances with acute health risks and help prevent overexposure to highly toxic substances in short timeframes.
• Strains and Sprains. Injuries to muscles and ligaments caused by excessive force, awkward postures, or repetitive motion. Ergonomic improvements and training can help reduce the risk of these injuries.

T

• Threshold Limit Value (TLV). A recommended exposure limit by the American Conference of Governmental Industrial Hygienists (ACGIH) based on research and data. Although TLVs are not legally enforceable like OSHA’s PELs, they are widely used as guidelines to protect workers from adverse health effects.
• Time-Weighted Average (TWA). The average exposure to a hazardous substance over a typical 8-hour workday or 40-hour workweek. TWA helps assess cumulative exposure risks and is often compared against OSHA's permissible exposure limits to ensure a safe work environment.
• Total Particulate Matter (TPM). The sum of all solid and liquid particles suspended in air, including dust, smoke, mist, and fumes. TPM is monitored to assess inhalation risks, particularly in industries like construction, mining, and manufacturing.
• Toxicity. The degree to which a substance can cause harm to humans or other organisms. In industrial hygiene, toxicity levels help determine safe exposure limits and appropriate controls to protect workers from harmful chemicals and biological agents.

U

• Ultraviolet (UV) Radiation. A form of non-ionizing radiation emitted by the sun and some artificial sources like welding torches and UV lamps. Overexposure to UV radiation can cause skin burns, eye damage, and increase cancer risk. In industrial settings, UV protective shields, goggles, and clothing help limit exposure.

V

• Vibration Hazard. Physical vibrations from machinery or tools that can cause damage to nerves, bones, and blood vessels, resulting in conditions like hand-arm vibration syndrome (HAVS). Employers use vibration-dampening tools, task rotation, and PPE to mitigate these risks.

W

• Wet Bulb Globe Temperature (WBGT). A measurement of heat stress in direct sunlight that considers temperature, humidity, wind speed, and solar radiation. WBGT is commonly used in outdoor industries to assess heat-related risks and determine safe work-rest cycles in hot environments.
• Worksite Analysis. A systematic examination of a workplace to identify potential hazards and assess the effectiveness of existing controls. Worksite analysis is a key step in industrial hygiene and is used to identify and prioritize areas for improvement.

X

• Xenobiotic. A chemical substance that is foreign to an organism's natural biology, such as pesticides, industrial solvents, and certain pharmaceuticals. Industrial hygienists monitor xenobiotics in workplaces where workers may be exposed to synthetic chemicals not typically found in nature. Proper handling, ventilation, and PPE are crucial for minimizing xenobiotic exposure, particularly in labs, agriculture, and manufacturing settings where these chemicals are commonly used.
• X-Ray Diffraction (XRD) Analysis. A laboratory technique that determines the mineralogical composition of materials. In industrial hygiene, XRD is used to identify hazardous particles like silica and asbestos in dust samples, allowing hygienists to assess and control inhalation risks. For example, in mining or construction, XRD can confirm the presence of silica in dust samples, helping to implement controls like ventilation and PPE to minimize exposure.

Y

• Yeast and Mold Count. The process of measuring the concentration of yeast and mold in air or surfaces, often in workplaces prone to organic contamination, such as food processing facilities and agriculture. Yeast and mold counts help industrial hygienists manage air quality, reduce respiratory risks, and ensure hygienic standards. For instance, food production facilities perform yeast and mold counts to prevent contamination that could impact both worker health and product safety.
• Yield Strength. The maximum stress that a material can withstand without permanent deformation. Yield strength is important in industrial hygiene when assessing the safety of materials and equipment used in manufacturing, construction, and mechanical work. Understanding the yield strength of materials informs safe handling and load limits, preventing accidents due to equipment failure or collapse.

Z

• Zero Exposure. A goal in industrial hygiene to eliminate any detectable level of hazardous substances in the workplace. Zero exposure is achieved through hazard elimination, substitution, or engineering controls and is most effective when used as the first line of defense. For example, substituting a toxic solvent with a non-toxic alternative can lead to zero exposure, enhancing workplace safety and health outcomes.
• Zone of Contamination. The designated area within a workplace where contaminants are present and pose a risk to employees. Industrial hygienists identify and control these zones by establishing barriers, restricting access, and using engineering controls like ventilation. For example, in chemical processing plants, contaminated zones are monitored and managed to prevent the spread of hazardous substances and to protect workers in adjacent areas.