Exposure to gases and vapors is a significant concern in many workplaces, affecting workers’ health and safety. These airborne hazards can pose serious risks, making it crucial to understand how to identify, monitor, and control them effectively. Today, we’re focusing on the critical topic of exposure to gases and vapors and how to manage these risks in the workplace.
In this post, we’ll delve into the types of gases and vapors commonly found in industrial settings, the health effects of exposure, and practical methods for monitoring and controlling these airborne hazards. By the end, you’ll have a comprehensive understanding of how to protect yourself and your colleagues from the dangers of gases and vapors.
What You’ll Learn
- Types of Gases and Vapors: Understand the types of gases and vapors commonly encountered in various work environments and their sources.
- Health Effects of Exposure: Learn about the potential health impacts of exposure to gases and vapors, including acute and chronic effects.
- Monitoring and Control Methods: Discover effective strategies and best practices for monitoring air quality and controlling exposure to ensure a safer workplace.
Introduction
In the workplace and, indeed, in everyday life, we are exposed to gases and vapors. How do we possibly decide which can harm and which will be exhaled without causing damage to the human body? A good starting point is to use these categories:
- Asphyxiants.
- Irritants.
- Toxics.
Asphyxiants
Simple asphyxiants are gases that can cause a reduction in oxygen concentration by displacement or dilution. Most are odorless, such as carbon dioxide or nitrogen. Chemical asphyxiants, on the other hand, can be present in relatively low concentrations but affect the body’s mechanism for oxygen update or distribution. Carbon monoxide is a byproduct of incomplete combustion and a typical chemical asphyxiant example.
Many accidental or intentional carbon monoxide positioning cases have been documented in the workplace and the community (Kinoshita et al., 2020). Other chemical asphyxiants include arsine, hydrogen cyanide, hydrogen sulfide, and stibine.
Irritants
Irritant gases are not respirable except at very low concentrations. Their action on the respiratory tract depends on their solubility and usually results in uncomfortable burning or stinging. For instance, soluble gases such as ammonia and chlorine dissolve out of the inhaled air in the upper respiratory tract, showing fewer lung effects. Insoluble gases such as nitrogen dioxide penetrate the lungs, causing severe damage. The changing nature of wildfires over recent years has also increased exposure to irritant gases in the general community, with wildfire smoke containing carbon dioxide, carbon monoxide, nitrous oxides, particulate matter, complex hydrocarbons, and irritant gases (Balmes, 2020).
The symptoms from exposure to irritant gases include tearing of the eye, respiratory irritation, coughing, asthma, cloudy vision at high concentrations, other problems with vision, and an acidic taste. In the workplace, the primary irritant gases of concern include:
- Ammonia.
- Chlorine.
- Ethylene oxide.
- Fluorine.
- Formaldehyde.
- Glutaraldehyde.
- Nitrous gases.
- Ozone.
- Phosgene.
- Sulphur dioxide.
Toxics
Toxics can be broadly described as those gases that can cause local or systemic effects in the body and have an occupational exposure standard.
The Movement of Gases and Vapors in the Body
Their partial pressure influences the movement of gases and vapors in the body. Gases move from high-pressure to lower-pressure areas and diffuse into liquids. Therefore, their water solubility is an essential factor impinging on their transportation and excretion throughout the body.
Once the gas has passed through the alveolar capillaries, it must be transported through a medium (e.g., hemoglobin in blood or dissolved into the plasma of blood or the interstitial fluids). However, the rate of gas exchange may also be limited by environmental conditions.
Once the gas enters the conducting or respiratory zone of the respiratory system, it can be absorbed in the following ways:
- By exchange at the body surface (e.g., mucous membranes of the nose and pharynx), where the gas diffuses over a thin, moist respiratory surface
- By exchange within the trachea and its branches
- By passing across the alveolar tissue, where it is exchanged between the medium and blood vessels. This action will depend on the pressure difference (continual gradient) across the tissue.
In the alveoli, gas exchange is driven by its partial pressure gradient. Oxygen passively diffuses from alveolar air space through interstitial fluid into lung capillaries. In normal respiration, carbon dioxide, driven by its partial pressures, diffuses in the reverse direction. Gases also dissolve into the plasma of blood.
Physiological Effects of Exposure to Gases and Vapors
As with other airborne contaminants such as metals, dust, and particulates, the magnitude of risk associated with gas exposure depends on the chemical composition and dose.
The chemical composition will determine the following:
- Level of solubility in different areas of the body.
- The substance’s affinity for specific tissues or parts of the body.
- The target organ.
For instance, ammonia gas in large refrigeration plants is particularly water-soluble. Therefore, the effects of exposure are present in the watery mucous membranes of the eyes, nose, and throat. Ammonia can also impact the respiratory system, even in low concentrations (Mahdinia et al., 2020). Lipophilic substances such as organic solvents are attracted to the skin’s lipid layers and strip off this layer. Carbon disulfide vapor can affect the nervous system and heart. Carbon monoxide has an affinity for hemoglobin in red blood cells that is 250 times greater than oxygen.
Summary
When considering the risks of exposure to gases and vapors, using three categories, asphyxiants, irritants, and toxins, is helpful. Each category may have different health and safety impacts on the body.
Helpful Resources
- Occupational Health and Safety Management: A Practical Approach, by Charles Reese
- Fundamentals of Industrial Hygiene, by Barbara Plog
- Occupational Exposure Limits Blog Post, by Megan Tranter
- Routes of Entry Blog Post, by Megan Tranter
Bibliography
Balmes, J. (2020). The Changing Nature of Wildfires: Impacts on the Health of the Public. Clinics in Chest Medicine, 41(4), 771-776. https://europepmc.org/article/med/33153694
Kinoshita, H., Turkan, H., Vucinic, S., Naqvi, S., Bedair, R., Rezaee, R., & Tsatsakis, A. (2020). Carbon monoxide poisoning. Toxicology Reports, 7, 169-173. https://www.sciencedirect.com/science/article/pii/S2214750019305864
Mahdinia, M., Adeli, S. H., Mohammadbeigi, A., Heidari, H., Ghamari, F., & Soltanzadeh,, A. (2020). Respiratory Disorders Resulting From Exposure to Low Concentrations of Ammonia A 5-Year Historical Cohort Study. Journal of Occupational and Environmental Medicine, 62(8), 431-435. https://journals.lww.com/joem/Abstract/2020/08000/Respiratory_Disorders_Resulting_From_Exposure_to.22.aspx
