Inhalation exposure
Inhalation is a major route of exposure that occurs when an individual breathes in polluted air which enters the respiratory tract.
In this way, the mechanism of pollutant uptake by the respiratory system can be used to predict potential health impacts within the human population.
The fraction of this ambient concentration that is inhaled by a person depends mainly on their location (indoor or outdoor), distance to pollution sources and their minute ventilation.
Trips to other locations and physical activity level are mostly neglected although some recent studies have attempted to use portable and wearable sensors.
The remaining pollutant that is transported through the liquid layer, making contact with the respiratory tract tissues is the fraction of bioavailability, called the effective dose.
The six criteria are the following: particulate matter (PM), nitrogen oxide NO2, ozone O3, sulfur dioxide SO2, carbon monoxide (CO), and nonmethane hydrocarbons (NHMC).
Coarse particles, originating from natural sources such as dust, sand and gravel, tend to deposit in the nasal-pharyngeal region.
Fine particles, derived from anthropogenic sources such as fossil fuels and smoking, typically deposit in the pulmonary region.
Most gas exchange occurs in the pulmonary region due to the alveoli, which contain a large surface area.
Scientists have identified a positive correlation between particulate matter concentrations being the causative factor of respiratory and cardiovascular disease.
Soluble particulate matter can be highly detrimental to the respirator tract because of their ability to dissolve into the mucus or surfactant layer.
Insoluble PM, such as lead particles, deposit in the nasal-pharyngeal region and can be cleared by blowing, sniffling, or spitting.
Insoluble particles that enter the pulmonary region cause swelling of the alveoli, coughing, and shortness of breath.
Since the gas takes time to build up in the pulmonary region, an inhaled concentration of 600 ppm would cause a headache and reduce mental capacity within an hour, without any other symptoms.
A baseline level of carboxyhemoglobin, (COHb) is contained in the blood due to small quantities of CO as a by-product in the body.
An example of this can be seen when any type of vehicle is "removed" altogether from a workplace to rid the area of pollutant gas production from burning fossil fuels.
Engineering Controls can be seen with "tools and equipment" being installed and implemented to remove harmful products created by various processes.
Administrative Controls can be employed to reduce inhalation exposure often through methods to have workers only perform their tasks in a certain way.
[4] IDLH atmospheres occur where the contamination of pollutant gases creates an environment where individuals would be severely injured or killed without proper respiratory protection.
All pollutant gasses have their unique characteristics in terms of IDLH concentrations, side effects, and carcinogenic nature,[6] among other traits.
This often occurs due to asphyxiant [7] gases like CO2 displacing the oxygen out of the surroundings below a level that can be safely inhaled by an individual.
With this, atmospheric monitoring systems are often employed to help better understand oxygen concentrations and toxic or poisonous gas exposure.
As mentioned previously, any area with restricted means of egress and is not intended to support occupancy can be a confined space.
Some chemicals have severe carcinogenic properties even at quick, very low concentrations while others require frequent and intense exposure to observe cancer-related issues.
[10] In the U.S., many levels of government and agencies recognize the severity of pollutant gases, carcinogens, chemical exposure, and the effects they can cause.
Some of the agencies that research and/or regulate chemicals include OSHA,[11] NIOSH,[12] and CDC,[13] to name a few along with numerous other state and professional organizations.
The "First Aid Measures" section details what a person affected by the chemical should do to reduce injury or illness from their exposure.
The "Control Parameters" section details the exposure limits, often in ppm, of how much a person can be exposed to before they experience injury or illness.
The "Personal Protective Equipment" (PPE) section describes what garments should be worn to mitigate exposure to the chemical.
