PPE: Personal Protective Equipment

Whether you are a welder working with extremely dangerous temperatures and liquid metal, or an electrician working in high voltage areas, personal protective equipment (PPE) is a must. Many in professions where dangerous are not as obvious may take this for granted. However, almost any employer in present day now has an MSDS sheet which outlines safety protocols during an emergency. Despite where you may work or what your lifestyle is, danger and risk is a constant in every day life. Taking extra precaution to protect yourself is beneficial.

WHAT IS ASSIGNED PROTECTION FACTORS?

Assigned Protection Factors (APF), as defined by OSHA, is the workplace level of respiratory protection that a respirator is expected to provide to the employees when the employer implements, effective respiratory protection program as specified by this section. 

WHAT IS MAXIMUM USE CONCENTRATION?

Maximum Use Concentration (MUC), as defined by OSHA, is maximum atmospheric conditions of a hazardous substance from which an employee can be expected to be protected when wearing a respirator. This is determined by the Assigned Protection Factor of the respirator/class of respirators.

PENETRATION

Penetration is defined as: how well a chemical or liquid substance has physically penetrated a material based on visual observation or detection.

PERMEATION

Permeation rate is the rate at which a chemical or substance passes through a material at a molecular level.

DEGRADATION

The physical changes to a material caused by a chemical or substance is known as degradation. This can be illustrated in change in color, swelling, wrinkling, and many others. This can also occur in live plants, and other biodegradable materials in the environment.

TYPES OF RESPIRATORS

• Air Purifying Respirators- use canisters or filters to remove contaminates from the air by passing ambient air through the air-purifying element before reaching the user.

• Particulate-Filter Respirators- this respirator captures and traps particles in the air. However, it do NOT protect against gases and hazardous vapors. 

• Chemical-Cartridge Respirators- filter categories: absorption, adsorption, catalysis

QUALITATIVE versus QUANTITATIVE

Qualitative fit testing is a self-reported and sometimes visual affirmation of involuntary response (e.g., grimace) to strong respiratory irritants and substances. An individual doing a qualitative test would be exposed to various chemicals and substances and if their mask is not properly fitted they would smell the chemical and respond with a grimace. 

Quantitative fit testing is a little more accurate since there is data collected and systematic testing conducted. There is a measurable fit factor, a controlled negative pressure as well as a condensation nucleus counter (PortaCount). Some examples include: normal and deep breathing, head nods, reciting rainbow passage. 

WRITTEN HAZARD ASSESSMENT

A hazard assessment is an evaluation of a workplace and it's potential risks and dangerous that an employee could encounter while doing their job. We often evaluate many things in our life and our workplace is one of those major considerations. 

An example of a written hazard assessment categories are listed below: 

Identify the Hazards

Falling Objects Hazards

Chemical Hazards

Potential Exposure to Bodily Fluids

Biohazards

An example of a full hazard assessment can be found here. 

Noise Quality and Hearing Loss Prevention

Noise is often an element of our environment that we take for granted. In some cases, may even intentionally abuse it, by playing our music loudly, or taking risks that otherwise we may not take if we better understood the longterm consequences. I often think that we choose to take the risks, because the consequences are delayed. Meaning, we do not face the consequences of our actions until 10-20 years later in life when our hearing begins to deteriorate. However, there are acute incidents where we may risk severe hearing loss if we are not careful. This is why noise protection and safety guidelines are very important.

NOISE REDUCTION RATING

Many safety equipment manufacturers implement the noise reduction rating on their products to help provide consumer safety. This rating is monitored by OSHA and is often used as a tool to measure safety and risk levels of noise in dB. It is a guideline only and cannot guarantee an exact reduction in a noisy environment. That is due to many circumstantial factors that are not controllable. 

HOW DOES OSHA CALCULATE NRR?

OSHA has a standard formula that is used to calculate the NRR. This calculation is a time weighted average (TWA) equation where you take the dBA and subtract 7 and x it by 50%. That will give you the NRR. 

STANDARD THRESHOLD SHIFT

The standard threshold shift is known in the occupation safety field as a change in the hearing threshold of an employee's baseline hearing. The average loss is of 10dB or more at 2000, 3000, and 4000 hertz. This is an important element to address and be mindful of, because this directly correlates to the ability (or inability) for communication. This hearing loss occurs in the frequencies where humans speak and hear and are essential for communication. 

5dB EXCHANGE RATE

This is a ratio where for every 5dB increase, a person's duration of exposure is cut in half. This is allows for a better baseline on permissible exposure limits and how to regulate the safety of the workers in the company. Keeping in mind, this exposure is constant without pause. For example, in an 8 hour time period, exposure can be around 90 dBA. If the dBA increased to 95, the exposure (cut in half) would then be only 4 hours. If it increased to 100dBA, the maximum allowable exposure time is then cut to 2 hours. 

ADVERSE HEALTH EFFECTS FROM HIGH NOISE ENVIRONMENTS

The above sound meter photos are measurements taken during different environments. The top dB reading was taken in a short-burst time where the lawn mowers were passing by the house. It fluctuated from 101 dB to 70 dB. I never realized just how loud a lawn mower was until I saw this reading on the meter. I couldn't believe that I had never worn ear protection before when being around lawn mowers even for a short period of time. This information will actually change how I view my hearing protection and will view it more importantly. 

The below meter was taken in the living room with 2 windows open on the first floor. The ambient outdoor sounds and no TV on ranged between 48dB-56dB. 

Benzene Sampling-Sampling Air

WHY SAMPLE AIR?

Air is all around us. We need it to survive and our environment needs it to sustain life. When we think about the enormous dependency we have on the element of air, one might pose the question: is all air created equal? 

We have addressed the quality of air in a previous blog, and in order to accurately illustrate air quality  among descriptions within air, we use sampling procedures. Sampling systems are found in many arenas in our culture. For example, samples are taken from biological species at a crime scene during police investigations. Another example, samples are taken in laboratories across the country, daily for medical, technological, and other purposes. 

So, what is a sample, and in this context, why sample air?

A sample is often defined as testing or to measure something. However, when running tests or sampling, the object in question is often destroyed or runs a high risk of being altered and changed. We sample air to obtain measurements and identify chemical compound levels within any given sample. 

PUMP CALIBRATION AND 8 HOUR VOLUME

Once there is a sample of air, the volume must be accurately known and tested. Pump calibration is a technique used to obtain accuracy of the air sample. This is in part due to air temperate and pressure can alter and skew results. An item called a sampling train, is usually used to connect the pump to the calibrator. 

8-hour volume- this calculation allows us to determine how much benzene is present in any given 8-hour time period. To do this, we must make several conversions to get our final solution to represent the units of PPM-parts per million. 

Our first calculation would be to multiply our 8 hours (480 minutes) by 2 to get= 960 liters. This represents only the amount of air flowing through the pipe. 960 divided by 1000 will give us the cubic meters answer of 0.96. Then to convert this 0.96 cubic meters into parts per million, we will take the 2.39mg of benzene on tube and divide it by 0.96. Our answer is then multiplied by 24.45 and then divided by 78 which is the molecular weight of Benzene. 

Our final answer is ~0.75ppm, which is below the 1ppm by OSHA's standard. This represents that we are underexposed and do not surpass the upper 

Time Weighted Average- this is a concept which illustrates a particular concentration of substances expressed over a period of time. This allows for us to understand the overall concentration and then can represent that in OSHA's OEL. 

In our above calculation example, our 0.75ppm was our TWA and this provided us a baseline to claim under or overexposure according to the permissible exposure limits by OSHA. 

BREATHING ZONE

The breathing zone is particularly important in sampling because it increases the accuracy of the testing procedures. Our breathing zone is subjective and unique to each person. This will determine the amount of exposure (or lack thereof) because our breathing zone moves along with us. So, for an 8-hour period someone may be up on a scaffolding working, while another person may be very close to the ground, kneeling down working on some ground wiring. That's an example of how our breathing zone can influence and effect the results of the sample. 

OSHA STANDARD-OEL

OSHA has admittedly reported that they acknowledge many of their permissible exposure limits (or OEL's) are outdated and in need of revisiting and updates. The OEL is a legal limit for exposure in the United States where an employee can safely be exposed to a chemical substance or loud noise. 

NIOSH METHOD NUMBER

The use of method numbers allows for classification of substances and organization. Method numbers identify a specific chemical or element and then provide further information on the particular substance.

FLOW RATE, SAMPLE STABILITY, SAMPLE

• Flow rate describes a volume of fluid that passes per unit time, and is often represented by the symbol of Q. (sometimes capital V). 

• Sample Stability refers to the un-changing state of a particular sample. Understanding that chemical and biological processes can be altered and changed over time, within the environment or internally. With sample stability we are attempting to hone in on a sample and maintain the integrity of a sample over time. 
• Sampler- various equipments used for collection, calibration, and sample testing
• Blanks- Media and Field blanks report varying results depending on substance sampled. They are required so as to provide accuracy in results and to identify potential contaminants during storage and sampling procedures. Minimum of blanks is defined by how many samples are taken during a time period. 

Airborne Hazards

AIRBORNE HAZARDS ARE ALL AROUND US

Whether it's occupational, by choice, or a matter of circumstance from the environment we live in, we are all exposed to airborne hazards daily. Some may be more detrimental to our health than others, but it is pose for concern and discussion as to how dangerous this hazards really are and by what mechanisms they impact our health. Various factors that will be discussed are: 1) how the size of the containment impacts our bodies, 2) the locations of the respiratory tract infected, and 3) the mechanisms in which our bodies attempt to cleanse or rid the hazards. There are state and federal regulations that protect us all and provide us the rights to work in a safe and hazard free environment!

AIRBORNE HAZARDOUS MATERIALS BY SIZE

There are five major airborne hazard categories that are classified by size. They are as follows:

• Vapors (gaseous phase of liquids)
• Dust (aerosals composed of dry particles)
• Gases (most common airborne contaminate)
• Fumes (materials heated to a point where they become a gas)
• Mists (airborne droplets)

REGIONS OF RESPIRATORY TRACT

Regions of the respiratory tract all influence various different components of our air quality and the hazards that are encompassed within them. The regions are: inhalable fraction (known as the nasopharyngeal region (NP); thoracic fraction (known as the tracheobronchial region (TB); and the respirable fraction (known as the pulmonary region). Our nasopharyngeal region is essentially the region that intakes almost 100% of all of our environmental air and along with it, potential hazards. Where the contaminants travel down to, is dependent upon the size and other factors. 

MUCOCILIARY ELEVATOR

The mucociliary elevator is an internal mechanism within the respiratory tract, that acts as a protection barrier from foreign invaders. The thick sticky mucous lining traps pathogens and other particles inhaled and the cilia move in a rhythmic fashion to expel the contaminates out of the body. This process is constant and involuntary. Cilia projections are continuously moving and beating. 

RESTRICTIVE VERSUS OBSTRUCTIVE LUNG IMPAIRMENT

Restrictive impairment within the lungs refers to a reduction with the air volume. It influences how much air can be inhaled and exhaled. An example of this could be hardening of the muscles surrounding the outside of the lungs that become rigid and less flexible. Obstructive lung impairment however, involved the small airways (or bronchioles) and damage to those entry ways. The lung volume (vital capacity) itself has not been altered, it is the airways that are obstructed or impaired. A very common example of this is individuals who suffer from asthma. 

In many of the pictures depicted above, there are example of military personnel or Veteran Affairs initiatives involved open burn pits and airborne hazards. This is just one major example in our society where men and women each day have risked their lives and continue to, in harsh, dangerous, and lethal environmental conditions. Often times, we advocate for some of the major hurdles in our paths that are often the one's seen. However, airborne hazards are usually invisible and taken for granted daily and they may in turn, be the most deadly. 

Toxicology: Everything and Anything Can Be Toxic

Most of time, we can quickly think about things that are harmful or dangerous to our health. Common items such as poison, chemicals, radiation, or even a toxic relationship and people. We can illustrate toxicity within all aspects of our lives. But when we think of water, food, or other natural sources that we need for survival, how can those things be toxic? Let's find out! 

WHAT IS TOXICOLOGY?

CSI or Forensic Files images often run through our minds when we think toxicology. Toxicology is a broad range area of science that analyzes nature, and adverse effects of chemical substances on living organisms. Additionally, toxicology studies detection of poisons and may be associated with the autopsy process in the event of a homicide or overdose (e.g., which is often the prime example illustrated in CSI). In the event that a substance has caused harm to a living organism, toxicologists and other health professionals, first want to find out how the individual was exposed, and how it entered the body. 

ROUTES OF ENTRY INTO THE BODY

Below are the most common routes of entry (i.e. occupational) into the body that cause toxic exposure:

• Inhalation
• Absorption
• Ingestion
• Injection (aka "sharps" needles, contamination with bodily fluids, etc)

BIOTRANSFORMATION PHASE I & II

Biotransformation is a fancy word for the alteration process of a chemical or drug within the body. This process is split up into two categories: the metabolism phase (I), and the conjugation phase (II).

Phase I is the addition or exposure of a chemical to functional groups and begins the metabolism phase. Three main chemical reactions can occur here: 1) hydrolysis, 2) oxidation, and 3) reduction. 

Phase II is where detoxification occurs within the body. 

So, we've talked about predominantly chemicals and substances that are clearly harmful to a living organism, regardless of the amount or frequency of exposure. So, then, how can we claim that everything can be toxic, including substances us humans are made up of? We are about to find out! 

WHAT IS DOSE-RESPONSE?

Does-Response refers to the relationship of exposure degree and the magnitude of the effect. The degree of exposure is the dose and the effect magnitude is the response. This is often illustrated in mortality percentage rate. You van view mortality rates for the United States here. 

I've been referring the the element of water. For example, if a person is submerged under a large body of water, then they will be exposed to a large dose amount of that element. Therefore, if unable to breathe in oxygen for a period of time, the response will be the individual will drown. That is an example of how water is toxic to a living organism. 

WHAT IS LD(50)?

LD50 is a benchmark used in toxicology. This refers to the dose of a chemical needed to produce death in 50% of the population given. This factor helps determine if action is needed within a population or area that may have a severe medical emergency or exposure.

WHAT FACTORS INFLUENCE TOXICOLOGY?

So, all in all, we may be wondering by now: so why should I care? While many of us may not come into direct contact with a clearly toxic chemical on a daily basis, we all do have many things in common. We are all breathing beings. We inhale and exhale every second of the day and whatever is in our environment, we are exposed to and potentially at risk for. Additionally, we all use products that are needed for hygiene and other necessities (i.e., paper products, toothpaste, hand soap, detergent, etc.). These products as well are in fact toxic. 

Some factors that influence toxicology are: 

• Concentration
• Route of entry
• Acute versus Chronic exposure (e.g., duration and frequency time)
• Environmental factors
• Chemical combinations
• Intraspecies variations
• Interspecies differences (e.g., dogs versus cats)

We are all impacted by toxic substances every day. The more we know and can educate ourselves and the community around us the healthier we can be!