I Can Feel Benzene Comin' In The Air Tonight, Oh Lord

Air quality is vital to a healthy environment, but it can be very hard to monitor and control. In many instances, airborne pollutants can be completely undetectable without appropriate equipment. In other instances it can be quite visible. Smog is a common occurrence in many large cities and can lead to various adverse health problems. Various levels of contaminants are permitted within the workplace and the standard set by OSHA determines how much is allowed. All of the various chemicals as well as the Occupational Exposure Limit are created by OSHA.

Thick Smog In Beijing - CNN.com

Air can be sampled and tested in various ways. Personal air sampling devices can monitor the air in ones breathing zone. The breathing zone is a radius of approximately 9-10 inches from the face. The OSHA standards for air quality vary from substance to substance. The Occupational Exposure Limit (OEL) for Benzene in the air is 1.0 ppm. The OEL is the standard set by OSHA. This is typically measured in parts per million, which is so fractionally small it is almost unfathomable.

A Personal Air Sampling Device

Air can be sampled via pump rotameters. In this case, a pump is connected to a tube and air is pulled into the tube. One calculates the flow rate by timing the solution rising up the pump. We calculated the flow rate and benzene levels for an 8 hour sample in class with the following results:

Q= The Flow Rate

500mL / 14.7 sec = Q

1000mL / 29.4 sec = Q

34.01 = Q

8 hour = 480 mins

480 min (2.041ppm) = 979.2 L*ml^3 / 1000 L

The final calculation was that the air contained 0.749 ppm Benzene, which is within the OSHA standards. 

The NIOSH method number for sampling Benzene is 1501. The method used is a sorbent tube containing coconut shell or charcoal. 10% of the sample should be blanks. The sample stability of benzene is less than four hours. This means that the sample must be sent to a lab within hours after being taken, which is a huge drawback for the person who is sampling.

An Image of Charcoal Sorbent Tubes

Sampling air and maintaining air quality creates safe and healthy environments for workers. The standards set by OSHA create a limit on the amount of a substance that can be in an environment before it becomes problematic to the employee. Many toxic substances aside from benzene can affect air quality. For example, in nail salons, workers are constantly breathing in harsh chemicals like acetone. The OSHA standard for acetone is 1000 ppm. Another potentially toxic substance is formaldehyde, which is very typical in lab settings as a preservative. The OSHA standard for formaldehyde is 0.75 ppm which, meaning that it is even more toxic than acetone. 

In a workplace, people are often put in situations where they may not be certain what they are inhaling. These standards and methods for controlling and monitoring are put in place to protect the health and well being of all workers.

(Please Don't) Take My Breath Away

Image of Cilia

The ease of breathing is something that most humans take for granted. The lungs consist of a complex system of spongy tissue, tubes, capillaries and alveoli. The lungs allow for diffusion of air into the bloodstream, so as you can imagine, when the lungs suffer any level of damage the body can really suffer. Air (as well as potential toxins) enter the body from the nasopharynx, through the trachea, to the bronchi, to the lungs. Within the lungs there are loads of capillaries and alveoli for air diffusion and cilia to keep out harmful toxins.

The cilia of the lungs create a mucus layer which transport dust and other particles along the outer part of the lung to prevent it from entering. In a healthy respiratory system, the properly functioning mucociliary elevator captures the things that do not belong within the lungs and helps them to exit the body.

Lung Damaged By Cigarette Smoke

NIOSH Microscopic Image of Silica Dust

There are a variety of chemicals that can be harmful when inhaled. They vary in size as well as potency. The smallest particles are gases. Many gases can be toxic when inhaled while others are harmless. Gases are often used in warfare, and people can come into contact with them in various jobs such as mining, or while working with toxic chemicals. Vapors and mists can also cause harm when inhaled. Dust is infamous for causing allergy flare ups and being very harmful for people with asthma, but it is actually something that is supposed to be monitored closely in the workplace. In high levels it can be pretty unhealthy. Construction workers are often exposed to silica dust, which causes permanent damage to the lungs. Smoke is also toxic when inhaled in excess.

There are two types of lung impairment that can occur when airborne hazards are inhaled. One type is restrictive. Restrictive lung impairment causes the volume of oxygen within the lung to decrease. This occurs when nasty particles are inhaled, such as black mold. Another type of lung impairment is obstructive impairment. This occurs in people with asthma or COPD and happens when the bronchiole is inflamed. COPD can occur when one is exposed long term to industrial dusts in the workplace.

Every Rose Has Its Thorn; Let's Talk About Poison!

Toxicology is defined as the study of the adverse affects of poison on the human body. So what exactly is a poison? A poison is something that can cause a living being harm in certain doses. Caffeine, salt and even water can all be toxic if the dose is high enough.

In order for us to study the way that poisons affect humans, the poison must first enter our bodies. The route of entry varies from substance to substance. Substances can be inhaled, absorbed through the skin, injected or ingested.  Many people have occupations which involve daily contact with poisons. Because of these types of jobs, we need people and machines to monitor this intake of toxic chemicals and the harm that is caused as a result. Occupational toxicology was created specifically to study and hopefully prevent contact with toxic substances in the workplace. Occupational toxicology is vital to creating a safe and healthy workplace for everyone.

Miners have some of the most dangerous jobs on the planet. Not only are they in constant danger at work, surrounded by intense equipment and dangerous positions within mines, but even years after they leave their jobs they're still at risk. The chemicals and compounds that they come in contact with have the potential to threaten their health long term. Sulpher miners in Indonesia risk their lives and lungs to feed their families.

As Paracelsus said, everything is a poison, so how is it that we can be constantly interacting with poisons without becoming ill? Some substances can pass through our bodies in small doses without affecting our bodies negatively. In this situation, our body's dose-response has not reached the threshold at which the substance becomes toxic. The dose-response is the relationship between the amount of a substance and the resulting response of the body. Asbestos is a commonly known material, famous for causing health issues when inhaled. It is common in old buildings in homes and is often an issue for people working in construction. People exposed to too high of a dose of asbestos can develop cancer, mesothelioma and asbestosis. As a result of the high level of toxicity of asbestos, it has become a priority to educate workers who have to be in contact with it, and to eliminate it from homes and work places altogether.

The scale used to measure the toxicity of a substance is called the LD50. The LD50 is the level of a dose of a substance it takes to kill 50% of animals the substance has been given to. Botulinum toxin has the highest level of LD50. The lower the number, the more toxic the chemical is. Botulinum has an LD50 of 0.00001 mg/kg. As a comparison, ethyl alcohol (booze) has an LD50 of 10,000 mg/kg.

So what chemicals did I find in my workplace?? Well to begin, I work at Printing Services. I typically make t-shirts, so I looked at some of the chemicals that we use in this process. About a year ago we got a product from Brother called Pretreat, which is used to treat shirts prior to printing on them. I looked for a list of ingredients but only found a label telling me that contact could give me inflammation (which has actually happened to me after accidental contact from a spill) and that ingestion may result in vomiting and diarrhea (which has not happened to me...YET). A quick google search taught me that the ingredients are: 45-75% water, 10-20% inorganic nitrate and 5-15% a "trade secret". That's a little concerning?

I also found a bottle of pretty common cleaner called Mr. Muscle and a Brother ink cartridge.

Mr. Muscle Cleaner

Top: Brother Pretreat Label
Middle: Pretreat Bottle
Bottom:Brother Pretreat Warning Label

Brother Ink Cartridge