The Toxicology Behind Being Green

The green initiative is about understanding the chemical world we live in and educating customers about the sources and effect of chemicals found in their homes and in the air they breathe.

Green is in, and an increasing number of individuals, families, companies, and cities are adopting their own version of green living initiatives. These initiatives range from shopping with cloth bags on the consumer side, to certified Leadership in Energy and Environmental Design (LEED®) building practices on the professional side.

For HVAC contractors, the most visible green initiative is related to setting high environmental standards and goals and living up to them, at the global, national, state, community, family and business levels. From recylng packing materials, to monitoring how long a technician leaves a service van idling, to improving the indoor air quality (IAQ) of a customer's home, or following the ASHRAE 62.2,Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings guidelines, we need to take action. The quality of outdoor and interior air can ultimately effect your health and that of your customers.

The issue isn't that there are chemical contaminants in the air we breathe. We know they exist. The real issue is how toxic and how harmful those contaminants can become, and what solutions we can offer homeowners.

The green initiative is about understanding the chemical world we live in and educating customers about the sources and effect of chemicals found in their homes and the air they breathe.

It's a Chemical World Out There

National Geographic magazine has reported that hundreds of chemicals can be found in our bodies, some of which may remain for many years.(1). Toxicology (the study of poisons) has found that many of these chemicals are potentially harmful to human health. Simply put, our health isn't affected if we're not exposed to the chemicals. On a daily basis all of us are likely to be exposed to numerous chemicals, but it's the dosage that makes the difference. Exposure can either be acute or chronic, and can occur through air, food, or water. Exposure by air represents the most common contact for most individuals.

A major concept in toxicology is that “the dose makes the poison.” Anything can be hazardous to human health if a person receives a large enough, acute dose(2). While some chemicals are extremely toxic even at a low dose acute exposure, the concern for HVAC contractors and their customers is what happens with low dose chronic exposures of chemicals that aren't so acutely toxic.

That's where detection comes in. Low-level cabon monoxide detectors and IAQ analyzers capable of measuring the amount of toxics in homes is critical for the health of the customer and your company's profitability.

Factors that Affect Response

An interesting question that arises in toxicology is, why do different individuals exhibit different responses — or susceptibilities — to the same exposure? Apparently, much of our response is determined by our genetics. Genetics can determine how our bodies handle chemicals and how it repairs damage done by chemicals.

Age is another critical determinant of susceptibility. Exposing a developing baby in the womb to certain chemicals (for example, lead), can result in a miscarriage, or altered organ or brain development and function. Altered gene expression during early development or infancy may even result in the manifestation of diseases later in life.

Older persons are more susceptible to chemicals, as the body's ability to handle chemicals declines with aging.

The presence of an underlying health condition is another important contributing factor determining how an individual will respond to a chemical or biological agent in the environment. For example, an individual whose immune system is suppressed is much more susceptible to bacteria or mold exposures than a person whose immune system isn't compromised. An individual with an underlying pulmonary condition, such as asthma, will respond to a much lower concentration of irritant gases than a non-asthmatic individual.

Asthma is a chronic inflammation of the lungs and passageways following sensitization to antigens. Proteins from dust mites, cockroaches and rodent droppings can all serve as antigens. Exposure to irritants or asthma triggers a reaction in sensitive individuals, causing airway constriction and difficulty in breathing.

What's In Our Air?

More than ever before, the public is aware of the potential impact of chemicals in their lives. They want to know what's in their food, clothing, water, and air, and whether their health or the health of their children will be affected.

When people think of chemicals in the air, they usually think of outdoor pollution. But, according to the American Lung Association's 2007 “State of the Air” report, 96.7% of North American homes have at least one of six common indoor air quality problems.

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The EPA divides air pollutants into two categories: criteria pollutants and hazardous air pollutants (HAPs). Criteria pollutants are those for which a toxicological health-based regulatory criteria can be set to protect the most susceptible in our population. These include: carbon monoxide, lead, nitrogen dioxide, ozone,sulfur dioxide, and particulate matter. Most affect the respiratory system. Particulate matter worsens asthma and allergic attacks and can trigger heart attacks and strokes, leading to death. EPA classifies 188 chemicals as HAPs. They're referred to as hazardous because their toxicities are much more varied, and many have the ability to cause cancer, such as benzene, and vinyl chloride. Many of the HAPs are volatile organic compounds (VOCs) and when inhaled have the ability to distribute throughout the body causing damage to the cardiovascular, immune, neurological, and reproductive systems. HAPs are regulated principally through setting emission standards for their particular source.

Some criteria pollutants and HAPs are also present in indoor environments. Over the years it's become apparent that everyday exposure to potentially toxic pollutants occurs more often indoors than outdoors(3). Most individuals spend 80 to 90% of their time indoors. This is especially true for very young children, the elderly and those chronically ill. The indoor environment contains materials and surfaces that can act as emitters and reservoirs of pollutants. Finally, concentrations of pollutants can be several times higher in indoor air than in outdoor air.

The modern indoor environment contains a variety of sources of VOCs, including building materials and consumer products. One component of LEED® certification is based on the use of materials, such as paints, that have reduced VOCs. Environmental tobacco smoke (ETS) is a major source of irritants, toxic chemicals and carcinogens, such as benzene. Poorly ventilated gas stoves are a source of nitrogen dioxide, a respiratory irritant. There are also biological sources of indoors air pollutants such as such as mildew and molds.

The “State of the Air” report 2007 states that dust, dander, spores, bacteria, and other irritants appear in 91% of homes.

Marketing A Healthy Home Environment

Understanding that there are susceptible individuals allows you to identify customers who are at risk and need improvement in the Indoor Air Quality of their homes. Technical tools help determine the source and the amount of potentially toxic chemicals in the indoor air environment and professionally, ethically and visibly demonstrate to the customer whether to be concerned. Marketing tools educate the customer about the multiplicity of services and products available from your company to protect their health and the health of their families. Educate the technician on how to communicate the facts.

Show the the customer how these options can be made available in affordable, budgeted packages.

John LaPlant, along with his wife Vicki LaPlant, are co-owners of Vital Learning Experiences Enterprises (VLE Enterprises), Pottsboro, TX. VLE is a training and consulting business focused on the hvacr and plumbing industry. Visit or call 903/786-6262 for additional information.

Michael Trush, Ph.D., is deputy director, Johns Hopkins Center for Urban Environmental Health, Baltimore, MD. He can be reached by email at [email protected].


  1. David Ewing Duncan, “The Pollution Within,” National Geographic, 240:116-143,2006.
  2. Casarett and Doull's “Toxicology; The Basic Science of Poisons,” 6th edition (C.D. Klassen, ed.), McGraw Hill, 2001.
  3. Wayne R. Ott and John W. Roberts, “Everyday Exposures to Toxic Pollutants,” Scientific American, 278:86-91,1998.

Be an Information Source

  • Develop marketing tools to educate customers about the toxic chemicals in their home and the negative health effect of these chemicals to babies developing in the mother's womb, children, and the elderly.

  • Have technicians provide a fact sheet to the customer. The fact sheet can contain references about toxic chemicals found in homes and solutions your company can provide to dilute or remove toxic chemicals.

  • Add a section on your website about toxic agents, with links to third party websites such as the Environmental Protection Agency (EPA). Let the neutral third party provide the information so that you never appear to be using a scare tactic.

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