We spend 90% of our lives in buildings. We spend 27 years of our lives in bed! As a result, most of the chemicals that we inhale are from indoor air. Indoor air has more chemicals than outdoors.
The concentrations for most chemicals indoors are higher indoors than outdoors. This is due to 1) emissions from building products, people, cleaning agents, cooking, and consumer products (toys) and 2) chemical reactions indoors.
We inhale more air mass per day then we drink water mass. Hence, we tend to inhale more unintentional chemicals per day than we drink.
We care about what goes into our students’ bodies. We require a permission slip for our students to use sunscreen and or take medicine. Hence, we care how chemicals get to our students’ skin and mouth. We should also be concerned with chemicals that get to our students lungs.
Kids. Kids stink. Due to hygiene issues, breath, smelly clothing and even skin oils kids emit chemicals into the indoor environment. This can lead to an unpleasant and potentially unhealthy classroom. Kids and teachers can also emit viruses in breathe and speech.
Building products. You know the new carpet smell or new vinyl floor smell? Those are chemicals you are smelling. Can they impact your health? It depends on the chemical and concentration.
Moisture. Mold needs three things to grow. Spores, food, and water. Mold spores are everywhere. Mold food is everywhere (including the paper wrapping on wallboard). The only thing the limits mold growth is moisture.
Cleaning Products. Cleaning products are needed to keep biological issues at bay in a classroom. However, products that are sprayed or wiped eventually evaporate into the air that teachers and students breathe. Balancing the need to keep a biologically healthy classroom with a chemically healthy is classroom is not an easy task.
Intentional Chemical Releases. “Air fresheners” (plug in or not), incense and diffusers sole purpose is to put chemicals into the air. These intentionally released chemicals do not remove offending odors, rather they mask foul smells.
Green does NOT equal healthy. Green product labels signify they are better for the environment than normal products. Better in this case means less environmental impact during manufacture, distribution or disposal. It does NOT mean the product is healthier for the user.
Essential oils are just chemicals. Many essential oils may be plant based chemicals, but they are still chemicals. Many of these chemicals are reactive indoors.
Chemical reactions are happening everywhere indoors. Ozone penetrates schools from the outdoor air. Unlike most chemicals indoor air ozone concentrations are about 1/3 the outdoor air ozone concentration. This is because ozone reacts with most things indoors: walls, desks, clothes, skin, and chemicals in the air (intentionally released or not). Once ozone reacts with a chemical it initiates a “Christmas tree” of chain reactions. The result of just one initial ozone reaction can result in hundreds of chemicals and particles forming. Some of the resulting chemicals can be eye and throat irritants. Other by products, like formaldehyde, can be carcinogens. Particles can aggravate bronchitis, cause asthma attacks, and increase susceptibility to respiratory infections. Recent research has shown particles can enter the bloodstream from the lungs and even cross the blood/brain barrier and the placenta. Younger lungs are potentially more susceptible to effects of these chemicals and particles.
Scenting agents and essential oils are some of the most reactive chemicals.. The pine, orange eucalyptus, and lavender smells all are typically generated by chemicals that are highly reactive with ozone. Intentionally increasing the concentration of these chemicals in a classroom will result in more of the irritating byproducts and particles, potentially creating a less healthy learning environment.
Chemicals are always present in indoor air. Even if you are not intentionally releasing chemicals into the indoor air, there are numerous other sources: cleaning products, building products and most importantly kids. Ozone reacts with skin oils initiating another cascade of reactions releasing more chemicals into the indoor air.
Remove sources. If the problem never enters the classroom then it won’t impact the indoor air. Sorry, you still have to let the kids in.
We can limit the chemicals we bring into the classroom. Don’t intentional release chemicals into the indoor air! Don’t use infusers, diffusers, plug-in freshers. Minimize the use of scented personal care products. If your kids use them, do a lesson on indoor air quality and ask them to use less scent products for the health of their peers.
Use only the minimum amount of cleaning agents required to keep a biologically healthy classroom. The highest concentrations of cleaning agents in the air will be during and immediately after cleaning. Clean at the end of the day after the last student has left the classroom and allow the room to ventilate overnight prior to using the classroom again.
Increase ventilation. If an odor problem exists in the classroom don’t try to mask it. Remove it. Odors can be indicative of inadequate ventilation. There are standard rates at which all classrooms should be supplied with outdoor air to minimize odor issues.
In MOST cases ventilating with outdoor air will lower indoor air concentrations (note this may not be the case for schools next to busy highways) and improve indoor air quality
This will require commitment of the facility management. Bringing in more fresh air requires more energy to condition that air. But the improved health, fewer sick days and more attentive students should make up for added cost.
Control moisture. Mold requires water to grow.
Keep the relative humidity between 40% to 60% (you can buy a relative humidity meter for less than $15). Above 60% there is enough moisture to allow mold to grow on certain surfaces. Below 40% can cause discomfort for those in the classroom. You can even use relative humidity measurements as a learning tool. Why is it different today than yesterday? Why is it higher indoors than outdoors? Why is it higher in the afternoon than the morning (or opposite)?
Look for locations with low airflow or condensation. Even in a classroom with good average relative humidity, condensation can occur on windows or cold pipes leading to mold growth on surrounding materials. Avoid creating areas with low airflow (behind bookshelves).
Keep an eye out for leaks in your classroom and address them immediately. A small stain can indicate much bigger hidden or future problem. Water damage can quickly lead to mold.
Institute control measures. Control measures should be the last resort after all other options have been exhausted.
There are many portable air cleaning devices that claim to clean indoor air from particle filters, to plasma generators, to ultraviolet disinfectors. Most claims other than particle removal are not backed up by science or produce a cascade of reactions similar to ozone.
Chemical removal on the classroom scale (not building wide) is generally either poor or not persistent (requiring frequent replacement of things like activated carbon filters). If chemicals or odors are an issue controlling the sources is a better option.
Particles, viruses and spores can be effectively removed by portable HEPA-only cleaners. Portable air cleaners with higher CADR (Clean Air Delivery Rates) will remove particles from a classroom faster. They will also use the most energy. If trying to remove viruses, look at the smoke CADR value. For typical sized classrooms a CADR of 300 cfm or above is ideal. In a typical size classroom with typical ventilation rates a portable air cleaning device operating at a CADR of 300 cfm will reduce particle concentrations relevant to viruses by 10 % to 40 %.
Always run HEPA portable air cleaning at the highest setting. If the noise is too great, try using two filters at half speed. Locate filters elevated in the middle of the room, paying attention to not create a tripping hazard with the cord.
If you are trying to remove a source that is associated with people (like a virus) run the portable air cleaner during the daytime. Most of the virus laden particles will be removed by the building HVAC system during the night if the HVAC is operated during the night. If you are trying to remove a source not associated with building occupants (like outdoor particles) run the portable air cleaner when not present in the classroom.
Portable air cleaners require replacement of filters. When viruses maybe present, make sure to handle dirty filters with care. Consider wearing an N95 mask and gloves and dispose the fitlers in sealed plastic bags.
Home is where the heart is. Hopefully you have been convinced to make air quality improvements to your classroom. If you are motivated to improve the indoor air quality where you spend over half of your life, there are many options.
Reduce sources. Increase Ventilation. Control Moisture. Institute Control Measures. The same principles apply to your house as your classroom.
Reduce sources. This is the easiest thing to alter. Determine if you need your laundry, dishes and hair to smell. Do you need an air freshener or diffsuer? Remember the smells are chemicals that you and your family are breathing. Whether the smell brings you more perceived psychological benefits than the potential negative health impacts is a personal decision we all have to make for our home. Think about the materials you use if you renovate. Do they smell? Even if they don’t they may emit chemicals into the indoor air.
Increase ventilation. New homes have ventilation systems. If you have one, make sure it is turned on and running at an adequate rate. However, make sure to turn if off during forest fires! Don’t seal up your house for energy efficiency concerns without considering ventilation.
Control moisture. Look for leaks and wet window sills.
Institute control measures. Operate HEPA filters in bedrooms. This is where you spend 1/3 of your life. Change the filters as recommended.
Avoid indoor air quality advice from commercial enterprises. If the webpage is trying to sell something (essential oils, an indoor air filter, sensor device, etc.) be wary. This site was created for educational purposes only. There are no links, advertisements or other revenue generation associated with this site.
You are responsible for your indoor air quality (to a point). You are responsible for many of the chemicals you breath. Using cleaning agents judiciously, cook on the back burner with the hood on, wear personal care products that are not scented. If you rent, before you sign your lease think about if the kitchen hood exhausts outside or if there are any moisture/mold issues. If you own, think about the impact of the building materials you use. More information my come if I get enough interst in this website.
