Tag: thermal comfort

We continue our discussion on human body systems and the work environment with a focus on Air. We will pay special attention to the air as sensed and felt by human beings, and to how building occupants’ actions influence the quality of the air they breathe.

Let us start again with a snapshot of my (Yoko’s) experience of air.

I (Yoko) had a mask on at the client meeting in the morning in early March 2021. I felt my own breath and voice bouncing back to my mouth. It was hard to communicate. Back at home, I am in my heated home office, mask-less. The temperature inside is comfortable, but my toes still feel chilly. I also yearn for the freshness of exterior air. I do not feel any hot air blowing in my face, but still, my eyes, nose, and throat are dry.

The state of indoor air is often evaluated in two different measures.

• Indoor Air Quality (IAQ)
• Thermal Comfort (TC)

These names are confusing for most of us, since the former seems to include the latter (it does not, although it is related to it) and the latter seems to be a luxury, not critical and essential as it really is. 

Human Factors in IAQ

Building occupants can improve or deteriorate IAQ and TC.

IAQ refers to the air quality in/around buildings as it relates to the health and comfort of occupants. It is evaluated by the amount of harmful substances including bacteria, mold, dust, CO, CO₂, fibers, and particles. (Yoko needed fresh air, most likely because some of these were present in her office.) Polluted or low-quality indoor air and the poor ventilation that contributes to it causes sick building syndrome¹Wargocki P, Wyon DP, Sundell J, Clausen G, Fanger PO. The effects of outdoor air supply rate in an office on perceived air quality, sick building syndrome (SBS) symptoms and productivity. Indoor Air. 2000;10(4):222-236., and are linked to cancer and respiratory health issues including death.²Jacobs DE, Kelly T, Sobolewski J. Linking public health, housing, and indoor environmental policy: Successes and challenges at local and federal agencies in the United States. Environ Health Perspect. 2007;115(6):976-982. doi:10.1289/ehp.8990

Building occupants are not only sufferers here but also one of the causes. They are one of the four major elements involved in IAQ issues, along with the HVAC systems, pollutant sources, and pollutant pathways. They are so due to their personal activities (smoking or cooking), their housekeeping habits (types of cleaning materials or vacuuming), and the method and frequency of maintenance activities.³United States Environmental Protection Agency. Building Air Quality Guide: a Guide for Building Owners and Facility Managers, 1991. https://www.epa.gov/indoor-air-quality-iaq/building-air-quality-guide-guide-building-owners-and-facility-managers (accessed 7/16/21)

Human Factors in TC

TC is defined as “the condition of mind which expresses satisfaction with the surrounding environment of the occupants”⁴ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers). Comfortable thermal conditions of the air (breathed and sensed by occupants) are essential, not a luxury.  Cold indoor temperatures are associated with increased blood pressure, asthma symptoms, and poor mental health.⁵Wilkinson P, Landon M, Armstrong B, Stevenson S, McKee M. Cold comfort: the social and environmental determinants of excess winter death in England, 1986-1996. York: Joseph Rowntree Foundation; 2001. High indoor temperatures are linked to higher rates of emergency hospitalizations and deaths.⁶Benmarhnia T, Deguen S, Kaufman JS, Smargiassi A. Review Article: Vulnerability to Heat-related Mortality: A Systematic Review, Meta-analysis, and Meta-regression Analysis. Epidemiology. 2015;26(6):781-793.

To determine the comfortable air for occupants, tools such as the psychrometric chart based on ASHRAE-55 is used. People’s metabolic rates based on their activities (writing or lifting packages) and clothing (shorts or long-sleeved shirts) are considered and balanced with air temperature, speed, and relative humidity. Again, people are not only sensors and sufferers, but also have means to control TC.

How to Create Good IAQ and TC Environments

In workplaces, poor IAQ and TC hurt business. Poor air quality is found to increase the rates of absences⁷Chan WR, Parthasarathy S, Fisk WJ, Mckone TE. Estimated effect of ventilation and filtration on chronic health risks in U.S. offices, schools, and retail stores. Indoor Air. 2016;26(2):331-343. doi:10.1111/ina.12189 and decrease employee productivity up to ten percent (10%).⁸Wargocki P, Wyon DP, Fanger PO. Productivity is affected by the air quality in offices. Proceedings of Healthy Buildings 2000. 2000;1:635-640. High air temperature and high humidity also increase absenteeism, cause poorer performance and lower employee morale.⁹Vimalanathan K, Ramesh Babu T. The effect of indoor office environment on the work performance, health and well-being of office workers. J Environ Health Sci Eng. 2014;12:113-113. How can we improve the indoor air around us for our well-being and productivity?

Steps to be Taken with Human Behaviors in Mind

Now that we understand that we, building occupants, can be a part of air problems, any approach taken needs to take into consideration human behaviors as well as various technological ones. Please take a look at our previous articles on sound(Part1 & Part2) for more details where we discussed a similar approach because people suffer from noise but also contribute to making noise.

1. Education: Form an understanding of how humans affect the air and the individual differences when it comes to a sense of comfort.  Also, discuss clothing as a possible tool that impacts comfort levels.
2. Protocols: Establish protocols to:
   • Avoid personal activities that harm the air (no smoking),
   • Take actions to improve the air (open windows, use air purifier),
   • Follow housekeeping and maintenance requirements, and
   • Adhere to specified air “zones”(see 4).
3. Surveys: Survey occupants to find existing issues and their relationship to different activities/behaviors and personal preferences. Perform engineering surveys to measure air issues and their relationship to the spatial layout.
4. Spatial layout/design and engineering: Create spatial and engineering zones according to IAQ and TC requirements for different activities and populations. Use building materials that do not negatively affect air quality.
5. Maintenance:  Monitor conditions continually to ensure the planned and specified environment is kept.

There are newer technologies that allow us to monitor and detect changes in more defined and personalized ways. There are non-contact temperature assessment devices, such as thermal imaging and non-contact infrared thermometers, and also portable individual comfort systems which we will discuss in more detail in our upcoming “Monitoring humans and the environment” article.

How We Breathe

So far, we discussed how human beings create and maintain better air environments. Now, let’s take a look at “how can we breathe this “better air” better?”

One way is to be in good posture. Bad sitting posture, such as leaning forward with our heads down while working on computers, affects our breathing pattern and may lead to breathing dysfunction. ¹⁰Zafar, Hamayun et al. “Effect of Different Head-Neck Postures on the Respiratory Function in Healthy Males.” BioMed research international vol. 2018 4518269. 12 Jul. 2018 By using the methods we introduced in our “Kinesthesis and Work Environment” articles (Part1 & Part2), we can maintain good posture which will help us breathe better.

Another is to meditate regularly with our breath as a primary “object” (being with it without controlling it, and keep coming back to it when distracted.) This will make us aware how we usually breathe and help us find how to breathe more deeply. It comes with the bonus of reminding us how our body is a part of space (link here) and decreases stress and anxiety.

We could also just move our body to breathe better. Try to walk more in the office or at home with some help from furniture and spatial design. Walk to get some water or to open a window. Also, stretching exercises periodically can relieve the tightness of our shoulders, chest, and back which will help us breathe better just as a good posture does. Spatial zones where you can go to stretch or do some yoga are advantageous to better breathing as well.

Building occupants can improve or deteriorate Indoor Air Quality and Thermal Comfort.

Y. Kawai & Y. Burton

Olfactory Comfort

When we breathe air, we are also smelling it. We often judge air quality by its odor and alarm ourselves when it is unfamiliar or unpleasant.¹¹Dalton, Pamera. There’s Something in the Air: Effects of Beliefs and Expectations on Response to Environmental Odors. In ucco, G. M., Herz, R. S., & Schaal, B. (Eds.). (2012). Olfactory cognition : From perception and memory to environmental odours and neuroscience. Pp.23-38 Odors are more than just a signal. Inhalation of an odorant, such as odorous volatile chemicals, can directly affect our organs.¹²Jirovitz, J., Buchbauer, G., Jager, W., Woiiieh, A., & Nikiforov, A. (1992). Analysis of fragrance compounds in blood samples of mice by gas chromatography, mass spectrometry, GC/FTIR and GC/AES after inhalation of sandalwood oil. Biomedical Chromatography, 6, 133–134. One of the ways to decrease this risk is to avoid using materials that include volatile compounds in furniture, floors, walls, or paint. There is also some evidence of fragrance products (perfumes) negatively affecting the body.¹³Caress, S. M. & Steinemann, A. C. (2009). Prevalence of fragrance sensitivity in the American population. Journal of Environmental Health, 71, 46–50. We recommend including the discussion of fragrance usage when creating the protocols mentioned above.

Certain fragrances can have beneficial effects on our physical and mental well-being.¹⁴Stoddard, M. (1990). The scented ape: The biology and culture of human odor. Cambridge: Cambridge University Press. Even under a high atmospheric pressure environment, aroma from plants improves automatic nerve reflex and precapillary circulation of cerebral blood flow.¹⁵Koura et al. (2012) Proceeding of Annual Global Healthcare conference Placing indoor plants with a pleasant aroma nearby achieves that as well as the benefit of visual exposure to nature. Some companies also produce air conditioners and purifiers that diffuse aroma.

IAQ and TC are Important for Our Wellbeing

Humans not only suffer from air quality issues but are also contributing to them. Therefore any steps that are taken to control the quality of air must always take into account the actions for and by humans. Learning how to breathe better is also important in order to get maximum benefit from the good quality air we create.

In our next article, we will continue our discussion with a focus on Light.

(Written by Yoko Kawai and Yvonne Burton)