Indoor Air Quality

Indoor Environmental/Air Quality

Introduction

As many as 30 percent of buildings in the United States have poor indoor air quality.
Source: US EPA

Health and buildings, increased air tightness and old rules for ventilation rates, indoor air 3-4 times more polluted (http://www.its-canada.com/reed/iaq/overview.htm), Sick building syndrome, overall increase in chemicals in environment, 60,000 more chemicals in use today as compared to 40 years ago, Health problems such as allergies, respiratory ailments and chemical reactions are all on the rise. In Canada 25% of the population has an allergy or chemical sensitivity, 10% of the adults and 20% of the children have asthma.

Key Word(s)
indoor air quality, IAQ, indoor environmental quality, IEQ, SBS, MCS, chemicals, VOC

Details

Employ an integrated approach. Involve building owners, entire design team, operators, maintenance staff, and tenants in the process.

Practice “prudent avoidance”. Avoid materials and components that may contribute to the problem. Choose increased ventilation. Steer clear before problems appear.

Evaluate the costs and benefits of all strategies. Compare life cycle costs versus the potential health consequences of occupants, decrease in guest satisfaction/worker production, and other economic and health consequences.

Checklist

  • Become educated on the issues of poor indoor environmental quality.
  • Assess the indoor environmental quality of existing buildings by surveying environments, employees, and clients.
  • Develop a plan to improve environmental quality of interior spaces.

Indoor Environmental Quality: Thermal Comfort

…is there an empirical study that shows the productivity pay-back for keeping workers in their prime temperature range?

There are at least 50 or so studies that directly bear on the question, and probably twice as many more orbiting this issue.

Bottom line is that there are strong asymmetric payoffs on the order of roughly -10:1 in terms of avoiding thermal discomfort vs improving thermal comfort. In other words, when thermal comfort drops, particularly from heat stress, look for productivity and/or performance (these are different concepts and measured differently) to drop ten times as fast as it shows improvement as people become more comfortable (thermally).

So, the first lesson is to avoid occupant thermal discomfort.

The second lesson is that thermal comfort is alot more than DBT in a space. The radiant temperature profile of a room around an occupant accounts for up to 60% of thermal discomfort in some situations. Non-thermal variables also effect thermal comfort. Occupant perceptions of control over ameliorative
actions and even the interior decor of a space has been shown to significantly affect thermal comfort, with the latter being worth about 1.5 deg F in the lab situations where it has been studied.

Overall, if you separate out the productivity effects and the human health effects of interior thermal conditions, you find roughly a range of -50% to +3% for productivity effects of thermal (dis)comfort and improved comfort in the research literature. Health effects run from a similar -50% to +10%.