Nuno Canha, PhD – University of Lisbon – IAQ and Ventilation During Sleep

After finishing his master’s degree in chemistry, Nuno Canha was thinking about what to research when he learned about a research project to study IAQ in primary schools in Lisbon, Portugal. As a research project assistant,he became interested in IAQ. His interest in IAQ and sleep piqued when he attended an IAQ Conference in Hong Kong and the future of IAQ was discussed.

Nuggets mined from today’s episode:

Schools in Portugal are built with masonry construction.

Schools in Portugal utilize natural ventilation. Windows are closed during the winter and open in spring and summer. Portuguese schools do not have air conditioning. Some schools were remodeled and forced air ventilation installed, the equipped proved too costly to maintain. Schools in urban areas have maintenance challenges due to maintenance workers being spread thin. Schools in rural areas are better maintained. The schools that were studied were 10-30 years old.

The majority of common folk in Portugal are unaware of IAQ issues.

Portugal was an early adopter of IAQ legislation. In 2006 an Energy Certification of large buildings was instituted in Portugal of which IAQ guidelines was a component of the certification. A building audit was performed by auditors trained in IAQ inspection and energy efficiency. Should a building be out of compliance, corrective measures were taken and a second audit was required.

Several labs in Portugal perform IAQ inspections.

Portugal generally has acceptable PM 2.5 levels. Most of the monitoring stations are located within urban areas. Traffic is the main source of PM 2.5. Acceptable levels are exceeded in urban areas during high commuter traffic.

The indoor CO2 limit in Portugal is 1150 PPM.

A change in the law in 2013 made compliance voluntary. The guidelines are referenced when there is a complaint or a suspicion of an IAQ problem exists. Dr. Canha, opined that this is a drawback

The study

We spend 1/3 of our lives sleeping. Sleeping in poorly ventilated areas increases our exposure to CO2 which lowers next day performance.  Flame retardants, isocyanates, phthalates, formaldehyde, residual detergents, dust mite fragments and feces, from bedding and pillows are emitted in our breathing zones while we sleep.

A preliminary study in bedrooms was done assessing: temperature, RH, VOCs, formaldehyde, PM 2.5 & PM 10, and air changes per hour. The study was done in the summer. The buildings studied were of masonry construction with electric heat. The floors in bedrooms were wood, no carpeting.

4 different scenarios were studied: windows and doors open, windows and doors closed, windows open doors closed, doors closed and windows open. The study was done over 3 nights. During the study, ventilation rates varied from 0.7 air changes per hour in closed rooms to 5 air changes per hour in open rooms. Monitoring equipment was placed in the middle of the room, approximately 3 feet from the bed to minimize noise.

Real time monitoring was done with: Graywolf® (temperature, RH, CO2, VOCs), formaldehyde meter, DUSTTRAK® particle counter

Conclusions from the study:

Sleeping environments are usually characterized by low air change rates and, as this preliminary study showed, some indoor pollutants, such as VOCs, formaldehyde and PM2.5, may reach concentrations above the established guidelines. Improving natural ventilation, by opening doors and windows, may increase air change rates but, simultaneously, the infiltration of specific pollutants from sources other than the ones in the bedroom, such as from outdoors or from other spaces of the house (e.g. kitchen).

Improving awareness of IAQ in kids

Dr. Canha is working in an European project (called “LIFE Index-Air”) which ultimately aims to reduce PM 2.5 exposure. Within the scope of LIFE Index-Air, he has been involved in awareness campaigns (called “The air belongs to everyone”) at Lisbon (Portugal) primary schools about air quality (including IAQ at homes and classrooms) dedicated for young children (6-9 years old). The main aims of this awareness campaigns are to show to the kids about the importance of a good air quality, pollution sources, exposure routes and how to improve IAQ. The kids are learning to connect the dots and understand the significance of IAQ. Until now, 4,000 kids have attended more than 50 awareness campaigns since March 2017.

More info can be found at their webpage or facebook page:

Ongoing research

How does IAQ may affect sleep quality?  What is the relationship between sleep, occupant welfare and next day performance? He is working in conjunction with sleep doctors and cardio respiratory experts. They are studying couples over a10 day period. In addition to IAQ parameters they are also measuring levels of activity by actigraphy during the entire monitoring period. Measuring bacteria and fungi levels before and after sleep. The sleep quality is also being studied using Polysomnography. They are trying to understand the specific air pollutants that effect sleep quality.

Final comments:

It’s important to talk about the air we breathe and its importance and we should consider always all microenvironments where we spend time, including the ones where we sleep.

Z-Man signing off

Trivia:

What is the common thread running between these three incidents: the 1989 Exxon Valdez oil spill off Alaska, the Challenger space shuttle disaster and the Chernobyl nuclear accident?

Answer:

All have been attributed to human error in which sleep-deprivation played a role.