A snake plant, pictured above, is one of the many plants that can naturally filter your air.  Near the end of this article there’s a link to six other plants that are also great air filters.

Making an indoor environment healthy for human occupants is not as simple as it seems.   There are fans, dampers, pressure sensors, thermostats, heating and cooling coils, filters, controls, and a fair bit of math to figure it all out.  Usually most the equipment is hidden from view, behind ceiling tiles and tucked away in mechanical rooms.  It is also extremely important.

Keeping people healthy, happy, and productive at work is critical for any organization; probably none more so than a hospital.  That equipment we spoke about has a big impact on indoor environmental quality and that has a major impact on people.  Well ‘duh’ you are probably saying to yourself.  But let’s put some numbers to it.  A recent study called “The Impact of Green Buildings on Cognitive Function” was a partnership between Harvard, Syracuse University Center of Excellence, and the SUNY Upstate Medical School.  They tested participants in a green building environment and in a conventional working environment by modifying the VOC levels and CO2 levels over the period of six days.  At the end of each day they tested  the participants by running them through a series of cognitive tests, which included things like crises response, strategy, and focused activity levels.   They found that people working in green building environments performed 61% to 101% better in those cognitive function tests.  Their findings aligns with others, identify productivity increases of 10% or 15% and reductions of absenteeism of 35%.  Those are big impacts and it’s something all buildings should strive for.


On average, cognitive scores were 61% higher on the Green building day and 101% higher on the two Green+ building days than on the Conventional building day


There is a challenge however.  Older buildings.

In older buildings meeting new standards or best practices can be difficult.  The older technology just didn’t have the same capabilities as today.  Imagine your cellphone from 15 years ago, if you can.  What capabilities did it have?  Perhaps it looked something like this:

Old Cell Phone

Oh the horror,

An old building’s HVAC (Heating Ventilation and Air Condition) system can be an interesting sight, just like looking at an old cellphone.  Some of them are like stepping into a steampunk alternate universe.  Control systems made up by loud compressors forcing air through the snaking pneumatic tubing, eventually pushing air bladders up and down to make valves and dampers move.  These old systems are not compatible with modern design requirements but they do represent opportunities to improve the indoor environmental quality and even save energy at the same time.

Renovations are an ongoing necessity at any hospital.  Most are buildings that will continue to be healtcare facilities for years to come and thus quality design is a good investment.  At UHN we look to make the best improvements possible in any renovation. I’ll have to save some of the details for another blog but I’ll go through some highlights.  Here are some of the things we look at for renovations and are included in UHN’s Energy and Environment Construction and Design Guidelines:

  • Increased ventilation and outdoor air – renovated spaces are designed to meet the new standards for ventilation.  For healthcare facilities that means following CSA Z317.2, and sometimes ASHRAE 62.1 , both of which are referenced in the building code. But higher ventilation rates can also mean higher energy costs, if systems aren’t designed properly.  There are good standards for energy savings, like ASHRAE 90.1 and ASHRAE 189, but in the end it’s thoughtful engineering design that makes for a functional, efficient HVAC system.
  • Filters with consistent filtration quality – Filters should have with a Minimum Efficiency Reporting Value (MERV) that follows ASHRAE 52.2 with Appendix J.  That means instead of Merv 8 filter, you get a Merv 8A filter.  The ‘A’ suffix is key.  It means you’ll get that rated filtration value for the life of the filter, not just for the first couple days it’s installed.
  • Products with low Volatile Organic Compounds (VOCs) – If you can smell it it’s probably a VOC, but some are more harmful than others (like those found in glues and paint).  The key here is to keep the toxic stuff out of your space.  Thankfully the industry has largely transitioned to lower VOC products, largely due to the LEED green building rating system and better overall awareness.
  • Outdoor air with heat recovery – High levels of outdoor air with energy offset through heat recovery wheels and heat recovery loops.
  • Demand control ventilation – for areas that are partially occupied we are installing occupancy sensors to provide high levels of air only when people are in the space.  Otherwise the mechanical system ramps down to a minimum level when the space in unoccupied.  PMCRT and KDT also have demand control ventilation on lab spaces, which actively sample for contaminants.  Mike Kurz wrote a great blog about this.
  • New Direct Digital Controls – replacing pneumatic control devices with electronic devices.
  • Installing LED lighting – to improve light levels, remove UV wavelengths, reduce flickering, and save energy.  In the past year alone over 15,000 LED lights have been installed at UHN (thanks Mike Kurz!).
  • LEED based Design – The Krembil Discovery Tower was recently awarded it’s LEED Silver designation and much of our construction and design guidelines for renovations mirror the LEED green building rating system.  The benefit of going through the full lead certification is the level of rigour and assurance that the targets have been met.

We are also piloting new technologies to assess their benefits:

  • Piloting advanced filtration technology – which imparts alternating charges on particles, causing them to clump together so they can be caught by the filters
  • Piloting indigo wavelength lighting – to destroy bacteria and viruses that attach themselves to particles in the air.


What about at Home?

To improve your indoor air quality at home there are a few things you can do:

  • Indoor plants can filter your air naturallyhere’s a list of plants that will remove indoor contaminants.
  • Keep toxins out of your home – the best way to eliminate contaminants is to prevent them.check any products or materials before installing them in your home (couches, carpet, paint, ).  Paints and adhesives should should be low in VOCs, flooring should be Floorscore certified, cleaning products should be Ecologo certified, wood products should have no added urea formaldehyde, furniture should have no added fire retardants.
  • Dust – you are breathing in small particles constantly, most are too small to see with your eye (unless the sun in shining in).  As materials break down or combustion gases make their way into your home.  The problem is that some of these small particles are damaging to human health, whether because they are toxic or because they are small enough to damage aveoli in your lungs.  Vacuum and dust to keep them out of your air.
  • Filtration – Change your air filter or install a small dedicated filter (I have this one from Rabbit Air and it can turn a room from stuffy to outdoor fresh.  I wouldn’t normally endorse something like this but I’m quite happy with it 1 year in).
  • Get outside –  We humans spend 90% of their time indoors, where pollutant levels can be two to five times higher.


If you have other suggestions or any specific questions please post it in the comments: