Chemical Engineers and Pandemics

Chemical Engineering: the art and science of creating and operating industrial scale systems for transforming raw materials into useful products.

Photo by Gustavo Fring on

When “chemical engineering” is mentioned, many people think of chemical plants, refineries, and such. That’s one part of it, but it also encompasses many other things, including pharmaceuticals and vaccine manufacture. These days, everyone is talking about and hoping for a vaccine for Covid-19. What does this mean for some chemical engineers and what they need to do?

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N95 Masks and Re-Use

Recent pandemic developments have strained the supply of N95 filtering facepiece respirators (FFRs), which protect users from particles and aerosols in the air that they breathe. Technically, they must filter out at least 95% of 0.3 micrometre particles.

Normally these are meant to be single-use devices, and are removed and disposed of in a secure way to prevent infection transmission. However, with supply shortages people are considering or resorting to re-using these FFRs, possibly with some sort of chemical or physical disinfection process. Disinfection processes are never 100% effective, so this is not a great option, but I guess it’s better than having no protection.

One disinfection method that I’m very familiar with is UV-C disinfection, having done research in the area of photochemical processes for several decades. There is published literature available demonstrating reasonable disinfection success for UV when applied to N95 FFRs, so this may be an approach to consider if necessary.

I’m working on an overview of this literature (draft version now available at this link), but I’m happy to consult (pro bono) with health care institutions that are considering UV applications to deal with their situations (


With the recent development of a viral pandemic, people are being reminded about the importance of handwashing for infection prevention. Coincidentally, in 2019 my colleague Prof. Marc Aucoin and I supervised a research study on handwashing for the CSA Group, a product standards organization. Specifically, our study aimed to determine if the faucet water flow rate had a significant effect on the ability of handwashing to remove bacteria from the skin.

You can access and read the full report on their website. The bottom line is that no, the water flow rate from the faucet didn’t have a significant effect over the range we tested, from 0.5 to 2.2 gallons per minute (about 2 to 8 litres per minute). Under all of those flow rates, on average about 99.3% of E. coli bacteria would be removed from the hands, which is good to know.

To do this study, we had to control all the other variables as much as possible, including the water temperature, and the amount and type of hand soap used by each person. The other big factor is the way that the hands were washed, including the length of time. For this study, we used a certain protocol from Public Health, and everyone involved in the study learned how to properly wash their hands. This was a good learning opportunity for people, including me, and so I reproduce the protocol that we used below. It’s a useful skill to know how to thoroughly wash your hands these days.

Recommended handwashing technique for infection prevention.

Enhanced Mobility Wheelchair wins first-place at the 2019 IDeA competition

A nice example of mechanical engineering students using their skills to solve real-world problems. See the link below for more details.

Five mechanical engineering students created the Enhanced Mobility Wheelchair for their 2019 capstone design project, and now their work is being nationally recognized for improving accessibility and inclusivity in Canada.

Wheelchair users often face challenges when deciding which device to use to get around. Regular wheelchairs are easy to manoeuvre, but hand-cycle wheelchairs offer better speed efficiency. The Enhanced Mobility Wheelchair team has designed and prototyped an augmented wheelchair that provides users with the comfort and maneuverability of a traditional wheelchair while offering the speed of a hand-cycle wheelchair. The novel drive system provides greater ergonomic support and promotes good posture even when the operator is tired. Selectable gear ratios greatly improve motion efficiency on a variety of terrain, helping those confined to a wheelchair go further and faster than ever before.

Source: Enhanced Mobility Wheelchair wins first-place at the 2019 IDeA competition | Waterloo Stories | University of Waterloo

U Waterloo #13 Worldwide!

The latest university ranking scheme is one from Times Higher Education (THE) and their University Impact Rankings for 2019.  This new ranking is based on the 17 UN Sustainable Development Goals and how well each university contributes towards meeting those goals. According to a news summary, Waterloo does particularly well on 4 of the goals, namely Partnership for the Goals, Sustainable Cities and Communities, Climate Action, and Reduced Inequalities.

Listing of the 17 Sustainable Development GoalsOverall, Canadian universities score well in these sustainability rankings, with McMaster #2, UBC tied for #3, University of Montreal tied for #7, York #26, and Toronto #31.  McGill comes in somewhere in the 101-200 range.  I haven’t spent any time looking at the details yet, so I’m not sure what contributes to some of these rankings.

A lot of the “top” US universities didn’t participate in these rankings, so it’s hard to make many comparisons.  The top 3 ranked US colleges in these rankings were U of North Carolina at Chapel Hill at #24, Arizona State at #35, and U Maryland Baltimore County at #62.  I’m aware of these places because they have strong STEM programs and research activities, but most Canadians probably aren’t aware of them.  Perhaps next year more US colleges will participate.

In general, sustainable development is an important goal and increasingly a part of engineering education and practice.  Engineers Canada, the body responsible for accreditation of engineering education in Canada (among other things), has a national guideline on sustainable development for professional engineers published in 2016.  Various bits and pieces of this are already built into our curriculum for chemical engineers (and I assume in other disciplines), but there are further improvements we continue to work towards.


For further news details:

Three engineering subjects rank in the world’s top 100 | Engineering | University of Waterloo

See the link below for the full story, but nice to see my department (Chemical Engineering) ranked in the top 100 worldwide.  The two others are Electrical Engineering (49th) and Civil Engineering (51 to 100 range).  Mechanical Engineering ranked in the top 150.

Waterloo Engineering notched three top-100 results in the Quacquarelli Symonds (QS) worldwide university subject rankings released today for 2019.

Source: Three engineering subjects rank in the world’s top 100 | Engineering | University of Waterloo

Cruise Ship Air Quality

An interesting news story about the measurement of air quality on cruise ships appeared recently.  Specifically, it dealt with the concentration of ultrafine particulate (UFP) matter in the air on four cruise ships, measured by a researcher from Johns Hopkins University.  UFP is invisible matter with diameters of around 100 nanometres (nm), which is about  1,000 times smaller than a human hair, and it is implicated in airway inflammation and effects on other organs in the human body.  Being interested in air quality, I looked up the actual study report which you can also read here.  Here is my take on the work and meaning… Continue reading

Ontario’s Refundable Fee Plan

The Ontario government recently announced a 10% tuition discount, as I mentioned earlier.  Along with that, they also announced that many fees will have to be made refundable for any student that doesn’t want to pay them.  The theory is that it will give “students more choice over the fees they pay” and save students money on top of their 10% discount.  It’s quite unusual for governments to start micro-managing university fees, many of which were set up to address local conditions and concerns with student support via a referendum.  There is an exception in the announcement however, and fees that “fund major, campus-wide services and facilities or fees which contribute to the health and safety of students are deemed mandatory”.  These mandatory fees include walksafe programs, health and counselling, athletics and recreation and academic support.  So, I was interested in how this affects engineering students at Waterloo, and compiled a list of fees (to the best of my ability).  It’s complicated but here they are with some comments and observations. Continue reading

Cannabis Air Emissions

With recent moves to permit sales of cannabis in Canada and some U.S. states, commercial operations are popping up in various locations.  Whenever new industries emerge, there are often new environmental impacts to consider and air pollution seems to be an increasingly common problem with cannabis too.  Not from smoking, but rather from the greenhouse operations where it is grown under lights in high-density conditions to save space.  It turns out that these intensive grow operations can have vented air emissions that are rather smelly, as this one news item describes.

Like all plants, cannabis emits volatile chemical compounds at various stages in its growth.  Some work has been reported in research literature, identifying over 200 chemicals in the air, although I suspect that paper missed a lot of odorous sulfur compounds that are often associated with “skunky” smells.  A lot of the odor compounds are terpenes or their relatives (e.g. limonene, pinene, linalool), and the paper mentions cymene, benzaldehyde, nonanal, and decanol as key odor chemicals.  None of these compounds are particularly hazardous (at least at the normally low concentrations found around plants).  None of them are specific to cannabis either.  Lots of them are produced by various plants, in varying amounts and combinations.  A lot of plant-based essential oils that you can buy contain similar chemicals.

The environmental issue arises if the odor interferes with the neighbouring property and their ability to use and enjoy their property.  The Ontario government website has some information about odors and property-owner rights .  Under Ontario’s Environmental Protection Act (Section 14) odor-emitting industries can get into legal trouble because they are emitting a “contaminant” that causes an “adverse effect”.

From an engineering point of view, the control of odorous emissions like this is not unlike many other industries with odour concerns, like sewage treatment plants, rendering plants, some food manufacturers, and some chemical manufacturers.  The first step is containment, so that odor emissions are not just leaking out of the buildings from a multitude of locations.  If everything can be efficiently captured in one or two well-controlled ventilation systems, then emissions controls can be applied to those vent streams before they discharge into the environment.

It’s not clear at this point what type of emission controls are best for both efficiency and cost points of view.  Usually there are several possible solutions, so engineers have to figure out which one is the most cost-effective.  Standard approaches to odor control run a range of technologies from wet scrubbing to activated carbon capture, to biofiltration and possibly photochemical oxidation.  High temperature thermal oxidation is another option, but probably overkill and too expensive for this application.  One solution may not fit all commercial operations either.  Each location would need a thorough engineering analysis and assessment for a good recommendation, which is something done by chemical and environmental engineers (and some mechanical engineers too).  Companies that rushed into production without doing these assessments may get stuck with expensive retro-fits once the Ministry of Environment comes knocking.

So, with every new “industry” there are issues that come up that may or may not have been anticipated by the business people.  Those issues will keep regulators and engineering consultants busy for a while.

Ontario’s New Climate Change Plan

The new Ontario government recently released their plan to tackle carbon emissions and climate change.  This comes after scrapping the previous government’s relatively new cap-and-trade scheme that was set up in collaboration with Quebec and California.  Below I’ll give a detailed analysis of various parts of the plan, but here is my high level overview.  There are some promising bits and pieces (without knowing a lot of details yet), but it is relatively unambitious and somewhat odd in its approach.  This new government has generally focused on reducing regulation and taxpayer-funded spending, but this plan implements additional regulations and uses tax money to subsidize industry.  This seems inconsistent.  If you want to see the plan and comment, here is the link.  Now for my detailed analysis… Continue reading