Autism and Air Quality

Autism, or more accurately Autism Spectrum Disorder (ASD), is in the news and public view a lot in recent years.  According to some recent reports, it is now diagnosed in 1 out of 68 children (1.47%) in the U.S.  Reasons for the apparent increase in diagnoses over recent decades are complex, but they lead us to wonder what is happening and what are the causes?

Recent scientific literature suggests that the specific causes are largely unknown, but there is a very strong genetic component (heritability of 80%).  Unfortunately, even the genetic aspects are very uncertain and probably highly complex, not just a simple set of genes like the ones that determine your eye colour.  Although genetics may play a large role, there are also indications that environmental factors are involved, perhaps in some sort of interaction with the genetic factors.

The popular and social media keep going in circles about vaccines, a factor for which there is no reliable scientific evidence at all.  At the same time, there seems to be complete ignorance of a growing body of scientific literature linking ASD with air quality.  A quick search through peer-reviewed scientific literature using the Scopus database shows at least 160 papers that mention “autism and ‘air pollution'” somewhere in the publication over the past 20 years.

I don’t know a lot about ASD, but I can comment on air pollution and so here I’ll discuss what I see from some of this literature.  Much of the research literature is only fully available if you have access to a university library (like me), but I’ll try to provide some links to at least the summary or abstract of the studies.  Much of this literature is highly technical however, so don’t worry if it’s not so easy to digest.

Continue reading

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

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.

New powder could reduce greenhouse gas emissions | Engineering | University of Waterloo

Some interesting results from my colleague’s research group.  I add some further context below the link…

Researchers at Waterloo Engineering have created a powder that could be used to reduce greenhouse gases at factories and power plants that burn fossil fuels. The advanced carbon powder, developed using a novel process in the lab of chemical engineering professor Zhongwei Chen, could filter and remove carbon dioxide (CO2) from emissions with almost twice the efficiency of conventional materials.

Source: New powder could reduce greenhouse gas emissions | Engineering | University of Waterloo

My Context/Analysis:   Some interesting work in materials science and chemistry.  From the published paper (sorry it’s behind a paywall, but I can read it through the university’s subscription), I can see that the amount of CO2 captured is about 1.6 mmole of CO2 per gram of powder, or about 70 mg/g, at flue gas conditions.  As the paper points out, this is pretty good for CO2 adsorption, but it is not a miracle cure for all of our problems.  To put it in context, in 2016 the U.S. electricity sector emitted something like 1,800,000,000,000 kg of CO2 (from the EPA website).  So, if the powder can capture 70 mg per g it would take about 26,000,000,000,000 kg of powder for one year of capture.  That’s a lot of powder!!  And that’s only for one sector in the U.S. alone (representing about 28% of U.S. CO2 emissions).  So, it’s important to continue doing research, find new things and look at potential applications in a wide range of fields.  But carbon emissions and climate change is a huge problem and there aren’t any easy answers.  Reducing CO2 emissions will generally be better than trying to capture them afterwards, like the three R’s hierarchy (reduce, reuse, recycle).

New X-ray technology in testing with cancer patients 

Interesting research project in our Electrical and Computer Engineering department.  Reduces the need for CT scans and their high radiation doses.

A digital X-ray imager developed by a Waterloo Engineering startup is being tested on cancer patients with lung nodules in a pilot study at Grand River Hospital in Kitchener.

Source: New X-ray technology in testing with cancer patients | Engineering | University of Waterloo

AIChE Fellow Frances Arnold Is One of Three Winners of 2018 Nobel Prize in Chemistry | AIChE

Nice to see a Chemical Engineer receive a Nobel prize, for work on random mutagenesis for industrial enzyme selection and improvements.  My PhD work was in enzyme applications, though not this particular area.

Dr. Arnold’s research has produced methods now routinely used to create new catalysts. Her work has led to new enzymes for pharmaceuticals, sustainable biofuels, and other environmentally friendly products.

Source: AIChE Fellow Frances Arnold Is One of Three Winners of 2018 Nobel Prize in Chemistry | AIChE