Posts Tagged: air quality

The UrbanScanner Project: Mobile monitoring of air pollution in cities

Prof. Marianne Hatzopoulou (left) and her research team, comprised of MASc candidate Keni Mallinen (centre) and Arman Ganji , PhD (right), with the UrbanScanner on the Uof T campus. UrbanScanner is  a rolling laboratory capable of monitoring air quality, traffic, trees and built environment in urban settings. (Photo by Phill Snel)


What rolls around the city getting a lot of admiring looks for its flashy chromed finishes and high tech roof protrusions? It’s not the latest tech from a popular web search engine company; it’s something entirely different. Meet UrbanScanner, a mobile testing laboratory on wheels, in the form of an automobile, researchers are driving around Toronto to monitor air pollution.

The Transportation and Air Quality (TRAQ) research group within the Department of Civil & Mineral Engineering at U of T, led by Prof. Marianne Hatzopoulou, has partnered with Scentroid, a Toronto-based company developing sensor-based systems for urban air pollution monitoring. The result is the development of UrbanScanner.

Hatzopoulou’s team, comprised of research associate Arman Ganji, PhD and Keni Mallinen, an MASc candidate, has been getting a lot of looks while gathering their data, but little is known about this mysteriously well-equipped rolling lab.

Watch an introductory video:

With a 360-degree camera, LIDAR (Light Detection and Ranging), GPS, an ultrasonic anemometer, temperature and relative humidity sensors, as well as particulate matter and gas sensors, UrbanScanner can monitor air pollution in a variety of methods. A platform on the roof of the vehicle streams data to a cloud server, with air pollution measured every second and paired with the camera and LIDAR images.

An example of UrbanScanner data points collected for pollution concentration overlapped with a City of Toronto street map.

Besides air quality, the traffic, trees and built environment are constantly measured. All of the data is overlaid over city maps with the aid of GPS, allowing for real-time measurements of traffic flow, number and height of trees, as well as building forms. With the ability to measure air flow and pollution near built-up urban areas, the maps can reveal elevated pollution levels, especially at rush hour and depending upon the season.

All of the data collected thus far takes time and effort to process, but Hatzopoulou has plans going forward. “Since September 2020, UrbanScanner has been collecting air quality data across Toronto, both along major roads and within Toronto neighbourhoods,” she says. “These data were paired with images of the urban environment from the UrbanScanner camera and these images will be analyzed to extract important features that affect air quality. This massive database will continue to grow as UrbanScanner collects data across seasons and will help us predict air quality in space and time, providing crucial information about population exposures in the City.”

A graphical abstract for the UrbanScanner project shows urban routes, samples taken and mapping.

Hatzopoulou adds, “Our team is also working on a smaller, more compact version of UrbanScanner with multiple units that will be installed on commercial/delivery vehicles. Imagine a dozen UrbanScanners collecting data simultaneously every day in Toronto!”

The research team is also developing a website to share data from the UrbanScanner project with the public and working on ways to enhance public engagement around urban air quality.

So, now if you see UrbanScanner in your neighbourhood you’ll know exactly what the team is up to. Please feel free to take a snap and tag #UrbanScanner and @CivMin.

By Phill Snel


By the numbers:

~250,000 • Number of data points collected in a month.

2,280 • Kilometres driven in a month of study.

101  • Hours of collection data.

60 • Kilometres driven each day of monitoring.

14 • Sensors on UrbanScanner.

4 • Wheels.

3 • Researchers.

2 • Seats in UrbanScanner.

1 • Mobile laboratory platform.

~ CivMin ~





Modelling the health benefits of electric cars

Professor Marianne Hatzopoulou (CivMin) and her team have modelled the potential human health impacts of a large-scale shift to electric vehicles across the GTHA. (Photo: Roberta Baker)

Electric vehicles are often touted as a means of mitigating climate change, but a new modelling study suggests that their public health benefits may be just as significant.

“Local air pollution within urban environments is highly detrimental to human health,” says Professor Marianne Hatzopoulou (CivMin), who led the research. “When you have an electric vehicle with no tailpipe emissions, you’re removing a wide range of contaminants — from nitrogen oxides to fine particulate matter— from the near-road environment and shifting them to power plants. The net effect remains a large improvement in air quality.”

Health Canada estimates that 14,600 premature deaths per year can be attributed to air pollution, with more than 3,000 of these in the Greater Toronto Hamilton Area (GTHA). Hatzopoulou and her team set out to model how that might change under a significant shift from internal combustion vehicles to electric ones.

The researchers created computer simulations for a number of different scenarios, such as replacing 20%, 50% or 100% of all cars and SUVs in the GTHA to electric ones. They also modelled the effect of switching transit buses over to electric buses, and of replacing all transport trucks with newer, less emitting models.

The simulations accounted for the fact that even though electric vehicles don’t produce any emissions themselves, they increase demand on electricity plants. If those plants burn fossil fuels, they might show increased local emissions, which the team included in their model.

“We can simulate the air quality down to areas as small as one square kilometre, so even if the overall effect is positive, we can see if there are local winners and losers,” says Hatzopoulou. “We also accounted for air pollution drifting over from upstate New York and the American Midwest, which we often can detect here in Toronto.”

For each scenario, the team calculated the predicted reduction in emissions for various air pollutants. Using epidemiological data on pollutant exposures, they then estimated the reduction in premature deaths that would be observed in that scenario.

Finally, using an economic measure known as the Value of Statistical Life (VSL), they converted the reductionin deaths into a dollar figure, as a way of quantifying the social benefits of the change.

Among the model’s predictions were:

  • Converting all cars and SUVs in the GTHA into electric vehicles would cause 313 fewer deaths per year, an estimated social benefit of $2.4 billion
  • Converting all transport trucks to more efficient models would cause 275 fewer deaths, an estimated social benefit of $2.1 billion
  • Converting  all transit systems to electric buses would cause 143 fewer deaths, an estimated social benefit of $1.1 billion

I was surprised just how strong the effect was,” says Hatzopoulou. “If you bring it down to an individual level, each electric vehicle replacing a gas-powered one brings nearly $10,000 in social benefits. Those benefits are shared by everyone, not just the people buying the cars.”

The study was published today in a report co-authored with Environmental Defence and the Ontario Public Health Association. The analysis relating to transport trucks, which included contributions from U of T Engineering professors Matthew Roorda and Daniel Posen (both CivMin) and their teams, was published last month in the journal Environmental Research.

NextHatzopoulou and her team plan to use their model to study the effects of other changes, such as reducing the overall number of cars on the road by encouraging public transit or active transportation.

“Electric vehicles are great, but with even millions of them on the road, we would still have issues such as traffic congestion,” she says. “If we want to address the climate crisis, we’re going to need behavioural modifications as well.”

“One of the things we’ve learned during this COVID-19 pandemic is that it might not be critical for everyone to commute to work every dayWe would liketo quantify the benefits — both for the environment and for our own health — of making those kinds of changes.”

By Tyler Iriving

This story originally published by Engineering News

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