Aerosol sensor expert Winnie Chu is passionate about workplace air quality

During Winnie Chu’s doctoral program in materials chemistry at Simon Fraser University, she had created a new solid-state material for detecting nitrogen oxide (NOx) air pollutants and established a theory of how the material worked. That was enough for the thesis, but not enough for Chu. She wanted to build a device to prove the material worked, so she persuaded her adviser to introduce her to some electrical engineers, from whom she learned enough to work in clean rooms and build the sensor.

Chu’s drive to put theory into practice later propelled her to jump from academia to industry. In 2007, she founded Nanozen as a consulting company. In 2015, she transformed it into a spin-off from the University of British Columbia. Nanozen now has 20 employees and makes a wearable, real-time aerosol exposure monitor for hazardous aerosols in the workplace such as silica, wildfire smoke, airborne active pharmaceuticals, and the mining particulates coal, iron, copper, diamond, and lead.

Louisa Dalton talked with Chu, now Nanozen’s chief technology officer, about her efforts to invent new methods for aerosol detection and to push industry to require real-time aerosol monitoring for workers. This interview was edited for length and clarity.

Tell me how a master’s in quantum mechanics, a PhD in materials chemistry, a postdoc in electrical engineering, and a career in aerosol exposure come together.

I’m just very curious. I’m interested in everything. To my surprise, it actually all has come together. In undergrad and graduate work, I focused on going deep into chemistry. But because I also know electrical engineering to a certain extent, I now have the experience and background to know what’s possible and what’s not. I am able to communicate in two fields and create something that combines both chemistry and electrical engineering.

How did you get interested in aerosols in the workplace?

During my studies, I was detecting hazardous gases in the air. Then I discovered aerosols. And I realized, aerosols are so important, but there’s very little research on aerosol workplace exposure out there. Industries create the highest concentrations of aerosols. That’s why I started to focus more on workplace aerosols: physical, chemical, and biological aerosols.

Can you give some examples of hazardous aerosols in the workplace?

In mining and construction, silica is especially harmful. People call it the second asbestos because once silica gets into your lungs, your lungs have a hard time clearing it. Scar tissue starts to form bumps just trying to clear it, and that eventually causes cancer and COPD [chronic obstructive pulmonary disease].

Other harmful aerosols that haven’t been broadcast as much are in the pharmaceutical industry. All drugs have side effects, and most are toxic at exposure levels higher than their prescribed doses. If there’s any leak at all when manufacturing a drug, and operators don’t have proper protective gear, they will inhale the aerosolized chemical. Some of these are million- or billion-dollar drugs, but they require containment systems just to make sure they don’t get into the workplace or the environment.

What was your goal when you started Nanozen?

Unfortunately, even in mining silica, the current regulatory approved method for testing worker air quality is to pump aerosols onto a filter and then send the filter away to an accredited lab and wait for the result. Imagine that you have to tell your workers, “Oh, by the way, a month ago, the air was not acceptable.”

Imagine instead the power of a real-​time monitor—one that can actually tell you that it’s dangerous now, to get out. Or even one that can identify where the leaks are. This is my passion.

I want to change the status quo from pump, filter, and analyze to real-time monitoring to effectively protect workers in the industry.

Talk about Nanozen’s DustCount monitor.

A lot of safety and occupational health officers at companies realize they need real-time monitoring. But the accuracy and precision of available monitors haven’t been acceptable to them. We created Nanozen’s wearable DustCount monitor so it would be real time but still maintain accuracy and precision. It uses optical detection with time-of-flight features to determine the size and concentration of aerosol particles.

Our monitor is different from others because we designed every single optical and mechanical component ourselves. A lot of people are using optical detectors and optical particle counters, but they usually use off-the-shelf components and then put things together. Using those, you’re not going to get the accuracy and precision you need.

Are you involved in helping set exposure standards in the US or elsewhere?

Not directly. In the US, the agency that enforces occupational health guidelines is OSHA, the Occupational Safety and Health Administration. The research arm is NIOSH, the National Institute for Occupational Safety and Health. NIOSH has a lot of our monitors. We work closely with NIOSH to feed a lot of data to OSHA—eventually for the agency to make a decision on regulatory change. In Canada, Australia, and South Africa, we are involved in a similar manner. We all hope that the regulatory agencies change to adopt real-time monitoring. Unfortunately, in occupational health, innovation drives regulation rather than the other way around.

One trend driving real-time monitoring is for big companies to use ESG [environmental, safety, and governance] ratings—a rating calculated by third parties to measure how well a company treats its employees and the environment—to guide their environmental and health and safety impact. For mining and pharmaceutical companies, these are very important. Our real-time monitor directly linked with data in real time really helps companies improve their ESG rating. It’s good for a company at the site level—taking care of workers’ health and safety—and at the executive level, for the people who pay attention to the ESG.

What are you working on now?

I’m focusing on helping the pharmaceutical industry, to build our models to be exactly what the pharma industry needs.

Our next-generation DustCount monitor can indicate which chemicals it detects, not just particle size. We call it the aerosol spectral analyzer. It measures how particles scatter light from multiple lasers to tease out the fingerprints of different chemicals. We have a prototype on trial with major pharmaceutical companies, and it should be out by the end of the year.

Also, the pharmaceutical industry is changing from working with small molecules to biopharma—peptides and proteins. Detecting those aerosols in the air is even more challenging because peptide protein aerosols are not usually uniform. That’s the research-stage next generation we are working on.

Louisa Dalton is a freelance writer based in Virginia who covers chemistry. A version of this story first appeared in ACS Chemical Health & Safety: cenm.ag/winniechu.