Daniel Tkacik
Ph.D. Candidate in Civil and Environmental Engineering
Carnegie Mellon University


Floating right in front of you, there are hundreds of thousands of tiny particles— roughly 20 times smaller than the width of a human hair. Virtually invisible to us, scientists estimate that these particles may be responsible for tens of thousands of premature deaths by way of increased risk of cardiopulmonary disease every single year. But where do these particles (commonly known as “particulate matter”) come from? This is the mystery I am trying to solve.

We understand some sources, such as the exhaust coming out of a car’s tailpipe, or the emissions from a smokestack at a coal power plant, but particulate matter also forms in more covert ways. For example, the vapors in exhaust can undergo complex chemical reactions and transform into particulate matter. How those chemical reactions take place, and which chemicals are reacting are the questions I am trying to understand through my PhD dissertation research at Carnegie Mellon University.

In my experiments, I mimic the atmosphere’s actions on pollutants like vehicle exhaust and smoke from wood burning. I do this by placing the exhaust or smoke into a chamber covered in UV lights that simulate sunlight and then adding a mix of chemicals normally found in the atmosphere—these are the things we believe cause particulate matter to form. Then, I observe over time how the mix of chemicals changes. Using sensitive instruments I can observe the formation of particulate matter in the chamber

Before moving to Pittsburgh, I studied meteorology at Georgia Tech in Atlanta, Georgia. I’ve always been captivated by the science of the atmosphere, so studying the science of atmospheric particles has been a fun and fascinating experience.

When I’m not in the lab, I spend some time co-producing a science radio program and podcast called I Wonder… where my co-host and I try to answer fun, curious questions such as: “What makes a sad song sad?” or “When do we get our first memories?”

You can also find me outside on my bike enjoying Pittsburgh’s beautiful scenery or climbing its unforgiving hills.