The house lights go down, a hush falls over the audience, and a single beam of light traces a path through the theatre. If you’ve ever been to a show, a concert or play, local to Broadway, you‘ve probably seen the laser beam of lights adding to the drama.

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A good light show can make or break a production and stage fog is a critical tool in the light crew’s kit. But since we’re talking air pollution, you’re probably thinking Wait a minute, that mist can’t be great for the air quality in those old theatres…

We caught up with Broadway musician, fiddler extraordinaire, and air quality expert Caitlin Warbelow to find out what concerns she has about her regular and extended exposure to theatre fog.

Caitlin Warbelow has been ‘draggin the bow’ professionally from kitchen parties to Broadway and she’s no stranger to a dramatic stage show. After several of her fellow performers were taken ill with respiratory issues, she started to suspect a link between these illnesses and the effects of chronic exposure to stage fog.

Here’s her story in her words.

As part of my masters thesis in Urban Planning and Geographic Information Systems at Columbia University, I conducted outdoor air quality research transects in Harlem using mobile air quality sensors attached to the back of a bike. Though my professional path in the last ten years has lead me to music, I remain a scientist and data analyst at heart! As soon as I realized that myself and others at my theatre were experiencing respiratory issues, the next obvious step for me was to draw upon my background in air particulate research.

I suspected that the stage haze that is used to create lighting effects was contributing to negative health outcomes, and I wanted to collected data and analysis to support that hypothesis.  Back when I did my research at Columbia, the available monitoring technology was physically very large, so I was extremely excited to find a device as small and quiet as Flow, which allowed me to take measurements without disruption to the show. I’ve been able to test the air quality onstage as well as in my dressing room, which gives us a sense of what the actors, musicians, crew, and audience are being exposed to on a daily basis.

You can see very clearly when the shows are happening – there are massive spikes in PM2.5 and PM 10. We now have at least six people at our show who are suffering from major respiratory issues, some of which have required surgery.

Digging into the data

According to the World Health Organization “There is good evidence of the effects of short-term exposure to PM10 on respiratory health, but for mortality, and especially as a consequence of long-term exposure, PM2.5 is a stronger risk factor than the coarse part of PM10 (particles in the 2.5–10 µm range).”

To help put Caitlin’s Flow data into perspective we use the Plume Air Quality Index (AQI) to categorize the different pollution levels into WHO exposure thresholds. Each of the Plume AQI categories indicates something specific about the length of time that you can be exposed to such pollutant rates without an adverse impact on your health.

“The spikes of particulate matter Caitlin has documented are very high—easily breaching the WHO hourly exposure threshold (equal to 100 in Plume AQI).” says dr. Boris Quennehen, lead atmospheric scientist at Plume Labs. “This is a good indication that Caitlin and her colleagues are being exposed to air pollution levels which may affect their health.”

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Now that she has confirmed her suspicions regarding high levels of PM in her workplace, Caitlin is continuing her research in an effort to find a way to make her theatre a healthier place for all who work there, as well as the thousands of people who see her show each week. .

Together, with researchers from Columbia University, and the Plume Labs team of atmospheric and data scientists, Caitlin will continue to collect data during shows with a variety of sensors to help tell her story and continue her fight for clean air.

To hear Caitlin’s music, check her out on Youtube, Bandcamp, or at her website. Stay tuned as the tale unfolds…

Do you have a story to tell about air pollution in your life? We’d love to hear it!

*1 NOTE Flow was left in dressing room during performance