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The Journal Gazette

Sunday, December 03, 2017 1:00 am

Study: Indoor workers affected by air quality

Christopher Ingraham | Washington Post

Poor outdoor air quality is likely to have a negative impact on your job performance, even if you work indoors at a desk, according to a new working paper from researchers at Germany's Leibniz University and the Columbia Business School.

For the paper, Steffen Meyer and Michaela Pagel took data on stock trades made by over 100,000 private investors in Germany from 2003 to 2015, and paired it with data on air quality, weather and traffic from the closest of over 1,600 monitoring stations.

Why stock trades? “We interpret individual investor trading, an indoor activity that requires some skill and cognitive but no physical exertion, as a proxy for willingness and ability to engage in office work and thereby white-collar productivity,” Meyer and Pagel explain. The stock data is particularly useful because it allowed the researchers to measure human behavior at the individual level.

Outdoor air quality can fluctuate significantly from day-to-day. Meyer and Pagel wanted to know if these fluctuations had any effect on individual investors' propensity to log in and make a trade on a given day.

To isolate the effect of air pollution, they'd first need to control for a whole host of other factors known to affect trading behavior: day of the week (markets aren't open every day), day of the year (markets are busier at certain times of year), preceding market returns, changes to daylight saving time, weather and traffic.

With those other factors accounted for, Meyer and Pagel focused on the effect of particulate matter in the air, a measure known as PM10 – particles about 1/7th the thickness of a human hair, small enough to be inhaled deep into the lungs. These particles come from vehicle exhaust, construction dust, industrial sources, wood burning and other sources, and are linked to things from asthma to general respiratory distress to heart attacks and even death.

They found that a modest increase in outdoor PM10 – 12 micrograms of the pollutant per cubic meter – reduced investors' propensity to trade by nearly 10 percent. They characterize that effect as “large and significant,” akin to the decrease in trading observed on a nice sunny day versus a cloudy one.

It's worth noting that a 12 microgram increase in PM10 is not a whole lot – on any given day in Germany, levels of the pollutant usually fluctuate between 0 and 40 micrograms.

The finding comes at a time when federal authorities in the United States are working to undo certain air quality regulations.