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 years, researchers have been connecting the dots between air pollution and poor job performance: In 2011, for instance, a study found that outdoor agricultural workers' productivity declined as atmospheric ozone levels increased. A 2014 follow-up study found that blue-collar indoor workers were similarly affected by levels of outdoor air pollution.
But at that point, it still wasn't clear whether those findings held for office workers too. Desk work is both indoors and far less physically strenuous than packing fruits and vegetables in a warehouse, so one might reasonably conclude that white-collar workers are less vulnerable to the effects of air pollution simply because they're not breathing in as much air.
But that's not the case, as the latest study concludes. For the paper, Steffen Meyer and Michaela Pagel took data on stock trades made by more than 100,000 private investors in Germany from 2003 to 2015 and paired the information with data on air quality, weather and traffic from the closest of more than 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 explained. The stock data is particularly useful because it enabled 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 whether these fluctuations had any effect on individual investors' propensity to log in and make a trade.
To isolate the effect of air pollution, they'd first need to control for a 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 they are linked to asthma, general respiratory distress, heart attacks and even death.
The researchers found that a modest increase in outdoor PM10 — 12 micrograms of the pollutant per cubic meter — reduced investors' propensity to trade by nearly 10%. They characterized 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 pointing out 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 zero and 40 micrograms, and often more than that.
"To the best of our knowledge, this paper is the first to test whether air quality affects investor willingness to sit down and trade, controlling for investor-, environment- and market-specific factors in a commonly found low-pollution environment," the authors concluded. "The negative effects of pollution on white-collar work productivity are much more severe than previously thought."
The finding comes at a time when federal authorities in the United States are working to undo certain air quality regulations. In particular, a number of President Trump's appointees to the Environmental Protection Agency have raised eyebrows for rejecting the broad scientific consensus on the effects of air pollution.
UC Irvine's Robert Phalen, for instance, believes that "modern air is a little too clean for optimum health." Michael Honeycutt, the new chairman of the EPA's Science Advisory Board, has written that federal regulations on ozone are unnecessary because "most people spend more than 90% of their time indoors."