A new study from a German economic institute has found that when you are having a bad game, it may not be all in your head. After reviewing nearly 3,000 soccer matches in the country between 1999 and 2011, the researchers found that air pollution significantly affects the performance of professional soccer players.
Or, as they put it, the "results confirm and extend recent evidence on the negative effects of ambient air pollution on short-run productivity."
While soccer may not seem like a short-run activity, what the authors mean by this is that soccer games present a great atmosphere in which to measure and compare the impact of air pollution levels on the intense exertions of individuals in a way that is otherwise not readily available through consistent, reliable data.
In reaching their conclusions, the three economists conducting the study measured the total number of passes that each player made. They determined that when ambient air pollution exceeded the European Union regulation threshold for particulate pollution of 50 micrograms per cubic meter—which happened in 7% of the matches—player performance declined by as much as 16%. Furthermore, they found that player performance suffered from pollution even when it was well below the health limitations.
In the United States, the Environmental Protection Agency has set particulate matter standards at 150 micrograms per cubic meter, 3 times higher than the EU standard, under the Clean Air Act—this is for PM10, which includes all particulate matter smaller than ten micrometers, the baseline used in the study. There are much tighter regulations for PM2.5, or particulate matter that's smaller than 2.5 micrometers.
In around 44% of the matches covered in the German study PM10 levels ranged between 20 and 50 micrograms per cubic meter, with the overall mean being 23.8 micrograms per cubic meter.
The researchers at the IZA economic institute in Bonn, Germany, which focuses specifically on labor issues, explained to the Guardian how they settled upon using number of passes as an indicator of performance.
“While the number of passes is not a measure of physical performance per se, it serves as our preferred productivity indicator since it is related to the speed of the game and, importantly, is highly relevant for a team’s success by retaining ball possession and creating scoring opportunities,” they said. “Moreover, passes provide a reliable measure, as passing is the essential nature of the game, which limits the role of chance.”
The researchers found that another undesirable quality, increased age, exacerbates the troubles posed by air pollution, writing that players over 30 exhibited larger negative effects. The same amplified negative impact was observed when players had fewer rest days between matches.
Player position also played a role.
"Moreover, midfielders’ and defenders’ productivity is particularly affected by pollution, players who are more attached to the game and exert a larger number of passes," they wrote.
When it comes to adapting to the conditions, as soccer players are forced to do for matches taking place in the cold, rain, snow, or otherwise undesirable weather, they found that players tend to "marginally adjust" by making slightly more long passes rather than short passes.
In the end, the researchers—they are economists after all—link the study's findings back to economic impacts:
Overall, our analysis highlights that economic consequences of environmental pollution are not limited to a worsening of population health. High concentrations of particulate matter negatively affects the short-run productivity of professional soccer players to a considerable extent, confirming and extending empirical evidence on negative productivity effects of air pollution for low-skilled workers.
While sports require a lot of short-run exertion, so do many low-skilled jobs in fields like construction, agriculture, and social services. When workers are forced to undertake these jobs in polluted environments, their performance likely suffers, which causes ripple effects throughout the economy. And that's not a goal for anybody.
Furthermore, according to the EPA, "each day, air pollution causes thousands of illnesses leading to lost days at work and school. Air pollution also reduces agricultural crop and commercial forest yields by billions of dollars each year."