Your favorite professional football or soccer team may be suffering from butterfingers -- or in this case, butterfeet -- but this may not be the only thing keeping them down.
In the past, teams have attempted to explain the dilemma by saying the ball is too bouncy or the pitch is too small, and even going as far as saying they are forced to play in the wrong colors kit.
Now, a group of German health economists has found another factor that may be affecting the performance of football players. The culprit? Air pollution.
Scientists at the IZA economic institute will present their findings [PDF] at this year's annual Royal Economic Society meeting in Brighton. Their study is based on analysis of the form of players in Germany's Bundesliga from 1999 to 2011.
The research team, which is comprised of Andreas Lichter, Eric Sommer, and Nico Pestel, measured the total number of passes each player made in their official matches.
The number of passes is not used as a measure of physical performance, the team said. Instead, it serves as the productivity indicator because it is related to the speed of the game.
More importantly, the team said the quantity of passes is vital to a team's success by retaining possession of the ball and creating opportunities for scoring. It also provides a reliable indicator in which passing is the nature of the game, limiting the roles of chance.
After calculating the number of passes, it was then compared against hourly air pollution data which was gathered by the German Federal Environment Agency outside each stadium.
The health economists discovered that at kick-off on any given match, the concentration of pollution or particulate matter was 23.8 micrograms per cubic meter. In nearly half of the games, the level of pollution ranged between 20 to 50 micrograms per cubic meter.
The European Union's threshold for particulate pollution regulation is at 50 micrograms per cubic meter. This limit was exceeded in 7 percent of the games.
With that, researchers found that the performance of players was hindered by pollution even at low levels. High levels above the EU threshold revealed a significant decline in performance by as much as 16 percent.
Players who were aged above 30 years old as well as players who exert large numbers of passes were most affected. The productivity of midfielders and defenders were also affected.
"Our analysis highlights that economic consequences of environmental pollution are not limited to adverse impacts on population health," the team wrote.
Additionally, the research team found that the shorter the gap was between matches, the more pronounced were the air pollution effects.
Meanwhile, there is some evidence that players may be adapted to the higher levels of air pollution and that they may tend to adjust their style of play.
The findings are most likely to be examined further than the world of professional football. Scientists also want more work to be done to evaluate the effects of air pollution on other professions and broaden the positive effects of environment regulation.
Photo: Piotr Drabik | Flickr