During the 2010 Fédération Internationale de Football Association (FIFA) World Cup, it seemed to me that as much of the commentary was devoted to the vuvuzela as it was to football (known as soccer here in the US). Most fans seemed to either embrace or despise this ~60cm elongated plastic horn, which is popular in many African and Asian countries and can generate noise levels of up to 127 decibels—approximately equal to the pain threshold. I was first exposed to the vuvuzela while half-heartedly watching the 2010 FIFA World Cup as my British husband tried to explain the rules of the game. I don’t remember much about the game of football/soccer, but I do remember the loud, unrelenting and monotonous sound of those ubiquitous plastic horns. I couldn’t quite fathom the instrument’s popularity for several reasons: 1) The cacophony in the stadium drowned out any hope of hearing the commentators, 2) the instrument seemed to allow no variation in pitch or tone and 3) I felt sorry for the players and fans in the stadium who were being subjected to the ear-splitting noise, even though the fans seemed to be loving every minute of it. Perhaps I would have come down on the other side of the vuvuzela fence if I were more of a football/soccer fan and had been caught up in the fanfare associated with sport’s biggest contest, but I will admit that I was one of the vuvuzela haters.
I had to chuckle recently when I learned that I have yet another reason to dislike the vuvuzela: The instruments generate more than just noise; they also generate respiratory aerosols.
Respiratory aerosols are no laughing matter however. They are just one example of airborne particles that can assist transmission of diseases such as tuberculosis, measles, the common cold, influenza, rubella and severe acute respiratory syndrome (SARS). These aerosols are formed during coughing, sneezing, talking and other activities where air is expelled from the lungs. This is why your mother warned you to cover your mouth when you sneeze or cough. Recently, researchers have shown that blowing into a vuvuzela generates a lot more airborne particles than another popular way of showing support for your team: shouting (1).
As part of these experiments, Ka-Man Lai and her colleagues asked male and female volunteers to blow into a vuvuzela or shout into a paper cone that was the same length and had the same exit diameter as a vuvuzela. A laser particle counter was used to measure the number of airborne particles leaving the opening of the vuvuzela or cone, and a hot-wire anemometer was used to measure air velocity. The researchers determined that the vuvuzela generated an average of 658 × 103 particles per liter of air, whereas shouting generated only 3.7 × 103 particles per liter. Taking into account the average volume of air expelled by both groups (6.1 L/s for vuvuzela blowers and 1.8L/s for shouters), they calculated each vuvuzela generated as many as 4 million particles per second, while shouting generated only 7,000 particles per second. Consider that the average duration was 2.1 seconds for vuvuzela blowing and 2.2 seconds for shouting, and that equates to 8.4 million particles for the vuvuzela and 15,400 particles for shouting. What a difference the vuvuzela makes!
Not all particles are created equally. Medical experts have determined that aerosol droplets larger than 100µm in diameter do not usually remain airborne long enough to pose much of a danger. However, much smaller droplets can remain aloft for hours or even days and can be breathed in by other people. Droplets greater than 5µm are likely to remain in the upper airway, but droplets smaller than 5µm are more likely to reach the alveoli in the lower lung. For this reason, the researchers determined particle size for both methods of cheering on your football/soccer team and found that the majority of particles (97%) were in the range of 0.5–5.0µm. So, not only could the vuvuzela ruin your hearing, it could also increase the risk of disease transmission.
I’m not a football/soccer fan (although American football is an entirely different story. Go Packers!). I probably won’t actively watch the 2014 World Cup games, although I will be exposed to second-hand football/soccer while my husband watches the games. I really hope that the vuvuzela doesn’t make another appearance at the 2014 World Cup in Brazil. Unfortunately, Wikipedia’s entry about vuvuzelas informs me that similar horns have been used in Brazil since the 1960s, so my hope might be for naught. Well, at least football/soccer fans who plan to attend the games have some time to buy a good set of earplugs and a mask to cover their noses and mouths.
Reference
- Lai, K.M., Bottomley, C. and McNerney, R. (2011). Propagation of respiratory aerosols by the vuvuzela. PloS one 6, e20086
Terri Sundquist
