Atmospheric pressures

‘Poor indoor air quality hampers cognitive performance significantly’, concluded a recent study in the IZA (Institute of Labour Economics). Of course, ‘fresh air is good for you’ fits squarely in the category of things you knew already, but the research was specifically about chess: ‘An increase in the indoor concentration of fine particulate matter (PM2.5) by 10 µg/m3 increases a player’s probability of making an erroneous move by 26.3 per cent.’ Intriguingly, the effect seems most pronounced when players are in time pressure.
 
By my reckoning, that makes it pretty easy to induce mild stultification: burning a few incense sticks ought to do it. It’s scarcely credible now, but smoking at the board was once commonplace. The Soviet World Champion Mikhail Botvinnik is supposed to have enlisted his training partners to blow smoke in his face.
 
The celebrated 1972 Fischer-Spassky match was played in Reykjavik. The air is excellent there, and chess captured the public imagination like never before, though perhaps the political backdrop of the Cold War had more to do with it.