Is the air inside a bell pepper the same as the air outside? This question is a perennial favourite, and a number of experiments have been conducted to get at the truth. The smooth, apparently poreless outer skin of a bell pepper, Capsicum annuum, leads to the supposition that the pepper cannot “breathe” and, therefore, that the air inside must have its own atmosphere.
Despite the shiny exterior, there is probably some limited diffusion between the inside and outside of the pepper – or the interior atmosphere would have an even higher level of carbon dioxide. One experiment into seed development in peppers artificially reduced the amount of oxygen inside the fruit – and this was found to affect the seeds adversely.
The conclusion was that the peppers have enough control over their inner microclimate to allow successful seed development.
As ever, answering one question raises others: does the air in peppers vary at day and night times? Does the air change as a pepper grows? And so on. Useful or not, internet speculation can continue for a while yet. Tests conclude that the air outside and the pepper’s internal air are different. Regular air contains roughly 78 per cent nitrogen and 21 per cent oxygen; “pepper” air has up to three per cent less oxygen and up to three per cent more carbon dioxide.