Recent research has uncovered a dual role for plants in air quality; while they are known for cleansing the air, they can also contribute to pollution by emitting isoprene, a chemical released as a defense mechanism against pests.

Isoprene production in plants triggers an increase in Jasmonic acid levels, which makes plant proteins more difficult for insects to digest, effectively serving as a defense strategy.

Insects that feed on isoprene-emitting plants experience stunted growth due to digestive issues linked to this chemical, although isoprene itself is not toxic.

Experiments conducted at Michigan State University demonstrated that bioengineered tobacco plants emitting isoprene were less affected by tobacco hornworms compared to their non-emitting counterparts, highlighting isoprene's effectiveness in deterring pests.

Plants primarily produce isoprene under extreme conditions, such as heat stress, utilizing up to 2% of their stored carbon for its synthesis, which underscores its importance in plant defense.

A recent study published in Science Advances has confirmed isoprene's role as a natural insecticide, a hypothesis that had remained unproven for decades.

This discovery presents researchers with a dilemma: whether to enhance isoprene production in crops for improved pest resistance or to reduce it to safeguard air quality, creating a complex challenge for future agricultural bioengineering.

However, isoprene is classified as a volatile organic compound (VOC) that, when released into the atmosphere, contributes to ground-level ozone formation, a harmful pollutant linked to respiratory problems.