Climate & Environment
Tropospheric Ozone (O3)
Definition
Tropospheric ozone is ozone in the lower atmosphere, formed not by direct emission but photochemically, when sunlight drives reactions between nitrogen oxides and volatile organic compounds (including methane). It is the main component of photochemical smog, damaging respiratory health, reducing crop yields significantly, and acting as the third most important greenhouse gas after CO₂ and methane. It is classified as a short-lived climate pollutant, and its formation links air quality policy to climate policy through methane and NOx control.
References
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This reference provides supporting context for how “Tropospheric Ozone (O3)” is defined and used.
Overview
How it is used
The pollutant structures air quality standards and episodes management, methane mitigation co-benefit analysis, and agricultural damage assessment.
Why it matters
Tropospheric ozone is where the smog over cities quietly reaches into lungs, harvests and the climate system at once.