Envision science animation: The impact of chlorine on climate change and air pollution

This animated video takes a familiar element, chlorine, and reveals its unexpected significance in the lower atmosphere. Most people associate chlorine with swimming pools or cleaning products, or perhaps with CFCs and the ozone hole. But its role in the troposphere, the layer of atmosphere closest to Earth's surface, is far less understood and increasingly important to climate science.

Commissioned by PhD researcher Kathryn Vest as part of the Envision science communication competition, the animation introduces audiences to her atmospheric chemistry research and explains how rising levels of chlorine compounds in the troposphere could be influencing greenhouse gases, air pollutants, and our ability to predict future climate conditions.

animation Type

Research and Science Communication

Clients

The University of Nottingham Envision

Credits & Associates

Script written by Kathryn Vest and Mair Perkins
Direction by Kathryn Vest
Illustration by Mair Perkins
Animation by Mair Perkins

Research Insights

While stratospheric chlorine — the kind released by CFCs — has long been associated with ozone depletion, the behaviour of chlorine in the troposphere tells a different and less familiar story. A group of short-lived chlorine compounds known as Cl-VSLS (chlorine-containing very short-lived substances), including the widely used industrial solvent dichloromethane, have been increasing in abundance since the early 2000s. Understanding where these compounds come from and what they do once they're in the atmosphere is a growing area of scientific concern.

Chlorine in the troposphere interacts with other gases in ways that matter for both climate and air quality. It can influence concentrations of methane — one of the most potent greenhouse gases driving the climate crisis — as well as nitrogen oxides and ozone, both of which affect the air we breathe. These are complex, interacting chemical systems, and small changes in chlorine levels can have cascading effects.

Kathryn's research uses sophisticated computer models to simulate chlorine sources and chemical behaviour in the troposphere. By modelling these processes, scientists can better predict how gases and pollutants will behave under different conditions — and use those predictions to inform strategies for protecting air quality and tackling climate change.

Public Engagement

This animation was commissioned to make tropospheric chlorine chemistry accessible to a general audience, translating complex atmospheric science into clear, visual storytelling without requiring prior knowledge of chemistry or climate science. It is intended for use in public engagement, educational, and conference settings.

This is one of a series of animations produced for Envision PhD researchers. Envision runs a competition in which early-career researchers submit a brief for an animated film; selected winners have their research brought to life through professional animation.