Funding focused on super pollutants

Super pollutant abatement offers a fast track to cleaner air

Super pollutants are a grouping of atmospheric pollutants that have climate effects greater than carbon dioxide (CO₂) and can have environmental and human health effects. Their contribution to global warming is between 39% and 59%.¹ The air pollution caused by many super pollutants also to leads to millions of premature deaths each year.²

Unlike carbon dioxide, which lingers in the atmosphere for centuries, many super pollutants are short-lived. That means reducing them can lead to immediate improvements in air quality and slow down global warming.

Black carbon

Projects with emission-reducing co-benefits drive black carbon funding

Reducing black carbon delivers rapid improvements in air quality and public health by lowering exposure to fine particulate matter, while also slowing near-term warming.

Primary black carbon funding – where black carbon reduction is an explicit project objective – accounted for 0.1% of total black carbon funding in 2020-2024, with only one project in 2024. This scarcity of primary funding indicates a lack of explicit targeting of black carbon across international development finance.

Instead, 99.9% of tracked black carbon funding delivers reductions as a co-benefit. This secondary funding targets major black carbon-emitting activities or sources without explicitly targeting black carbon – for example, replacing diesel buses with electric fleets. Secondary black carbon funding grew from $1.2 billion in 2020 to $7.5 billion in 2024, increasing from 8% to 26% of all air quality funding (see table above).³ The growth suggests that investments targeting black carbon-emitting sources are increasingly delivering black carbon reductions as a co-benefit. There is great potential to leverage investment in related development and climate objectives to deliver black carbon reductions at scale.

Tropospheric ozone

Tropospheric ozone remains largely overlooked by international development funders

Super pollutant abatement is not leading to increased funding for reducing tropospheric ozone precursors.

This report tracks and analyses international development funding committed to the abatement of tropospheric ozone precursors for the first time. Tropospheric ozone contributes to respiratory illness and premature mortality, while acting as a short-lived greenhouse gas that contributes to near-term warming and damages crop productivity.⁴ Rather than being emitted directly, it forms in the atmosphere through sunlight-driven chemical reactions involving precursor pollutants, including nitrogen oxides, volatile organic compounds, carbon monoxide, and methane. Tropospheric ozone concentrations are therefore reduced indirectly by controlling emissions of its precursors.

Funding for tropospheric ozone abatement reached just $111 million in 2024 (see table below), equivalent to 0.4% of total air quality funding. In 2024, all of this finance was secondary funding, addressing emissions of its precursor pollutants without explicitly identifying tropospheric ozone reduction as an objective. Similarly, only negligible amounts of primary funding that explicitly target the reduction of tropospheric ozone were tracked across 2020-2024. This suggests that, despite the strong climate, health and air quality rationale for reducing tropospheric ozone, it remains largely absent as an explicit objective of international development finance. Funders should target ozone precursors based on local understanding of ozone formation to avoid the risk of unintended increases in ozone, and combine interventions with monitoring.⁵

Notes and references

¹G.B. Dreyfus, Y. Xu, D.T. Shindell, D. Zaelke, & V. Ramanathan. 2022. Mitigating climate disruption in time: A self-consistent approach for avoiding both near-term and long-term global warming.

²UNEP. Meet the super pollutants

³Black carbon funding estimates are not directly comparable with previous editions of this report. The substantial increase reported in 2026 primarily reflects a methodological expansion of the black carbon taxonomy to capture a broader range of relevant activities, and to align the analysis more closely with development finance institution terminology, as detailed in the report methodology.

⁴UNEP. 2021. A Tale of Two Ozones

⁵In some environments, for example, reducing NOx will decrease ozone, but in others, this reduction in NOx can paradoxically increase ozone. The relationship between precursors can change over time and vary between relatively small areas – different areas of the same city might experience ozone levels driven by different mixes of precursors. Source: Clean Air Fund. (2025). Accelerating Action on Tropospheric Ozone: A Strategic Roadmap for 2025-2030.