Every Breath You Take: The Real Cost of Air Pollution
Dr Rebecca Drury, Nicky Amos and Dr Rory Sullivan
Chronos has partnered with ShareAction to explore the environmental, human health and financial implications of diminishing air quality.
Exposure to outdoor air pollution is now the largest environmental threat to human health globally. Over 99% of people live in areas exceeding WHO air quality guidelines. Ambient air pollution causes 6.7 million premature deaths each year, with global health costs of $6 trillion annually. Fine particulate matter (PM2.5) — tiny particles less than 2.5 micrometres in diameter that can penetrate deep into the lungs and enter the bloodstream – are responsible for over 90% of these deaths.
Air quality has received relatively little attention from investors in recent years. Chronos was, therefore delighted to partner with ShareAction to produce an investor briefing on air quality. From the issue’s connection with wider nature loss to implications for climate and human rights, we offer some key reflections from our research:
Investors need to ensure that air emissions and air quality are integral parts of their strategy on nature: Air pollution is a major driver of nature loss, yet its full impacts on nature are systematically under-accounted for in policy, business and investment decision-making. Focusing solely on the medium to which pollutants are emitted inevitably understates their true impacts: airborne pollutants ultimately are inhaled by humans, are deposited onto soil and vegetation, and deposited or discharged into rivers and the ocean. That is, they exacerbate water and soil pollution, which means that they have multiple pathways into the food chain.
Applying a systems approach recognises these interconnections and supports integrated management of risks spanning climate, health and human rights: A nature lens frames air pollution as a systemic driver of nature loss, and recognises that pollutants move across air, land and water, accumulate in ecosystems, and in turn harm both biodiversity and human health. This systems perspective is essential to identifying related risks, feedback loops and co‑benefits across climate, nature, health and human rights that are missed by a more siloed approach.
Decarbonisation does reduce air pollution, but decarbonisation alone will not address emissions of particulate matter, with serious consequences for public and ecosystem health: To provide just one example, in the coming years, emissions from tyre and brake wear are expected to be responsible for most PM (particulate matter) emissions from road transport. Tyre abrasion is already the largest contributor (>35%) to microplastic emissions across air, water and soil. Around 30% of brake wear particles have been found in the ocean. These particles are a disproportionately toxic form of PM. As well as causing severe human health impacts, they leach chemicals implicated in the sudden deaths of up to 90% of salmon in urban streams in the northwestern United States.
The business and financial risks and opportunities of air quality are rising: In response to rising health costs, air pollution regulation is strengthening globally. At the same time, regulators appear increasingly willing to enforce air quality legislation, and to press for large fines and penalties on those companies that are convicted of breaching this legislation. For example, in the United States, Hino Motors was fined $1.6 billion in 2025 for fraudulent emissions testing under the Clean Air Act. We are also seeing economic opportunities. For example, companies are starting to invest in low-emission and emissions capture technologies, smart transportation systems, and greener chemistry in manufacturing.
So where does this leave us?
The ShareAction briefing suggests that investors need to be more aware of the risks and opportunities connected with rising air pollution, recommending that investors should:
Identify their exposure to high-risk sectors - using tools such as the Exploring Natural Capital Opportunities Risks and Exposure (ENCORE) database or Science-based Targets Network (SBTN) materiality screening tool.
Integrate these findings into investment decision-making - including valuations, portfolio construction and capital allocation.
Engage to drive improvement - encouraging companies to monitor and disclose their air pollutant emissions, and to adopt robust air pollution management systems and reduction plans.
Support innovation in low-emission technologies - such as non-exhaust emissions (NEEs) mitigation, green chemistry approaches, in alignment with regulation and societal needs.
The Chronos’ view:
This is an extremely important and timely report. Given that many investors have, in recent years, built their capacity and expertise on nature, many will already have the systems and processes they need to integrate air quality into their investment decision-making and their engagement with companies.
In doing so, investors can get ahead of the curve on global regulation on this issue and support the delivery of positive outcomes for biodiversity and for public health. Recognising these connections is essential for building resilient and effective responses. The ShareAction report provides an extremely useful basis for these efforts.
You can read the full briefing here.
To find out more contact: Rebecca Drury, Biodiversity and Nature Manager
