Air Quality Health Units (AQHUs)¶
The First Tradable Health Benefit Asset for Port Pollution Reduction¶
Key Concept
1 AQHU = 1 Disability-Adjusted Life Year (DALY) avoided through verified reduction in port-attributable air pollution exposure.
The Problem¶
Carbon credit methodologies quantify greenhouse gas reductions. They do not capture the health co-benefits of emissions reduction — even when those health benefits are orders of magnitude larger than the carbon value.
At a port, a barge-mounted capture system that removes 99% of PM2.5 and 95% of NOx simultaneously prevents premature deaths, hospitalizations, and asthma attacks in surrounding communities. These health benefits are real, measurable, and monetizable — but they currently have no market mechanism.
Verra's SD VISta program currently has only one approved asset methodology (time savings from cookstoves). No methodology exists for air quality health benefits from any source, let alone port emissions. This is an open field.
The Framework¶
Air Quality Health Units (AQHUs) are being developed for submission to Verra's SD VISta program, which certifies Sustainable Development contributions aligned with the UN Sustainable Development Goals.
Quantification Process¶
Step 1 — Measure: Emissions captured per vessel-hour using verified monitoring data from the capture system. PM2.5 and NOx mass removed, independently measured.
Step 2 — Model: Concentration reduction in surrounding communities using EPA-standard dispersion modeling (InMAP or BenMAP). Two approaches supported:
- Approach A (Preferred): Site-specific dispersion modeling using monitored emissions data and local meteorology
- Approach B (Screening): Transfer coefficients from ICCT goPEIT screening data, calibrated with EPA InMAP reduced-complexity modeling
Step 3 — Quantify: Translate concentration reductions into avoided DALYs using:
- Peer-reviewed concentration-response functions (Krewski et al. 2009; Lepeule et al. 2012)
- WHO disability weight tables for PM2.5-attributable disease endpoints
- Local baseline health outcome rates from state/county health departments
- Exposed population counts from U.S. Census at census tract resolution
Step 4 — Verify: Independent third-party validation of each step, producing verified AQHUs eligible for registration under SD VISta.
SDG Alignment¶
AQHUs directly support three UN Sustainable Development Goals:
- SDG 3 (Good Health and Well-Being): Quantified reduction in premature mortality and respiratory disease
- SDG 10 (Reduced Inequalities): Health benefits concentrated in low-income communities and communities of color bearing disproportionate pollution burden
- SDG 11 (Sustainable Cities and Communities): Measurably cleaner air in urban port neighborhoods
The Stacked Revenue Model¶
AQHUs create a stacked revenue model when combined with carbon credits from the same capture operation. A single barge treating vessel exhaust generates three distinct revenue streams:
| Asset Class | Source | Market |
|---|---|---|
| VCUs (Verified Carbon Units) | CO2 captured and mineralized | Verra VCS voluntary carbon market |
| SD VISta Label on VCUs | Quantified health and SDG co-benefits | 30–100% price premium over unlabeled VCUs |
| AQHUs (Air Quality Health Units) | PM2.5 and NOx reduction, measured in avoided DALYs | New asset class — SD VISta health benefit market |
All three revenue streams derive from the same capital deployment: the same barge, the same operating hour, the same exhaust stream. This stacking is what makes the economics work for deployment at non-regulated ports where there is no compliance mandate to drive demand.
Market Sizing¶
| Timeframe | Barge Fleet | Estimated AQHU Revenue |
|---|---|---|
| 2030 (80 barges) | California + early East Coast / UK | $5M–$50M/year |
| 2035 (500 barges) | Multi-port US + international | $50M–$563M/year |
| 2040 (2,000+ barges) | Global fleet | $500M–$4.5B/year |
These projections assume AQHU pricing based on DALY valuation literature ($500–$5,000 per avoided DALY) and conservative capture efficiency and dispersion assumptions. Actual pricing will depend on market development, buyer demand, and SD VISta program parameters.
Why This Matters for Communities¶
For port-adjacent communities, AQHUs represent something new: a financial mechanism that directly values their health. Currently, the health costs of port pollution are externalities — borne by communities, invisible in the economics of shipping. AQHUs internalize those costs by creating a market for their avoidance.
A port authority or shipping company deploying at-berth capture generates AQHUs proportional to the health benefit delivered to surrounding communities. This creates a direct financial link between investment in emissions control and the health outcomes of the people who breathe the air.
Status¶
The AQHU framework is currently in concept development, with formal submission to Verra's SD VISta program targeted for Q4 2026. The concept note draws on the health impact quantification methodology detailed in our Methodology section and demonstrated in our NY/NJ port assessment.
For research collaboration, early access to the methodology framework, or community partnership inquiries, contact us.