Research · sources · methodology
The evidence behind the problem statement.
The wider petrol-evaporation context on this website is based on public, authoritative sources. External emission factors and national statistics describe the scale of the problem; they do not prove SPPE performance.
Emission factors
Petrol-storage and dispensing emission factors
US EPA AP-42 identifies separate uncontrolled VOC emission factors for storage-tank breathing, underground-tank filling, vehicle refuelling and spillage. These factors use different scopes and units and must not be treated as a single universal liquid-loss rate.
| Activity | Uncontrolled emission factor |
|---|---|
| Underground-tank breathing or emptying | 120 mg VOC per litre of throughput |
| Submerged underground-tank filling | Approximately 880 mg VOC per litre of throughput |
| Vehicle-refuelling displacement | 1,320 mg VOC per litre dispensed |
| Spillage | 80 mg VOC per litre dispensed |
These are published uncontrolled emission factors, not SPPE performance data. Actual losses vary with fuel, temperature, tank design, turnover and installed controls.
UK context
UK commercial context
Official UK road-fuel statistics describe petrol-sales activity across Great Britain. They establish the scale of petrol throughput but do not, on their own, quantify evaporative loss for a specific site or nationally.
A national monetary estimate is not published here because a robust controlled-scenario methodology is still required.
Such a methodology must separate controlled and uncontrolled emission factors, account for Stage I and Stage II vapour recovery, avoid double counting, and convert vapour mass to liquid volume using petrol density under real UK operating conditions.
Air quality
VOC and air-quality context
UK Government guidance identifies petrol vapour as a source of non-methane volatile organic compounds. VOCs react with nitrogen oxides in sunlight to form ground-level ozone, a principal component of photochemical smog.
Regulation
Existing vapour-control regulation
European Stage I requirements address vapour emissions from petrol storage and distribution. Stage II requirements address vapour recovery during vehicle refuelling at qualifying service stations. SPPE is presented as a complementary prevention-first technology, not a substitute for applicable controls.
Sources
Primary public sources
- US EPA AP-42 §5.2 — Transportation and Marketing of Petroleum Liquids ↗
- US EPA AP-42 Chapter 7.1 — Organic Liquid Storage Tanks ↗
- UK Government — Average road-fuel sales, deliveries and stock levels ↗
- UK Government — Weekly road-fuel prices ↗
- UK Government — Non-methane volatile organic compound emissions ↗
- EMEP/EEA Air Pollutant Emission Inventory Guidebook 2023 ↗
- EU Directive 94/63/EC — Stage I petrol-vapour control ↗
- EU Directive 2009/126/EC — Stage II petrol-vapour recovery ↗
- US EPA — Ground-level ozone basics ↗
Sources last reviewed: 11 July 2026.