A low-energy, filter-less, ozone-free particulate matter (PM) exposure reduction system
designed for long-term, low-maintenance operation in polluted urban environments.
VAAS (Vortex-Adhesion Air Scrubber) is a passive–active hybrid air cleaning system that removes airborne particulate matter (PM10 and PM2.5) using geometry, airflow control, and surface adhesion, rather than disposable filters, ionization, or chemical processes.
The system is designed around a tall vertical column (≈6 ft / 1.8 m) that gently pulls ambient air upward through a helical flow path formed by a flat twisted internal sheet inside a cylindrical outer shell.
Instead of aggressively filtering air, VAAS:
- slows air,
- forces repeated curved trajectories,
- pushes particles into boundary layers,
- and relies on microscale adhesion forces to permanently capture them.
This design prioritizes:
- longevity
- low power
- zero consumables
- visible, verifiable dust capture
- safety (no ozone, no chemicals)
Most air purification systems optimize for instantaneous efficiency at the cost of:
- high pressure drop
- filter replacement
- high energy use
- silent failure when clogged
VAAS instead optimizes for:
Lifetime-integrated particulate removal per watt, per unit of maintenance.
This makes it suitable not just as a gadget, but as infrastructure.
Key principles:
- Continuous operation beats burst performance
- Exposure reduction matters more than city-wide AQI averages
- Predictable failure modes are better than silent ones
- Decade-scale operation matters more than peak efficiency
- Height: ~6 ft (1.8 m)
- Diameter: 30–40 cm (recommended)
- Orientation: Vertical
- Flow direction: Bottom → Top (pulled by fans)
- A flat sheet twisted helically around the central axis
- Typical total twist: 360°–540°
- Pitch chosen to avoid flow choking while maximizing near-wall exposure
- Cylindrical outer tube
- One side may be transparent for inspection and documentation
- Internal surfaces backed by rigid material (metal or polymer)
- Low-speed axial fans mounted at the top
- Fans operate in pull configuration (negative pressure)
- Typical airflow: 50–150 m³/h depending on scale and fan choice
- Power: ~5–10 W per unit
VAAS relies on stacked weak physical effects rather than a single strong mechanism.
Air follows curved streamlines easily; particles do not.
When airflow bends around the twisted sheet:
- particles lag behind due to inertia
- heavier particles (PM10) deviate more strongly
- lighter particles (PM2.5) deviate probabilistically
This causes particles to drift toward surfaces.
Helical motion introduces centrifugal acceleration:
[ a_c = \frac{v^2}{r} ]
Even at low velocities (≈0.3–0.8 m/s), repeated curvature causes particles to migrate outward toward walls.
Near any solid surface:
- air velocity drops toward zero
- turbulence collapses
- particles entering this region lose escape energy
Once in the boundary layer, particles are far more likely to impact and stick.
Once a particle contacts a surface, airflow physics largely stops mattering.
Dominant forces:
- Van der Waals attraction
- Electrostatic polarization (even without active charging)
- Mechanical interlocking with surface roughness or fibers
At micron scales, these forces exceed aerodynamic lift at VAAS operating velocities.
This is why:
- dust sticks to walls,
- buildings blacken over time,
- filters work without glue.
VAAS does not rely on 100% capture per pass.
If the probability of capture per interaction is p, and the number of interactions is n:
[ P_{\text{capture}} = 1 - (1 - p)^n ]
With:
- low per-pass probability
- many forced interactions
Capture becomes statistically inevitable.
Particles remain attached because:
- adhesion forces dominate at small scales
- airflow velocity near surfaces is low
- no sharp pressure gradients exist to re-entrain them
Re-entrainment occurs only if:
- air velocity is very high
- vibration occurs during airflow
- surfaces are extremely smooth
VAAS is designed to avoid all three.
- Airflow: 80–120 m³/h
- Average air velocity: 0.3–0.6 m/s
- Residence time: 2–4 seconds
- Power consumption: 5–10 W
- PM10: ~70–90%
- PM2.5: ~40–60%
Efficiency improves with:
- greater height
- more total twist
- lower velocity
- rougher surfaces
Assuming:
- Total PM concentration ≈ 300 µg/m³
- Air processed ≈ 2,000–3,000 m³/day
- Weighted capture efficiency ≈ 55%
Dust captured:
≈ 0.8–1.5 grams per day per unit
This is physically verifiable by mass accumulation.
VAAS is not intended to significantly change city-wide AQI values.
Instead, it targets human exposure at:
- bus stops
- stations
- building interiors
- confined or recirculating spaces
Local reductions of 30–60% in PM concentration within the exhaust plume are realistic and medically meaningful, even if city AQI remains unchanged.
- High instantaneous efficiency
- High pressure drop
- Frequent filter replacement
- Poor outdoor longevity
- Moderate efficiency
- Electrode degradation
- Ozone risk
- Regulatory complexity
- Temporary suppression
- No permanent PM removal
- High water and maintenance cost
- Moderate efficiency
- No consumables
- No ozone
- Visible, measurable capture
- Decade-scale operation
VAAS is designed for forgiving maintenance, not precision servicing.
- Gradual surface loading
- Performance degrades slowly, not suddenly
- Periodic low-frequency structural vibration
- Fans OFF during shedding
- Dust falls into bottom tray
- Outdoor: monthly or quarterly
- Indoor: quarterly or longer
No filters. No disposables.
- No high voltage
- No ionization
- No ozone generation
- No chemical byproducts
- Low noise
- Low temperature rise
Suitable for continuous operation in public or residential environments.
VAAS scales by replication, not by brute force.
Examples:
- Multiple units at transit choke points
- One unit per building shaft or atrium
- Distributed exposure reduction instead of centralized megastructures
At scale, the system becomes a background environmental service, similar to ventilation or drainage.
VAAS will NOT:
- instantly clean open outdoor air
- replace emission controls
- eliminate the need for policy
- achieve HEPA-level single-pass efficiency
VAAS IS:
- a sustainable exposure reduction layer
- a long-life infrastructure component
- a complement to source reduction, not a substitute
This repository exists to:
- document the physics and engineering
- enable replication and improvement
- invite critique and validation
- support pilot deployments and research
It is not a finished product.
Current status:
- Full-scale prototype under construction
- Sensor-less validation via mass accumulation and optical visualization
- Long-duration runtime testing underway
Future work:
- Indoor building-scale trials
- Long-term fouling characterization
- Comparative lifecycle cost analysis vs HEPA
This project prioritizes:
- public health
- scientific honesty
- low-resource applicability
- long-term sustainability
Commercialization, if any, should preserve these principles.
VAAS is not a silver bullet.
It is a quiet, persistent intervention that works with physics instead of fighting it.
That is its strength.