Technology

Smart city infrastructure.
At street level.

Every Clean Air Initiative lamppost is simultaneously an air-cleaning unit, a pollution monitoring station, a public WiFi node, and a smart city data asset. Here is the full technology specification.

Sensor Suite

Real-time data at
breathing height.

Unlike rooftop monitoring stations, Clean Air Initiative sensors are positioned at 1–2 metres above pavement — the height where people actually breathe. Every post is a real-time environmental monitoring station.

🟡
NO₂ Sensor
Electrochemical sensor measuring nitrogen dioxide concentration in real time. Temperature and humidity compensated. Calibrated against LAQN reference monitors at installation.
Range: 0–2,000 ppb
±5 ppb accuracy
T90 <60 seconds
Continuous
🔵
PM2.5 / PM10 Sensor
Optical particle counter measuring fine and coarse particulate matter simultaneously. Omnidirectional inlet captures ambient street-level air, not filter exhaust.
Range: 0–1,000 μg/m³
±10% accuracy
PM2.5 + PM10
6 size bins
🌡
Temperature & Humidity
Combined capacitive humidity sensor and platinum resistance thermometer. Provides environmental context for pollution readings and contributes to local microclimate data.
±0.5°C accuracy
±3% RH humidity
−20°C to +70°C range
💨
Wind Speed & Direction
Ultrasonic anemometer — no moving parts, no maintenance. Mounted on Primary Node posts (every 5th in a corridor). Wind data improves pollution dispersion modelling and fan speed optimisation.
0–60 m/s range
±0.1 m/s accuracy
Primary nodes only
Heated for winter
⚡
Power Monitor
Real-time measurement of grid draw and solar film generation per post. Used for energy reporting, efficiency monitoring, and fault detection. CT-based, non-invasive installation.
Grid draw (W)
Solar generation (W)
Energy (kWh)
Fault detection
🔧
Filter Status Sensor
Differential pressure sensor across the filter stack. Monitors filter loading as pressure drop increases with particle capture. Triggers maintenance alert when replacement threshold is reached.
0–500 Pa range
±5 Pa accuracy
Auto replacement alert
Public Dashboard

Transparency by design.

All sensor data from every Clean Air Initiative post feeds a real-time public dashboard — accessible to anyone. Before and after comparisons, live street-level maps, and open data downloads.

Clean Air Initiative · Live Dashboard
Live · Updated 30s
34
Active posts · Brixton Road
847k
m³ air processed today
−18%
PM2.5 vs baseline (this week)
−12%
NO₂ vs baseline (this week)
NO₂ concentration · Brixton Road · Last 24 hours
00:00 06:00 12:00 18:00 Now Baseline (before) Current (after)
Brixton Road N · Posts 1–12
NO₂: 28 ppb · PM2.5: 8 μg/m³ · Good
Brixton Road S · Posts 13–24
NO₂: 31 ppb · PM2.5: 10 μg/m³ · Good
Brixton Road Jcn · Posts 25–34
NO₂: 44 ppb · PM2.5: 14 μg/m³ · Moderate
Network uptime
34/34 posts active · 99.8% uptime this month
Technology Stack

Built for scale
from day one.

The software and data infrastructure underpinning the Clean Air Initiative is designed to handle millions of posts, real-time data streams, and a public-facing dashboard with global access.

🔧
Unit Controller
Linux-based single-board computer managing sensor data acquisition, fan speed control, Starlink data transmission, and over-the-air firmware updates. Watchdog timer for automatic restart. 24-hour local data buffering.
LinuxARM CortexMQTTOTA Updates
☁️
Cloud Data Platform
AWS-hosted microservices architecture. MQTT broker for sensor data ingest. Time-series database for full-resolution storage (2 years) with aggregated data retained indefinitely. REST API for dashboard and data licensing.
AWSInfluxDBMQTTREST API
📊
Public Dashboard
Progressive Web App accessible on any device without installation. Real-time interactive map with colour-coded pollution levels. Before/after comparison tools. Open data download in CSV format. Creative Commons CC-BY licence.
React PWAMapboxReal-timeOpen Data
🛰
Starlink Integration
Starlink Mini terminal concealed within the upgraded light head (same external appearance). RF-transparent polycarbonate panel maintains satellite signal. BLE mesh connects secondary nodes to the Primary Node. 1Gbps Ethernet interface to unit controller.
Starlink MiniBLE Mesh1GbpsUK Coverage
🔐
Security & Privacy
All sensor data is environmental — no personal data collected. Public WiFi usage anonymised. UK GDPR compliant from day one. API authentication via JWT. Field unit communication encrypted in transit. ICO registered.
UK GDPRJWT AuthEncryptedICO Registered
📡
Remote Management
Full remote management via Starlink connection — OTA firmware updates, fan speed commands, alert configuration, and unit commissioning. Automated alerts for fault conditions with 4-hour response SLA for safety-related issues.
OTARemote ConfigAuto Alerts24/7 Monitor