High-Density, High-Resolution, Low-Cost Air Quality Sensor Networks for Urban Air Monitoring. The SNAQ Heathrow Project

Monitoring air quality in highly granular environments such as urban areas which are spatially heterogeneous with variable emission sources, measurements need to be made at appropriate spatial and temporal scales. Current routine air quality monitoring networks generally are either composed of sparse expensive installations (incorporating e.g. chemiluminescence instruments) or higher density low time resolution systems (e.g. NO2 diffusion tubes). Either approach may not accurately capture important effects such as pollutant “hot spots” or adequately capture spatial (or temporal) variability. As a result, analysis based on data from traditional low spatial resolution networks, such as personal exposure, may be inaccurate. A state of the art multi species instrument package for deployment in scalable sensor networks has been developed which has general applicability. This is a a sophisticated, low-cost, multi species (gas phase, speciated PM, meteorology) air quality measurement network methodology incorporating GPS and GPRS which has been developed for high resolution air quality measurements in urban areas. This is currently being employed as part of a major 3 year UK program at London Heathrow airport (Sensor Networks for Air Quality (SNAQ)). The main project outcome is the creation of a calibrated, high spatial and temporal resolution data set. The network incorporates existing GPRS infrastructures for real time sending of data with low overheads in terms of cost, effort and installation.