A Low-Cost Sensor System Installed in Buses to Monitor Air Quality in Cities

Area of Science:

• Environmental Science
• Public Health
• Sensor Technology

Background:

• Air pollution significantly impacts public health, necessitating accurate exposure assessments, especially in urban environments.
• Low-cost sensors offer a promising solution for real-time air quality (AQ) data collection, but require rigorous quality control.
• The ExpoLIS system integrates mobile sensor nodes and a routing app to provide personalized exposure information to commuters.

Purpose of the Study:

• To evaluate the reliability and performance of the ExpoLIS system for real-time air quality monitoring.
• To assess the accuracy of the Alphasense OPC-N3 particulate matter sensor under laboratory and field conditions.
• To demonstrate the utility of the ExpoLIS system in generating high-resolution AQ maps and a Health Optimal Routing Service App.

Main Methods:

• Laboratory evaluation of the Alphasense OPC-N3 particulate matter sensor under controlled temperature and humidity.
• Field validation at an air quality monitoring station, comparing sensor data against reference equipment.
• Application of k-Köhler theory and Multiple Regression Analysis for sensor data correction and improved accuracy.

Main Results:

• The particulate matter sensor demonstrated excellent correlation (R²≈1) with reference equipment in laboratory settings.
• Initial data from the monitoring station showed dispersion, which was significantly reduced after applying correction methods.
• The validated ExpoLIS system successfully generated high spatial and temporal resolution AQ maps.

Conclusions:

• The ExpoLIS system, after calibration and data correction, provides a reliable method for real-time air quality assessment.
• The integrated Health Optimal Routing Service App is a valuable tool for informing commuters about their exposure to air pollution.
• Mobile low-cost sensor networks can enhance urban air quality monitoring and public health initiatives.