20 10 School of Electrical Engineering &Telecommunications UNSW UNSW 10 Author: James Carrapetta Supervisor: Dr Vijay Sivaraman Wireless Sensor Board for Measuring Air Pollution Introduction Fresh breathing air has always been a basic requirement for human beings, however with current global trends we are beginning to lose this most basic privilege. Air Pollution: Is responsible for 2.3% of Australian deaths each year and costs the government of NSW an estimated $4.7billion per year in health costs. Is the cause of more premature deaths in NSW each year than car accidents Has the potential to cause adverse health effects including: Respiratory Infections Heart Disease Lung Cancer Current air quality monitoring systems are expensive and far apart. With a more detailed recording and monitoring system for air pollution, significant improvements can be made to the general population’s health and well being. Concept 1. Mobile Sensor: measures air pollution while the user drives 2. Smart Phone: uploads samples via 3G network to server 3. Database server: stores and uses pollution data to produce a pollution model for applications 4. Web interface: overlays pollution map and displays on Google maps Wireless Sensor Board The wireless sensor board is completely mobile and can be easily attached to the exterior of a car. The whole device only measures 70mm x 120mm and takes air pollution samples every 15 seconds. The wireless sensor board can measure: Carbon Monoxide Nitrogen Dioxide Ozone Using Bluetooth these measurements are sent to a Smart Phone within the car where both time and GPS coordinates are recorded. These recordings are then sent to a server via the 3G network. The wireless sensor board has been carefully designed to allow production of multiple units, each uniquely identified. Results Sensors The wireless sensor board uses metal oxide semiconductor gas sensors. A semiconductor material is heated and when a gaseous pollutant is introduced into the chamber, electrons are freed from the semiconductor. This decreases its effective resistance proportional to the level of pollution. By measuring the voltage at the output of the sensor, an air pollution reading can be estimated. Theses sensors are low cost, small and require a simple external measuring circuit. The wireless sensor board was attached externally to a car with a commercially available GasAlertMicro 5 air monitor. The car was then taken for a drive from Mosman across Sydney to Padstow. Carbon Monoxide was measured by both devices and then compared to approximations based on government monitoring sites (red markers). The wireless sensor board produced similar results to the commercially available air monitor. When compared with the estimation from the available government data, both devices showed that the air pollution varies significantly between close locations. This supports the need for a more detailed, mobile air monitoring system examining pollution levels at more locations. Conclusion Currently the government has 12 fixed air monitoring stations around Sydney, too few to accurately measure pollution levels across Sydney. With the wireless sensor board in use, a more precise air monitoring system can be used for various applications. With this new system in action we can begin to take the first steps to an improved and healthier world.