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Low cost sensors for PM and related air pollutants in the US and India
Citation:
Johnson, K., M. Bergin, A. Russell, AND G. Hagler. Low cost sensors for PM and related air pollutants in the US and India. Presented at EPA Air Sensors Conference, Durham, NC, June 09 - 10, 2014.
Impact/Purpose:
This is a poster that will be displayed at the Air Sensors 2014 conference.
Description:
Emerging air quality sensors have a variety of possible applications. If accurate and reliable, they have a number of benefits over conventional monitors. They are low-cost, lightweight, and have low power consumption. Because of their low cost, a dense array of sensors installed in urban areas can be used to better quantify spatial variability. In addition, the fast sensor response time can help better characterize temporal variability in a variety of settings.Cozir CO2 sensors and a variety of Shinyei particle sensors have been evaluated at sites in Atlanta, GA and in Hyderabad, India and have been evaluated against reference instruments. The sensors compared well, following the same trends as the reference instruments, and calibration curves were generated to convert the sensor outputs into concentrations. Using these sensors, data was collected near the freeway in Atlanta for a few days and sensor-derived emissions factors were calculated over morning rush hour, which was about a 1.5 hour period of elevated concentrations. This is especially important since vehicles, fleets, and emissions factors vary regionally especially globally. PM concentrations monitored in the two cities were very different with 1 hour concentrations between 10 and 30 μg m-3 seen in Atlanta near the freeway and 1 hour concentrations between 60 and 260 μg m-3 seen in Hyderabad. Based on the results in these different environments, the optimum concentration ranges of these sensors have been determined. In addition corrections for humidity have been made using humidity sensors. Initial testing shows promising results for these sensors and additional work will be done in China in the coming months.