Research Instruments

GeoAir2.0 integrates a PM2.5 sensor (SPS30, Sensirion, Stäfa, Switzerland), GPS module, temperature/humidity sensor, data logger, LCD screen, and a battery that lasts up to 15 hours. It is portable/wearable using a belt clip, carabiner, or shoulder strap. It records PM2.5 measurements (μg/m3) every minute, as well as GPS locations, a list of nearby Wi-Fi media access control (MAC) addresses for indoor geolocation, temperature, humidity, date, time, and more. Data are stored locally as an encrypted file for data confidentiality. 

GeoAir2.0 is suitable for citizen-engaged research and geospatial assessments of personal exposure due to its ease of use and ability to track user locations. It does not require a connection to a local Wi-Fi network or technical proficiency from users to record and view data due to an internal data logging capacity and display screen. GeoAir2.0 can be used by all citizens and is widely applicable in many fields, including environmental justice and health disparity research.

Several laboratory and field evaluations have demonstrated its high accuracy and reliability when compared to reference instruments (Park et al. 2022; Streuber et al. 2022; Sousan et al. 2021). 

It was designed by Yoo Min Park and Kai Zhao; prototyped and manufactured by Jaycon Systems (Palm Bay, FL). The software was developed by Kai Zhao and has been constantly updated (currently, v.4). The detailed specifications of GeoAir2.0 and a full list of data recorded by it are described in Park et al. 2022.

Application example of GeoAir2

GeoAir1.0 is a GPS-enabled, portable DIY air monitor developed for health/medical geography education. With GeoAir1.0, students can collect real-time personal air sampling, GPS location, temperature, and humidity data.

GeoAir was designed using a development kit created by M5Stack (Shenzhen, China), powered by an ESP32 core. It consists of multiple stackable M5Stack products, including a basic core (microcontroller) with an LED display; a particulate-matter (PM) sensor base integrated with PMSA003 (a PM sensor developed by Plantower, Beijing, China) and SHT20 (a humidity and temperature sensor); a GPS module; and a 700 mAh lithium-ion polymer battery. Sensor performance was tested by previous studies, and the results demonstrated its high precision and acceptable accuracy (Badura et al., 2020; Levy Zamora et al., 2019; Zusman et al., 2020). 

Several features make GeoAir an ideal educational tool for health geography. First, its portability and built-in GPS enable students to collect georeferenced air-pollution measurements at any location and time for subsequent geographic mapping and analyses and to test their hypotheses about air-pollution hot spots. These features also help students to identify possible sources of air pollution and of GPS errors in the field. Second, the built-in data logger (a micro SD card) enables students to easily transfer the data from the device to their personal computer for data visualization and analysis. Third, the LED display enables students to easily check the air quality in the field, and identify how PM concentrations vary significantly over space and time, while moving through multiple indoor and outdoor environments during data collection. Lastly, GeoAir is very easy to build (i.e., simply by stacking M5Stack modules with a little soldering); therefore, instructors with no electronic skill or knowledge can easily replicate it (open-source GeoAir software and instructions for making the hardware are available).

It was designed and developed by Yoo Min Park and Kai Zhao.

Application example of GeoAir1