Low-Cost Particle Counter Sensor Assessment of the July 2018 Saharan Dust Event in Texas

There is a growing community of scientists, research students, science enthusiasts, and K-12 STEM students who are developing and testing low-cost, ultraportable air quality sensors. The sensors can share the data publicly and be validated by using standardized ground- and space-based platforms as ground-truth. Two particle sensor packages (Grove and Waveshare) were developed and tested using a newly obtained Sigma Space Micropulse Lidar (MPL) at Texas A&M University (College Station, TX) for data validation. Several hours after being installed and powered for the first time in early July 2018, a well-defined large Saharan dust plume entered Texas from the southeast. The MPL showed that most of the dust was confined to the lowest 2-3 km of the troposphere and correspondingly, visibility and air quality deteriorated along the areas in the direct path of the plume. The sensors indicated a fluctuating pattern of particulate concentration that coincided with the diurnal cycle of the boundary layer as observed by the MPL (e.g., local aerosols from morning traffic and University construction). Included in the sensor package are sensors to measure temperature, pressure, and humidity which also showed a diurnal pattern that was validated by the local ASOS (Easterwood Airport, College Station, TX). Northerly and easterly wind patterns resulted in decreased aerosol concentrations by the sensor package which was also validated by the MPL. Though the sensor package suffers from data quality issues, the trends in meteorology and aerosol concentrations are in good agreement with the ground-truth platforms and therefore, should be further improved and tested in future undergraduate research and K-12 STEM projects.