Continuous PM₁₀ Monitoring in High-Dust Environments

Coarse particulate matter (PM₁₀) is a serious and persistent local air quality concern in the Coachella Valley. The Twenty-Nine Palms Band of Mission Indians plans to expand PM₁₀ monitoring across the region to supplement existing regulatory monitoring infrastructure in a cost-efficient manner and better inform the community about PM₁₀ exposure. They chose to evaluate the MODULAIR-PM to (1) determine its ability to provide continuous, reliable measurements in a harsh, high-dust environment and to (2) determine its durability over an extended period of time.

High dust environments pose a number of monitoring challenges

The Coachella Valley often experiences periods with elevated PM₁₀ levels due to wind-blown dust in the arid Colorado desert. The air quality monitoring team at the Twenty-Nine Palms Band of Mission Indians needed a lower-cost alternative to supplement their existing regulatory monitoring infrastructure throughout the community. They needed something that was small, accurate, easy to use, internet-connected with minimal maintenance required, and economically feasible. The team has previous experience deploying other lower-cost devices but found the majority suffer from a lack of sensitivity to PM₁₀, especially during high wind conditions.

MODULAIR-PM provides accurate PM₁₀ data over extended periods of time

Throughout the evaluation period (229 days), hourly PM₁₀ levels regularly exceeded 500 µgm^-3, reaching as high as 3,000 µgm^-3. The MODULAIR-PM exceeded expectations for uptime (99.5%) relative to the T640X (93.3%), with zero downtime for maintenance or calibration.

Hourly and 24-h PM₁₀ data showed a high correlation with the EPA FEM equivalent (Teledyne T640X) with a coefficient of determination of 0.75. The mean absolute error was shown to be 12.5 µgm^-3 with a mean bias of -24%. Throughout the nearly eight-month evaluation period, the MODULAIR-PM shows no sign of a decrease in sensitivity, despite PM₁₀ loadings that regularly exceed the World Health Organization (WHO) air quality guideline for 24-hour mean PM₁₀ of 45 µgm^-3. These results show the MODULAIR-PM exceeds the EPA Air Sensor Guidebook's (2018) requirement for hotspot identification and characterization.

Overall, the MODULAIR-PM was shown to be a reliable device for making continuous PM₁₀ measurements in a harsh environment, even under high wind conditions. The combination of robust hardware, no maintenance requirements, and access to real-time data via the QuantAQ Cloud will allow the Twenty-Nine Palms Band of Mission Indians to confidently scale their monitoring efforts across the Coachella Valley in a cost-effective manner.

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QuantAQ develops internet-connected professional-grade air quality sensors for indoor and outdoor air quality monitoring applications. Developed at MIT and Aerodyne Research, QuantAQ's core technology is vetted and verified through peer-reviewed papers and trusted by top research institutions across the world.