The transportation company partnered with Trinity Consultants, leveraging Trinity’s extensive experience in environmental compliance and air quality monitoring, to design and implement the new plan. Trinity’s system included two Federal Equivalent Method (FEM) monitors and eight low-cost sensors at various points along the fence line, to comprise a Quality Assurance Project Plan (QAPP). The strategic positioning and novel combination of high-precision monitors and supplemental sensors allowed the system to accurately capture data for both inbound and outbound wind scenarios, providing a complete picture of PM emissions under varying atmospheric conditions.

Trinity also installed a 10-meter (approximately 33 feet) meteorological tower equipped to measure wind speed, wind direction, humidity, temperature, barometric pressure, and precipitation. The data collected is critical for interpreting the PM monitoring results, which would help Trinity and the company understand the source and movement of PM detected by the system. For instance, wind speed and direction data could be used to trace the origin of dust plumes (whether from the facility or from other regional sources), while wind speed and precipitation data are used to determine when to activate dust suppression measures on storage piles. Trinity also addressed technical challenges related to data accuracy. Low-cost sensors are less robust, and tend to report erroneous data during fog, high humidity, or precipitation events. To mitigate this, Trinity developed testing factors in conjunction with meteorological data to flag potential false positives, ensuring the integrity of the monitoring system.