Issue link: https://www.e-digitaleditions.com/i/1187394
A L M O N D O R C H A R D 2 0 2 5 G O A L S HARVEST DUST 3 "We were looking to develop some simple methods for growers to measure dust when they're harvesting," Capareda explained. "We also tried to assess field operations by adjustments to machinery as well as using new machinery." Last fall, Capareda and his team went to grower Dan Visser's 120-acre almond orchard in Dinuba to quantify visible dust, or total suspended particulate (TSP), reductions using four methods: f Visually by specialists trained in the federal Environmental Protection Agency (EPA) Method 9 Visual Emissions Evaluation f EPA Alt Method 082 Digital Camera Opacity Technique (DCOT) using digital cameras or video recorders f Opacity meters, which measure the density of dust clouds f A PM sampler installed on drones flying above orchards to measure TSP concentrations "We were also trying different equipment (low-dust and conventional) and different harvesting techniques to answer the question, 'Can we reduce that number compared to previous activities?'" Capareda said. The team gathered opacity readings of the dust generated in order to compare each method on a consistent scale. Opacity readings are measured on a scale of 0 to 100. The highest number, 100, represents a cloud, say of coal dust, where nothing can be seen through it. The lowest reading, 0, would occur in the instance of a clear blue sky. In the case of dust during harvest, Capareda said opacity readings often are 20 or more. The long-term goal is to cut that to 12.5 or less. Here's how the four measurement methods stacked up: The EPA Method 9, or the "eyeball test," is the formal method of what farmers may practice by intuition. In this case, visual readings must be conducted by growers or others who have been certified by the EPA. Those who want to be EPA Method 9 certified must receive training each year to keep up their certification, which may act as a challenge for growers who don't have the time or resources to receive certification each year. Still, numerous certified private companies are available to help growers evaluate dust reductions using this method. Visual estimates of opacity (EPA Method 9) typically come in slightly lower than estimates gathered via EPA Alt Method 082, which allows for the use of digital cameras or recorders. This equipment, however, must also be certified by the EPA, and those using this method must send the data gathered through digital devices to a lab in Denver, which conducts the analysis and provides results in a few days. The team's testing of the third method, opacity meters, showed they don't make sense for growers. "The meters are stationed one row over from where harvesting equipment is active and must continually be moved as harvest progresses. They're just not practical," Capareda said. Finally, the research team tested the measurement efficacy of drones with installed PM samplers flown above orchards during harvest. According to Capareda, this measurement method shows promise as a relatively quick way to gauge differences in dust levels because drones offer an enhanced ability to measure what's in a dust cloud. EPA-trained specialists sat atop an empty container and overlooked the orchard before them to conduct the EPA Method 9 Visual Emissions Evolution, otherwise known as the "eyeball test," as part of Capareda's research trial. "We want to harvest nuts, not dust." – Jesse Roseman Continued from page 2