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Atmospheric LiDAR coupled with point measurement air quality samplers to measure fineparticulate matter (PM) emissions from agricultural operations. Part 2 of the California 2007 - 2008 Tillage Campaigns: Spring 2008 Data Analysis
Citation:
Williams, D., J. Hatfield, J. Sweet, AND S. Chilingaryan. Atmospheric LiDAR coupled with point measurement air quality samplers to measure fineparticulate matter (PM) emissions from agricultural operations. Part 2 of the California 2007 - 2008 Tillage Campaigns: Spring 2008 Data Analysis. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/191, 2014.
Impact/Purpose:
Airborne particles, especially particulate matter 10 micrometers (μm) or smaller in aerodynamic diameter (PM10) and fine particulate matter 2.5 μm or smaller in aerodynamic diameter (PM2.5), are microscopic solids or liquid droplets in the air that can cause serious health problems (e.g.,coughing, difficulty breathing, decreased lung function, asthma, heart attacks, and premature death), especially in people with heart and lung disease. This study used advanced measurement technologies, which link laser-based Ligh Detection and Ranging (LiDAR) systems with conventional point-measurement air quality samplers, to map PM emissions at high spatial and temporal resolution in order to accurately compare CMPs with conventional tillage systems. The purpose of this field study was to determine if and how much particulate emissions differ between the conventional method of agricultural fall tillage and a conservation tillage CMP. It is a companion study to an earlier study performed in October 2007 near Los Banos, CA investigating the control efficiency of combined operations CMP versus conventional tillage in the fall tillage sequence.
Description:
Concern with health effects resulting from PM10 exposure is drawing increased regulatory scrutiny and research toward local agricultural tillage operations. To investigate the control effectiveness of one of the current Conservation Management Practices (CMPs) written for agricultural land preparation on the generation of particulate matter (PM) levels, the San Joaquin Valleywide Air Pollution Study Agency funded a project to study: 1) The magnitude, flux, and transport of PM emissions produced by agricultural practices for row crops where tillage CMPs are implemented vs. the magnitude, flux, and transport of PM emissions produced by agricultural practices where CMPs are not implemented. 2) The control efficiencies of equipment used to implement the “conservation tillage” CMP. If resources allow assessing additional CMPs, what are the control efficiencies of the “equipment change/technological improvements” CMP? 3) If these CMPs for a specific crop be quantitatively compared, controlling for soil type, soil moisture, and meteorological conditions.Some of the derived PM10 emission rates from this experiment agree with those reported in the literature, as well as the emission factors used by the State of California Air Resources Board (CARB) to calculate area source PM10 contributions from agricultural tilling [14]; others do not agree and are significantly higher, such as the emission rates for the chisel, disc 1, disc 2, and lister passes. Emissions factor values estimated through inverse modeling for these operations are below the 95% level predicted by statistical distributions fitted to published data; emissions estimates from lidar for the same operations are above the 95% level. While values from published studies are generally not in close agreement, they are within the range of the variability expected from measurements made under different meteorological and soil conditions, as demonstrated by the wide range of values in the literature [12][16]. In general, the emission rates calculated from this study are higher than others reported but are within the variability of other reported emission rates.