|Parnell Jr, C|
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2009
Publication Date: 4/5/2009
Citation: Wanjura, J.D., Faulkner, W.B., Parnell Jr, C.B., Shaw, B.W., Capareda, S.C., Lacey, R.E. 2009. Source sampling of particulate matter emissions from cotton harvesting: System field testing and emission factor development. Transactions of the ASABE. 52(2):591-597. Interpretive Summary: Cotton harvesting in California and Arizona has been identified as a significant source of particulate matter (PM) pollution based on calculated annual emissions. The PM emission factors used by regulators in California and Arizona to calculate annual emission inventories were developed with instruments and methods that have since been shown to contain substantial levels of uncertainty leading to the overestimation of PM emissions. The purpose of this work is to document the testing protocol and PM emission factors for cotton harvesting developed using a novel source testing system. The testing system was developed to measure PM emissions onboard a six row cotton picker as the machine harvested cotton in the field. The resulting emission factors contain low levels of uncertainty due to the design and precise control of the sampling system. PM emission factors were developed for three particle size indicators, total suspended particulate (TSP), PM10 (particle diameters less than or equal to 10 micrometers), and PM2.5 (particle diameters less than or equal to 2.5 micrometers) using the results of particle size distribution analyses. The area based TSP, PM10, and PM2.5 emission factors developed in this work are 1.64, 0.55, and 1.58E-03 kg ha-1, respectively (1.46, 0.49, and 1.41E-03 lb ac-1, respectively). In terms of PM emitted per harvested cotton mass, the TSP, PM10, and PM2.5 emission factors are 0.22, 0.07, and 2.15E-4 kg bale-1, respectively (0.48, 0.15, and 4.74E-4 lb bale-1, respectively). The PM10 emission factor developed in this work is approximately 3.5 times lower than the PM10 emission factor currently used to regulate cotton harvesting in CA. The use of accurate emission factors will help producers and regulators focus their PM emission reduction efforts on the processes and operations that contribute most to regional PM pollution levels.
Technical Abstract: Emission factors are used in the air pollution regulatory process to quantify the mass of pollutants emitted from a source. Accurate emission factors must be used in the air pollution regulatory process to ensure fair and appropriate regulation for all sources. Agricultural sources, including cotton production operations, are not exempt from air quality regulation. Particulate matter (PM) emissions from agricultural operations are complex to quantify due to the physical characteristics of emission source, particle size distribution of the PM emitted, and natural dispersion of emissions into the environment. These factors have introduced substantial amounts of uncertainty into previous emission factor estimates from cotton harvesting operations. This article documents a new protocol for measuring PM emissions onboard a cotton harvester using a novel source sampling system and reports TSP, PM10, and PM2.5 emission factors developed using the new protocol. The average systematic uncertainty of the measured emission rates is 2.78%. Significant correlations were observed between test plot yield and TSP, PM10, and PM2.5 emission rates indicating that it is appropriate to report emission factors on a mass of PM emitted per mass of cotton harvested basis. The area based TSP, PM10, and PM2.5 emission factors developed in this work are 1.64, 0.55, and 1.58E-03 kg ha-1, respectively (1.46, 0.49, and 1.41E-03 lb ac-1, respectively). In terms of PM emitted per harvested cotton mass, the TSP, PM10, and PM2.5 emission factors are 0.22, 0.07, and 2.15E-4 kg bale-1, respectively (0.48, 0.15, and 4.74E-4 lb bale-1, respectively).