Seasonal variations of PM10 — Trace elements, PAHs and Levoglucosan: Rural sugarcane growing area versus coastal urban area in Southeastern Florida, USA. Part II: Elemental concentrations--颗粒学报PARTICUOLOGY

Sevimoğlu, O., & Rogge, W. F. (2019). Seasonal variations of PM10 — Trace elements, PAHs and Levoglucosan: Rural sugarcane growing area versus coastal urban area in Southeastern Florida, USA. Part II: Elemental concentrations. Particuology, 46, 99-108. https://doi.org/10.1016/j.partic.2019.05.001

Seasonal variations of PM₁₀ — Trace elements, PAHs and Levoglucosan: Rural sugarcane growing area versus coastal urban area in Southeastern Florida, USA. Part II: Elemental concentrations

Orhan Sevimoğlu ^a *, Wolfgang F. Rogge ^b

a Department of Environmental Engineering, Gebze Technical University, Gebze, Kocaeli, 41400, Turkey
b School of Engineering and Sierra Nevada Research Institute, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA

10.1016/j.partic.2019.05.001

Volume 46, October 2019, Pages 99-108

Received 18 February 2017, Revised 27 April 2019, Accepted 10 May 2019, Available online 29 June 2019, Version of Record 8 August 2019.

E-mail: sevimoglu@gtu.edu.tr

Highlights

• Dynamic evolution of complex ambient aerosol due to urban sources and sugarcane foliage burning.

• Ambient levels of K, PAHs and levoglucosan in PM₁₀ during sugarcane burning vs growing season.

• Using K and levoglucosan as markers, rural PAH levels results from sugarcane harvest burning and related activities.

• Sea-salt aerosols are a major contributor to the PM₁₀. Dichlorination results in release of gaseous HCl.

Abstract

The largest sugarcane-growing area in the United States is in South Florida. An estimated 7 million tons of dry sugarcane leafy biomass is removed from the fields before harvest by burning the leaves off the sugarcane stalks. Preharvest sugarcane leaf foliage burning is a major source of airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), biogenic trace elements such as K, volatile hydrocarbons and other pollutants. In one harvesting period, approximately 22 million tons of CO₂, a greenhouse gas, is released, 7 million tons from leaf foliage preharvest burning alone and 15 million tons from burning sugarcane bagasse in the sugar mills for power generation. In this study, PM₁₀ was collected from Belle Glade, close to the sugarcane-growing area, and from Delray Beach, an urbanized area along the East Coast of Florida. The PM samples were analyzed for trace elements and close to organic compounds. To elucidate the importance of preharvest sugarcane biomass smoke emissions on air quality, 39 trace elements, 18 PAHs, and levoglucosan were selected to apportion ambient PM constituents. Al, Ca and to a great extend also Mg are the major soil-related trace elements and key markers for fugitive soil dust emissions. Similarly, sea salt aerosol blown from the Atlantic Ocean into Florida added appreciably to PM₁₀ trace elements concentration, especially Na and Cl. Approximately half of the sea salt aerosol (PM₁₀ -portion) by mass is removed from the atmosphere during the transport of ocean air from Delray Beach to Belle Glade. Ambient acid displacement reactions caused a substantial portion of the Cl (˜30%) to be liberated from the sea salt aerosol to the atmosphere during transport as gaseous HCl. The PAH concentrations at Belle Glade were high when the biomass combustion markers levoglucosan and K also showed the highest concentrations. This indicates that during the sugarcane harvest season, when leaf foliage is burned off just before harvest, most of the ambient PAHs associated with PM₁₀ are indeed related to preharvest burning, harvesting machinery emissions, bagasse burning in sugarcane mills, and other related activities that consume biomass and/or fossil fuels for sugarcane harvesting and processing.

Graphical abstract

Keywords

Urban versus rural; Trace elements; Sugarcane burning; Rare earth elements; Sea salt aerosol; Potassium; Levoglucosan; PAHs

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