AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Space and Seasonal Evaluation of Hydrogen Sulfide Levels in Surrounding Cerro Prieto Geothermal Plant at Mexicali, B.C., Mexico
LIZETH AGUILAR, Guillermo Rodríguez-Ventura, Penelope Quintana, Miguel Zavala, Luisa Molina, Universidad Autónoma de Baja California
Abstract Number: 556 Working Group: Aerosol Exposure
Abstract Geothermal plants can be an important source of alternative energy. However, one concern is the potential for toxic emissions. Cerro Prieto Geothermal Plant (CPGP) is located on the US-Mexican border at Mexicali, Baja Calfornia and is reported to release 4.9 tons per hour of hydrogen sulfide (H2S), which could affect the health of people that live in surrounding towns. H2S is an important pollutant gas in the low atmosphere, which is oxidized by photochemical species and produces sulfur dioxide and eventually sulfates. Measurements of hydrogen sulfide levels in 2010 showed an average daily concentration of 41 µg/m3 inside the plant and a range of 1-45 µg/m3 at surrounding towns. This new study characterized H2S levels around CPGP to investigate the factors affecting the spatial distribution of H2S and to provide information needed for mapping air quality levels for nearby towns. H2S measurements (n = 177) were carried out from November 2013 to June 2014 at three towns: SS-1 (Delta), SS-2 (Chimi) and SS-3 (Nuevo Leon). H2S sampling was carried out using Radiello passive absortion cartridges (Sigma Aldrich) impregnated with zinc acetate which formed zinc sulfide, extracted by deionized water and analyzed visible spectrophotometry by the methylene blue method. Average H2S concentrations from autumn-winter 2013 were 90.9,61.9 and 20.1 µg/m3 for SS-1,SS-2 and SS-3 respectively, and during spring-summer 2014 were 46.9, 62.5 and 23.1 µg/m3 respectively. H2S peak concentrations were 172.6 and 257.2 µg/m3 for SS-1 during autumn-winter 2013 and 192.3 µg/m3 for SS-2 during spring-summer 2014, which are higher than the standard established by WHO (150 µg/m3). Higher wind speeds were associated with elevated concentrations. These results indicate that nearby towns could potentially experience adverse levels of H2S due to the emissions from of the geothermal plant.