Ammonia emissions from livestock facilities around an international airport, Tehran, Iran: An experimental and mathematical study

Abstract

Ammonia emissions from livestock farms are a major problem for staff and residents near these centers. Anaerobic decomposition of livestock waste and the collection and stacking of waste are the main sources of ammonia gas on livestock farms. This article examined ammonia emissions from livestock facilities near Tehran Imam Khomeini International Airport. First, field measurements were made in the summer (30°C), and collected samples were examined using the indophenol technique. AERMOD, based on Gaussian fluctuating plume theory, was constructed to model ammonia emissions. According to AERMOD, the maximum periodic‐seasonal 2‐hourly and 8‐hourly ammonia concentrations were 15.9, 229, and 63.7 OU (odor unit per unit volume)/m3, respectively. The hourly ammonia emission rate from livestock sources is also 0.0168 gm−2 h−1. AERMOD results mathematical model indicated reasonable agreement with the field measurement, which the coefficient of determination (R2), index of agreement (d), and efficiency coefficient (E) were 0.95, 0.97, and 0.91, respectively. Moreover, Statistical indices, including geometric mean bias (MG), geometric variance (VG), fraction of predictions within a factor of two of observations (FAC2), and normalized mean square error (NMSE), the root mean square error (RMSE) and mean absolute error (MAE) are also indicated by 1.36 and 0.67, respectively, were used to assess the reliability of the model results showed that AERMOD had a good agreement with the field measurement.