Odors are often associated with nuisance and health risks. In this study, the atmospheric levels of H₂S and NH₃ were determined in 5 sites near polluted urban rivers during rainy and dry periods in the city of Salvador, Brazil, as well as the relationships between these odorous compounds and meteorological and water quality parameters applying multivariate analysis, and the non-carcinogenic risks (as hazard quotient—HQ). The compounds H₂S and NH₃ were passively sampled and determined by molecular spectrophotometry. Average concentrations were lower in the rainy period (6.56 ± 0.83 μg m⁻³ for H₂S; 8.67 ± 2.50 μg m⁻³ for NH₃) than in the dry period (8.05 ± 1.44 μg m⁻³ for H₂S; 10.62 ± 4.39 μg m⁻³ for NH₃), probably due to lower water and air temperatures, which contribute to lower water–air transfer rates and higher precipitation and relative humidity values, thus favoring the removal of these compounds from the atmosphere. The PCA and HCA results confirmed these relationships, as well as showing strong positive correlations between NH₃, N-NH₄⁺, TN, T_water, BOD, and EC, and strong negative correlations between H₂S, pH, and DO, indicating that these water quality parameters also influence the levels of H₂S and NH₃ in air, thereby confirming a common source for the gas emissions as being mainly from polluted rivers. The maximum H₂S concentrations were above the odor threshold value established by the WHO in both periods. According to deterministic health risk assessment, the HQ values for NH₃ were below the acceptable limit set by USEPA (HQ = 1). However, all HQ values found for H₂S (4.28, 2.80, 1.46 at 95th percentile) for the 3 groups of the exposed population in the dry period using probabilistic risk assessment with Monte Carlo simulation were above this limit, therefore indicating human health risks.

气味通常与滋扰和健康风险有关。在这项研究中，在巴西萨尔瓦多市雨季和旱季期间，在受污染的城市河流附近的 5 个地点测定了大气中 H ₂ S 和 NH ₃的含量，以及这些异味化合物与气象和水质之间的关系应用多元分析的参数，以及非致癌风险（作为危害商数——HQ）。被动取样并通过分子分光光度法测定化合物H ₂ S 和NH ₃。雨季的平均浓度较低（H ₂ S为6.56 ± 0.83 μg m ^-3；NH ₃为8.67 ± 2.50 μg m ^-3) 比干燥期（H ₂ S为8.05 ± 1.44 µg m ^-3；NH ₃为10.62 ± 4.39 µg m ^-3），可能是由于较低的水温和空气温度，这有助于降低水-空气转移率和较高的降水和相对湿度值，从而有利于从大气中去除这些化合物。PCA 和 HCA 结果证实了这些关系，并且显示出 NH ₃、N-NH ₄ ⁺、TN、T_水、BOD 和 EC 之间的强正相关，以及 H ₂ S、pH 和 DO之间的强负相关，表明这些水质参数也会影响 H ₂的水平空气中的S 和 NH ₃，从而确认气体排放的共同来源主要来自受污染的河流。两个时期的最大 H ₂ S 浓度均高于 WHO 确定的气味阈值。根据确定性健康风险评估，NH ₃的 HQ 值低于 USEPA 设定的可接受限值（HQ = 1）。然而，使用蒙特卡罗模拟的概率风险评估为干燥期的 3 组暴露人群发现的 H ₂ S 的所有 HQ 值（4.28、2.80、1.46 在第 95 个百分位数）均高于此限值，因此表明存在人类健康风险.