The environmental sources of microbial aerosols and processes by which they are emitted into the atmosphere are not well characterized. In this study we analyzed microbial cells and biological ice nucleating particles (INPs) in smoke emitted from eight prescribed wildland fires in North Florida. When compared to air sampled prior to ignition, samples of the air–smoke mixtures contained fivefold higher concentrations of microbial cells (6.7 ± 1.3 × 10⁴ cells m⁻³) and biological INPs (2.4 ± 0.91 × 10³ INPs m⁻³ active at temperatures ≥ −15 °C), and these data significantly positively correlated with PM₁₀. Various bacteria could be cultured from the smoke samples, and the nearest neighbors of many of the isolates are plant epi- and endophytes, suggesting vegetation was a source. Controlled laboratory combustion experiments indicated that smoke emitted from dead vegetation contained significantly higher numbers of cells, INPs, and culturable bacteria relative to the green shrubs tested. Microbial viability of smoke aerosols based on formazan production and epifluorescent microscopy revealed no significant difference in the viable fraction (~80%) when compared to samples of ambient air. From these data, we estimate each fire aerosolized an average of 7 ± 4 × 10⁹ cells and 2 ± 1 × 10⁸ biological INPs per m² burned and conclude that emissions from wildland fire are sources of viable microbial aerosols to the atmosphere.

微生物气溶胶的环境来源及其排放到大气中的过程尚未得到很好的表征。在这项研究中，我们分析了北佛罗里达州八场规定的野火排放的烟雾中的微生物细胞和生物冰核颗粒 (INP)。与点火前采样的空气相比，空气-烟雾混合物的样品中微生物细胞（6.7 ± 1.3 × 10 ^{4 个} 细胞 m ^-3）和生物 INPs（2.4 ± 0.91 × 10 ^{3 个} INPs m ^-3活性）浓度高出五倍在 ≥ -15 °C 的温度下），这些数据与 PM _{10显着正相关}. 可以从烟雾样本中培养出各种细菌，许多分离物的最近邻居是植物表生菌和内生菌，这表明植物是一个来源。受控的实验室燃烧实验表明，与测试的绿色灌木相比，死亡植被散发的烟雾中含有显着更多数量的细胞、INP 和可培养细菌。与环境空气样本相比，基于甲臜产生和落射荧光显微镜的烟雾气溶胶的微生物生存能力显示，活分数（~80%）没有显着差异。根据这些数据，我们估计每场火灾平均每 m ^{2雾化 7 ± 4 × 10 9 个}细胞和 2 ± 1 × 10 ⁸个生物 INP燃烧并得出结论，野火的排放物是大气中可行的微生物气溶胶的来源。