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To date, only a few studies focused on the carbon monoxide (CO) production during waste composting; all targeted on CO inside piles. Here, the CO net emissions from compost piles and the assessment of worker’s occupational risk of exposure to CO at large-scale composting plants are shown for the first time. CO net emissions were measured at two plants processing green waste, sewage sludge, or undersize fraction of municipal solid waste. Effects of the location of piles (hermetised hall vs. open yard) and turning (before vs. after) were studied. Higher CO net emission rates were observed from piles located in a closed hall. The average CO flux before turning was 23.25 and 0.60 mg‧m-2‧h-1 for hermetised and open piles, respectively, while after– 69.38 and 5.11 mg‧m-2‧h-1. The maximum CO net emissions occurred after the compost was turned (1.7x to 13.7x higher than before turning). The top sections of hermetised piles had greater CO emissions compared to sides. Additionally, 5% of measurement points of hermetised piles switched to ‘CO sinks’. The 1-h concentration in hermetised composting hall can reach max. ~50 mg CO∙m-3 before turning, and >115 mg CO∙m-3 after, exceeding the WHO thresholds for a 1-h and 15-min exposures, respectively.

迄今为止，仅有少数研究聚焦于垃圾堆肥过程中的一氧化碳（carbon monoxide, CO）生成，且现有研究均仅关注堆体内部的一氧化碳浓度。本研究首次披露了堆肥堆体的一氧化碳净排放量，并首次对大型堆肥厂作业人员的一氧化碳职业暴露风险进行了评估。研究在两座分别处理绿化垃圾、污泥以及市政生活垃圾筛下物的堆肥厂开展了一氧化碳净排放量的测定，同时探究了堆体布设位置（密闭车间 vs 露天堆场）与翻堆作业（翻堆前 vs 翻堆后）对排放的影响。结果显示，布设于密闭车间内的堆体具有更高的一氧化碳净排放速率：密闭堆体与露天堆体在翻堆前的平均一氧化碳通量分别为23.25与0.60毫克·米⁻²·小时⁻¹，翻堆后则分别升至69.38与5.11毫克·米⁻²·小时⁻¹。一氧化碳净排放量峰值均出现在堆肥翻堆后，较翻堆前提升1.7至13.7倍。相较于堆体侧壁，密闭堆体的顶部区域具有更高的一氧化碳排放量。此外，有5%的密闭堆体监测点位转变为‘一氧化碳汇’。密闭堆肥车间内的1小时平均一氧化碳浓度在翻堆前最高可达约50毫克·米⁻³，翻堆后则超过115毫克·米⁻³，分别超出世界卫生组织（World Health Organization, WHO）规定的1小时暴露与15分钟暴露阈值。