BACKGROUND Cigarette butts are some of the most common form of litter in the World, causing severe environmental damage. Analysing spatial distribution of cigarette butts in the urban environment may lead to useful insights for further interventions to reduce this form of litter. In this study, we present a GIS-based methodology to estimate the density of cigarette butts across a large urban area. METHODS We collected information about discarded cigarette butts in outdoor public spaces by systematic social observation in a diverse sample of areas in Madrid, Spain. We used these data to estimate the density of cigarette butts in public spaces around the entire city by performing GIS analyses based on Kernel Density Estimations. Last, we validated these measures using on-field observations in a set of locations across the city. RESULTS Hospitality venues and public transportation stops were the places with the highest concentrations of cigarette butts, followed by the entrances to educational venues and playgrounds. Central districts showed the highest amount of cigarette butts in contrast to peripheral ones. We found that our measure had good validity, with a correlation coefficient of 0.784. DISCUSSION This is the first study estimating and mapping cigarette butt litter in a large urban area. We identified a set of outdoor public places with high concentrations of cigarette butts and found geographical unevenness in the distribution of this pervasive form of litter across the study area. Our findings demonstrate the ubiquitous nature of cigarette butts in the urban environment and the need for interventions to reduce its impact on both people's health and the environment.

中文翻译：

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估计和绘制城市环境中乱扔烟头的情况：GIS 方法。

背景技术烟头是世界上最常见的垃圾形式之一，造成严重的环境破坏。分析城市环境中烟头的空间分布可能会为进一步采取干预措施减少这种形式的垃圾提供有用的见解。在这项研究中，我们提出了一种基于 GIS 的方法来估计大型城市地区的烟头密度。方法 我们通过对西班牙马德里不同地区样本的系统社会观察，收集了有关室外公共场所丢弃烟头的信息。我们使用这些数据通过基于核密度估计进行 GIS 分析来估计整个城市公共场所的烟头密度。最后，我们通过在全市多个地点的现场观察来验证这些措施。结果接待场所和公共交通站点是烟头最集中的地方，其次是教育场所和游乐场的入口。与周边地区相比，中心地区的烟头数量最多。我们发现我们的测量具有良好的有效性，相关系数为 0.784。讨论 这是第一项对大城市地区的烟蒂垃圾进行估计和绘制的研究。我们确定了一组烟头高度集中的户外公共场所，并发现这种普遍存在的垃圾在整个研究区域的分布存在地理不均匀性。我们的研究结果表明，烟头在城市环境中无处不在，并且需要采取干预措施来减少其对人们健康和环境的影响。