Open burning of plastic waste may pose a significant threat to global health by degrading air quality, but quantitative research on this problem -- crucial for policy making -- has been stunted by lack of data. Many low- and middle-income countries, where open burning is most concerning, have little to no air quality monitoring. Here, we leverage remotely sensed data products combined with spatiotemporal causal analytic techniques to evaluate the impact of large-scale plastic waste policies on air quality. Throughout, we study Indonesia before and after 2018, when China halted its import of plastic waste, resulting in diversion of this massive waste stream to other countries. We tailor cutting-edge statistical methods to this setting, estimating effects of increased plastic waste imports on fine particulate matter (PM$_{2.5}$) near waste dump sites in Indonesia as a function of proximity to ports, an induced continuous exposure. We observe strong evidence that monthly PM$_{2.5}$increased after China's ban (2018-2019) relative to expected business-as-usual (2012-2017), with increases up to 1.68 $μ$g/m$^3$ (95% CI = [0.72, 2.48]) when exposed to medium-high port proximity. Effects were more modest for very high port proximity exposure, possibly reflecting smaller increases in dumping/burning where government oversight is greater.

翻译：塑料废物的露天焚烧可能通过降低空气质量对全球健康构成重大威胁，但这一对政策制定至关重要的问题因缺乏数据而长期缺乏定量研究。在许多露天焚烧问题最为严峻的低收入和中等收入国家，空气质量监测几乎缺失。本文利用遥感数据产品结合时空因果分析技术，评估大规模塑料废物政策对空气质量的影响。我们以2018年中国停止进口塑料废物前后（导致该巨量废物流向转向其他国家）的印度尼西亚为研究对象，针对这一情境定制了前沿统计方法，通过连续暴露暴露变量（即与港口的距离）来估计塑料废物进口增加对印度尼西亚废物倾倒点附近细颗粒物（PM$_{2.5}$）的影响。我们观察到强有力的证据表明：在中等偏高港口邻近度暴露条件下，中国禁令实施后（2018-2019年）的月均PM$_{2.5}$相对于预期基线情景（2012-2017年）有所上升，最大增幅达1.68 $μ$g/m$^3$（95%置信区间=[0.72, 2.48]）。在极高港口邻近度暴露条件下，效应较为温和，可能反映了政府监管较强的区域废物倾倒/焚烧量的增幅较小。