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]) at dump sites with medium-high port proximity. Effects were more modest at sites with very high port proximity, 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恶化空气质量对全球健康构成重大威胁，但针对这一问题的定量研究——对政策制定至关重要——因数据缺乏而受阻。在露天焚烧问题最为突出的许多中低收入国家，空气质量监测几乎为零或极为有限。本研究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。我们以印度尼西亚为研究对象，聚焦2018年前后时期——当时中国停止进口塑料废物，导致这一庞大的废物流转向其他国家。我们为此场景定制前沿统计方法，通过将港口邻近度作为诱导的连续暴露变量，估计塑料废物进口量增加对印度尼西亚垃圾堆放场附近细颗粒物（PM$_{2.5}$）浓度的影响。我们观察到有力证据表明，相对于预期的常规情景（2012-2017年），中国禁令实施后（2018-2019年）的月均PM$_{2.5}$浓度有所上升，在港口邻近度中高的堆放场，浓度增幅最高达1.68 $μ$g/m$^3$（95\% CI = [0.72, 2.48]）。在港口邻近度极高的场地，效应较为有限，这可能反映了在政府监管较强的区域，倾倒/焚烧活动的增量较小。