A study published in the Journal of the Royal Statistical Society Series C: Applied Statistics used satellite data and causal inference methods to assess air quality impacts near Indonesian waste disposal sites after China's 2018 plastic waste import ban.
Key Details
- The study focused on 356 waste dump sites in Indonesia, identified via satellite imagery and machine learning (Global Plastic Watch).
- A port-proximity index was developed to estimate exposure to imported plastic waste.
- PM2.5 data were derived from satellite observations, atmospheric models, and ground measurements.
- Fire activity was distinguished using satellite-based fire detections.
Results
After the ban, PM2.5 concentrations at dump sites increased by an average of 0.86 μg/m³ (3.3%) above expected levels.
Sites with moderate-to-high waste import exposure saw increases up to 1.68 μg/m³. Fire activity at dump sites also increased from 2018 to 2019. Notably, pollution effects were not strongest at sites closest to major ports; intermediate exposure sites showed larger increases.
Methodology
- Researchers used a quasi-experimental causal inference framework with historical data, machine learning, and spatial modeling.
- Controls included weather, population density, and regional fire activity.
- Results were validated against independent statistical methods.
Context
China's 2018 ban redirected plastic waste to Southeast Asia, with Indonesia becoming a primary destination.
Open burning of plastic waste releases fine particulate matter. This study provides observational evidence linking waste trade policy changes to local air quality.