Global-scale detection of plastic from space with the EMIT imaging spectrometer

The increase in international production of plastics since the 1950s and waste mismangement have contributed to the proliferation of microplastics. Understanding plastic presence on land is crucial, as most pollution originates from land-based sources. From its vantage point on the International Space Station, NASA’s EMIT imaging spectrometer collects high signal-to-noise surface reflectance spectra (380–2500 nm). These spectra are obtained for every point within the imaged area, with 60-meter spatial sampling. We present a study using this instrument to detect distinctive absorption features of High-density polyethylene (HDPE) and poly(vinyl chloride) (PVC) plastics in the shortwave infrared. By applying a column-wise adaptive matched filter and using an open-access spectral library, we successfully inferred signatures of these two types of plastics across multiple continents between latitudes bounds of +/- 52 degrees, primarily related to agricultural practices. Our study underscores the importance of monitoring land-based sources of plastic pollution to guide future mitigation strategies.