Plastic doesn't biodegrade because no organisms can digest it. Instead, sunlight, wind, waves, and abrasion break it down into increasingly smaller fragments known as microplastics—pieces under 5 millimetres in size. These microplastics disperse throughout the environment, infiltrating ecosystems and food chains. Once consumed, they can accumulate in human tissues. Recent research has uncovered microplastics within cloud vapour, where they may influence climate and precipitation. Clouds form when water vapour condenses onto airborne particles, known as condensation nuclei, which include substances such as mineral dust, pollen, and bacteria. Sea salt lifted by ocean breezes can also serve as condensation nuclei. Similarly, microplastics suspended in the air due to their light weight can facilitate the formation of water droplets or ice crystals, potentially triggering rain, snow, or hail. Since clouds regulate Earth’s energy balance by reflecting sunlight and absorbing heat, microplastic-driven cloud formation could have far-reaching climatic effects. The study identified four common types of atmospheric plastic: low-density polyethylene, polypropylene, polyvinyl chloride, and polyethylene terephthalate—materials widely used in everyday items like bottles, packaging, and household goods. To fully understand their impact on clouds and climate, scientists need to measure microplastic concentrations at cloud-forming altitudes and compare them with other condensation nuclei like mineral dust and biological particles. Further research should also assess plastics with additives, such as dyes, and even smaller particles to evaluate their atmospheric effects.
Read more...
