Researchers from the Leibniz Institute for Tropospheric Research in Germany have made a significant discovery about tiny plastic particles in city air. They measured microplastics and nanoplastics near a busy road and found concentrated levels of plastic in the air. The study found that the pollution was evenly divided between finer and coarser plastic particles, with much of it being made up of tire particles. The researchers suggest that it is important to include tire abrasion in regulating air quality and setting limits for plastic in air to protect human and environmental health. They also called for long-term studies to confirm the toxicity of different plastic types to support regulatory standards.