Under-researched and under-reported new findings in microplastic field

After over 20 years of research on microplastic (MP) pollution, there are important areas of study which are still at the inception. In particular, between 2020 and 2023 new findings on MP have emerged, which open new sub-categories of MP research. These research areas include sea surface MP ejection, direct and indirect MP influence on climate and hydrological cycle, small and nano-sized MP analysis and the relationship between MP size and abundance. Not reported or barely mentioned in previous reviews, these globally-relevant findings are here highlighted and discussed with aim to promote their further research that will potentially result in new evidence of detrimental effects of MP pollution on the biosphere.