The size of the patch is indefinite, as is the precise distribution of debris because large items are uncommon. Most debris consists of small plastic particles suspended at or just below the surface, evading detection by aircraft or satellite. Instead, the size of the patch is determined by sampling. The estimated size of the garbage patch is (about twice the size of Texas or three times the size of France). Such estimates, however, are conjectural given the complexities of sampling and the need to assess findings against other areas. Further, although the size of the patch is determined by a higher-than-normal degree of concentration of pelagic debris, there is no standard for determining the boundary between "normal" and "elevated" levels of pollutants to provide a firm estimate of the affected area. In August 2009, the
Scripps Institution of Oceanography/
Project Kaisei SEAPLEX survey mission of the Gyre found that plastic debris was present in 100 consecutive samples taken at varying depths and net sizes along a path of through the patch. The survey found that, although the patch contains large pieces, it is on the whole made up of smaller items that increase in concentration toward the gyre's centre, and these '
confetti-like' pieces that are visible just beneath the surface suggests the affected area may be much smaller. Data collected in 2009 from Pacific
albatross populations suggest the presence of two distinct debris zones. In March 2018,
the Ocean Cleanup published a paper summarizing their findings from the Mega- (2015) and Aerial Expedition (2016). In 2015, the organization crossed the Great Pacific garbage patch with 30 vessels, to make observations and take samples with 652 survey nets. They collected a total of 1.2 million pieces, which they counted and categorized into their respective size classes. In order to also account for the larger, but more rare debris, they also overflew the patch in 2016 with a
C-130 Hercules aircraft, equipped with
LiDAR sensors. The findings from the two expeditions, found that the patch covers with a concentration of . They estimate an in the patch, with 1.8 trillion plastic pieces, out of which 92% of the mass is to be found in objects larger than . NOAA stated: Further contrary to popular belief, the Great Pacific Garbage Patch cannot be seen from space. In a 2001 study, researchers found concentrations of plastic particles at with a mean mass of , in the neuston. The overall concentration of plastics was seven times greater than the concentration of
zooplankton in many of the sampled areas. Samples collected deeper in the water column found much lower concentrations of plastic particles (primarily
monofilament fishing line pieces). In 2012, researchers Goldstein, Rosenberg and Cheng found that microplastic concentrations in the gyre had increased by two
orders of magnitude in the prior four decades. On 11 April 2013, artist
Maria Cristina Finucci founded
The Garbage Patch State at
UNESCO – Paris in front of Director General
Irina Bokova. In March 2018,
New Scientist published the prediction that the size was approximately 1.6 million square kilometers. == Environmental effects ==