Whatever one's view of Frieze Art Fair – which lowers its copious behind onto the green grass of Regent's Park come October – there's no question that for that one week at least, London is the centre of the contemporary art market. During Frieze Week London is flooded with gallerists, critics, curators and art-buying oligarchs from across the world, and the impact on the capital's art scene is immeasurable. All across town, the commercial galleries strive to put on their very best shows, artist-run spaces clamour for attention, and many of the big public institutions choose Frieze week during which to open their major exhibitions.

In addition, of course, are all the other art fairs. And this year there seem to be more than ever. As well as established fixtures like Affordable Art Fair, Multiplied, 20/21, Art London, London Art Fair etc, 2011 also sees the return of both Moniker and SUNDAY Art Fair for their second years. Several new fairs are launching too: Moving Image London, with a focus on video art; Sluice Art Fair, emphasising not-for-profit artist-run spaces; and then later in the year, Affordable Art Fair are opening a second London fair, in Hampstead, and The Other Art Fair is allowing artists to bypass the gallery system and sell straight to the public.

This explosion of new fairs suggests some structural shifts in the way art is bought and sold, as the fair and the auction now seem to dominate market news. In addition each new fair contributes something new to the art fair experience. Just as Moving Image stemmed out of the need to supplement existing art fairs (“In New York,” organiser Ed Winkleman explains, “about 1/3 of the galleries showing a video at Moving Image were also participating in one of the other larger fairs”), so too did SUNDAY. Rebecca May Marston, one of the organisers of SUNDAY, explains how the fair grew out of something lacking from Frieze: “We realised Frieze Frame was a project-selected section rather than gallery-selected section, and so when many of us didn't get in second time round in 2010 we decided we needed to do something else, which also coincided with Zoo ending.”

With the demise of the much-loved Zoo Art Fair after 2009, as well as the cancellation of SELECT Art Fair due to “challenging market conditions” you'd think this would be a difficult time to launch a new art fair. But Marston, who is also Director of Hoxton-based contemporary art gallery Limoncello, suspects that the end of Zoo actually paved the way for this proliferation of new fairs: “Zoo was so strong that when it departed it left a gap open for more,” she opines. On the other hand, Winkleman suggests that it's a global phenomenon: “It's not just London. There are more fairs nearly everywhere right now, because the place collectors buy art has shifted from the gallery to the fairs. There are more fairs because more galleries have recognised this shift.”