The invitation came from festival executive director Douglas Gautier, after he saw the quintet at the Fringe Club playing for an RTHK Radio Four function.

'For us, it makes a big difference in visibility,' says Pelletier, who plays trombone and euphonium among other instruments. 'We'd like to be considered among the other chamber music groups that have a high profile in Hong Kong. That's our goal with this concert, and has been our goal all along. We want to be thought of as a viable option - instead of a string quartet.'

One indication of the group's status is that they'll be performing the festival's only musical world premiere: Chinese Angel by local composer Tang Lok-yin. 'That's one of the most exciting pieces on the programme,' says Pelletier. 'Tang Lok-yin has been commissioned to write a piece for us. Her concept is of an angel descending into the busy streets of Hong Kong, and taking it all in. It combines Chinese instruments with western brass instruments.'

The composer will conduct the 10-minute piece, and the quintet will be joined by three musicians from the Hong Kong Chinese Orchestra. 'We have a suona, which is a piercing double-reed instrument that sounds and looks almost like a trumpet,' says Pelletier.

'Then there's the gaohu, which is a small version of the erhu - a very Chinese sound - and we have a battery of Chinese percussion instruments. We're very excited. It's a world premiere and it's the first time, so far as I'm aware, that Chinese instruments have been combined with a brass quintet.'

A founding member, Pelletier says the quintet was formed in 2003 at the suggestion of bass trombonist Paul Pollard. He approached Pelletier and they set about finding like-minded musicians. 'Although a lot of brass players in Hong Kong come from overseas, we wanted the group to reflect the real mix of players here,' he says. 'Three of our members grew up in Hong Kong, went to the Academy for Performing Arts and worked professionally in the Philharmonic or the Sinfonietta and around town.' The trio are trumpeters Joseph Ngan and Kevin Ngai and horn player Homer Lee.

Part of the quintet's agenda is to show that, although brass instruments tend to be associated with volume, they have their softer side, and that the musicians can produce a range of tones and textures by varying the choice of instrument.

'For this concert, each trumpeter will play three to four instruments, including flugelhorns and piccolo trumpets,' says Pelletier. 'Paul Pollard plays bass trombone and tuba. Homer the horn player is the only one who doesn't switch at all. Just playing that one well is enough of a trick.'

The more rounded tones of the euphonium and the flugel horns will be used on four Claudio Monteverdi madrigals. Although written for voices, the pieces work so well in this instrumental rearrangement that some authorities say that the renaissance brass music of Giovanni Gabrieli may have influenced Monteverdi at the time he composed them. 'Monteverdi didn't write this for brass instruments, but he was a contemporary of the Gabrieli family of composers, and must have heard them as they were beginning to write for brass instruments,' says Pelletier. 'He maybe had that at the back of his mind. These are vocal pieces that are transcribed very well for brass.'

Johann Sebastian Bach's Toccata and Fugue in D Minor - one of his most famous works - was composed for the organ and is still strongly associated with that instrument. However, it's been adapted for various combinations of instruments, and Pelletier says Frederick Mills' arrangement for brass quintet is a particularly successful reinterpretation of the piece. 'It was originally written for organ, but it works quite well for brass because to play it, the organist has to pull out all the brass stops. It's almost a brass section. We have to mask ourselves when it gets into the fiddly bits.'

Viktor Ewald's Brass Quintet No 1 in B flat Minor closes the first half of the programme, and its inclusion is intended as a tribute to the Russian composer, who devoted considerable energies to brass quintets and is regarded as one of the greatest composers for such ensembles.

After the intermission, the music will move into the 20th and 21st centuries, with Witold Lutoslawski's Mini Overture - originally composed for the Philip Jones Brass Ensemble of London - which will set the mood for the second half of the concert. 'It's a very difficult, very demanding 20th-century piece, but not in a 'squeaky hinge, frighten the audience away' sort of way,' says Pelletier. 'It's a very exciting piece. You can hear cities coming to life and the hustle and bustle in the music.'

That sets the stage nicely for the premiere, with Tang Lok-yin's angel negotiating the crowds and pollution of Hong Kong. It's an appropriate piece from a group that had the atmosphere of its home town in mind when it chose its name.

'In Hong Kong, I think we all feel that fresh air is something which is needed,' Pelletier says. 'As brass players, we all use air. We have that aspect to our playing, and we're all concerned about air pollution. The idea was also that the music should be a breath of fresh air.'

Gershwin and Heyward's Porgy and Bess was intended to be a breath of fresh air for opera when it was first performed in 1935, but received a mixed critical reception and was initially a commercial flop - partly because it required an all-black cast in a period when much of the US remained segregated. It's still a controversial work, but nobody questions the quality of Gershwin's music and many of the tunes have become jazz standards.

So, it's perhaps fitting that this concert closes with the Porgy and Bess Suite, arranged by Luther Henderson, which includes the overture and most of the best known tunes, including Summertime, I Loves You Porgy, Bess You is My Woman Now and It Ain't Necessarily So.

'That's the longest piece on the programme,' Pelletier says. 'It would be wrong to call it jazz music, but it certainly isn't classical. There are bits of Dixieland in there, and places where members of the group start clapping and snapping their fingers. It's not really improvised, but there are moments of spontaneity and we're bringing our own perspective to the cadenzas.'

This will, above all, be an evening in which the quintet demonstrates its mastery of dynamics. There'll be loud passages, but also whisper-quiet ones. 'This is a great opportunity for us, and also, I hope, a great opportunity for a Hong Kong audience to experience brass music in a chamber-music setting,' Pelletier says. 'We get that very often.'

Fresh Air Brass Quintet, Feb 22, meet the artists 6.45pm-7.15pm, concert begins 7.45pm, HK City Hall Theatre, $80, $100, $120 Urbtix