'Time will tell' whether Walleys Quarry gas emissions will stay low following the closure of the site, councillors have been told.

The Environment Agency served a closure notice on the Silverdale landfill in November, banning the importation of waste and requiring the capping of the site and the installation of gas infrastructure.

Last month saw a marked reduction in hydrogen sulphide levels in the area around Walleys Quarry, following a spike in emissions in January.

But scrutiny committee members at Newcastle Borough Council were told that it is too early to know whether this will be a permanent improvement.

The meeting of the health, wellbeing and environment scrutiny committee came just days after landfill operator Walleys Quarry Ltd entered liquidation, leaving a huge question mark over the future of the site.

Nesta Barker, director of regulatory services at the borough council, said she expected further updates around the liquidation.

She said: "As members can appreciate, liquidation of the company does ultimately remove Walleys Quarry Ltd from the operation of the landfill site. This is a fast-paced and evolving situation.

"The EA will update their engagement website when they have further news to share with the community.

"We will offer the EA and the liquidator any support we can within our powers to keep this landfill under control, as it is currently.

"The work on capping and gas infrastructure required by the EA through the first stages of the closure notice has largely been carried out, and we will continue to monitor the data in relation to the landfill, and we will continue to undertake odour monitoring and assessments in the community."

Hydrogen sulphide levels hit record levels in thee week ending January 12, breaching the 'annoyance' threshold between 37.6 and 56.4 per cent of the time at the three monitoring stations around Walleys Quarry. That week also saw more than 3,800 odour complaints to the EA.

But in the week ending February 16, all three monitoring sites recorded zero breaches of the annoyance threshold, for the first time since last August.

Cllr Paul Northcott suggested that the drop in gas emissions could be related to milder weather conditions, which have resulted in improvements in the past.

He said: "Would it be fair to assume that thee downturn in figures in February were due to the milder conditions? January had mean temperatures that were far lower for far longer, that affected the flow of air.

"So it seems reasonable to suggest that February was more to with the milder conditions rather than any vast improvements."

Ms Barker said the long-term impact of the capping and gas infrastructure would become clearer over time.

She said: "It's very hard to make a direct correlation, and that's why I say time will tell.

"Throughout this whole incident we do know there's a correlation between certain weather conditions and the incidents of the community being affected by the gases."

While the initial works required by the closure notice have now been mostly carried out, further measures relating to the site's restoration and aftercare still need to be done. Walleys Quarry Ltd had been in the process of appealing against the closure notice, but its legal bid to temporarily reopen the site was rejected.

The EA has said that the liquidators will still have to comply with the site's environmental permit and the closure notice.