Politicians, scientists and environmentalists have turned up the heat on ministers and officials planning to merge the British Antarctic Survey with an oceanography centre, before a meeting to decide its fate on Thursday.

Opponents of the plan, which is intended to save money, say the merger would irreparably damage the institution which discovered the ozone hole and is considered a world leader in polar research. The plan attracted further controversy when the Guardian revealed the merger would require BAS to use its skills to help "de-risk" investment for UK oil companies exploring the polar regions.

"Only a few years ago Prime Minister David Cameron was photographed hugging huskies in the Arctic in an effort to stress his green credentials; I hope he can now reassure us that his government would not be so cynical as to refocus the UK's Arctic research on opening up the region to greater resource extraction," said Joan Walley, the Labour MP who chairs the environmental audit select committee. The proposed merger should be abandoned, Walley wrote on Wednesday in a letter to a parliamentary inquiry into the issue.

Amidst growing concerns with the health effects of airborne particles, Air Monitors, a specialist instrumentation company, is launching a new portable air sampler which significantly enhances the ability to measure and control biological contamination.
 
The ‘Coriolis µ’ has a new wet-walled cyclone technology that improves bioaerosol sampling for bacteria, pollen, endotoxins, viruses and fungal spores. Traditional techniques rely on the impact of biological particles on a solid growth medium, but the Coriolis µ collects the particles in a liquid at a high flow rate (300 l/m) with validated efficiency. The liquid containing the particles is compatible with a number of the latest rapid microbiological analysis methods.

Amid warnings that land deals are undermining food security, the head of the UN's Food and Agriculture Organisation (FAO) has compared "land grabs" in Africa to the "wild west", saying a "sheriff" is needed to restore the rule of law.

José Graziano da Silva, the FAO's director general, conceded it was not possible to stop large investors buying land, but said deals in poor countries needed to be brought under control.

"I don't see that it's possible to stop it. They are private investors," said Graziano da Silva in a telephone interview. "We do not have the tools and instruments to stop big companies buying land. Land acquisitions are a reality. We can't wish them away, but we have to find a proper way of limiting them. It appears to be like the wild west and we need a sheriff and law in place."

Imports of Ash from Europe will be banned on Monday in an attempt stop a deadly disease wiping out most of the species' 80m trees in the UK, despite the fungus behind ash dieback first being discovered in the country eight months ago.

Chalara fraxinea has already killed 90% of Denmark's ash, and on Wednesday it was confirmed the disease had spread beyond plantations and nurseries into trees in the wild in Norfolk and Suffolk. The find has raised fears of a repeat of the epidemic of Dutch elm disease in the 1970s, which wiped out virtually the entire mature population of elm trees – 25m – by the 1990s.