Daily briefing: How to clean indoor air of viruses and pollutants

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China’s rover peers under Mars surface

China’s Zhurong rover has peered under the surface of Mars — down to 100 metres — and has found evidence of two huge floods that shaped the landscape. Since May last year, Zhurong has been exploring Utopia Planitia, in Mars’s northern hemisphere. Images from the rover’s ground-penetrating radar found layered patterns under the surface, which the authors suggest are made of sedimentary rocks carried in by two major floods around 3 billion and 1.6 billion years ago. But other scientists say that, although radar is good at detecting layers of subsurface material, it’s less proficient at identifying what layers are made of.

Nature | 5 min read

Brazil election might hinge on COVID

Brazilians preparing for presidential elections in October will consider whether to re-elect Jair Bolsonaro, whose response to COVID-19 has been heavily criticized by public-health researchers. Evidence suggests that Brazil was a COVID-19 epicentre, exporting the virus beyond its borders and experiencing terrible loss of life within them. But with one in three Brazilians unable to afford to eat properly last year, food security and economic inflation could prove to be more urgent issues for voters than pandemic concerns.

Nature | 5 min read

Plan to save ‘drowning’ Pacific atoll islands

Political leaders from Pacific atoll island nations whose very existence is threatened by climate change have launched a global partnership aimed at protecting the sovereignty and rights of their countries. The Rising Nations Initiative was launched last week, on the sidelines of the United Nations General Assembly meeting in New York City. Tuvalu Prime Minister Kausea Natano told the assembly that rising sea levels are harming everything from crops to infrastructure, driving Tuvaluans to emigrate. “This is how a Pacific atoll dies,” Natano said. “This is how our islands will cease to exist.” So far, the United States, Germany, South Korea and Canada have supported the initiative.

Associated Press | 6 min read

Features & opinion

Tracking a variant to a single building

Virologists, environmental biogeochemists and city workers have teamed up to trace a heavily mutated variant of SARS-CoV-2 through the sewers in Wisconsin. Eventually, they traced the lineage to waste water from a single business with fewer than 30 employees, although the person carrying the virus has not been identified. The variant is one of thousands that are probably circulating globally, and there is no evidence that it is spreading. But tracking cryptic lineages can help to treat people who might be harbouring an infection without knowing it, reduce the chances of it spreading and possibly help to forecast broader trends in SARS-CoV-2 evolution.

Nature | 8 min read

Time to clear the air

COVID-19 has refocused our attention on what pioneering nurse Florence Nightingale called “the very first canon of nursing”: clean indoor air.

Many respiratory viruses, including those responsible for COVID-19, flu and the common cold, are spread through the air.Air can be contaminated with volatile organic compounds released by everyday items, such as air fresheners and furniture.Cooking can release harmful particles.The air we breathe out can impair us: research has found that students’ cognitive performance falls when carbon dioxide concentrations rise.

Open windows, adequate ventilation and ultraviolet sterilization all have potential to help. And consumer-product regulation could help to stop some air pollution at the source. Lasting improvement, say scientists, will require broad expertise. “What I learnt [during the pandemic] is that the only way forward is to work together with all the disciplines that are involved, the aerologists, the epidemiologists, engineers and the medical people,” says indoor-environment engineer Marcel Loomans.

Chemistry World | 15 min read