Blue whales eat up to 10 million pieces of microplastic every day, research estimated Tuesday, suggesting that the pollution causes a bigger danger to the world’s largest animal than previously thought.

A US-led research team put tags on 191 blue whales that live off the coast of California to observe their movements. “It’s basically like an Apple Watch, just on the back of a whale,” said Shirel Kahane-Rapport, a researcher at California State University, Fullerton, and the study’s first author.

The whales mostly fed at depths of between 50 to 250 meters, which is home to the “greatest concentration of microplastics in the sea,” Kahane-Rapport said. The researchers then estimated the size and number of mouthfuls the whales had daily, modeling three different situations. Under the most likely situation, the blue whales ate up to 10 million microplastic pieces a day. Over the 90 to 120 days’ annual feeding season, which represents more than a billion pieces a year.

The largest animal ever to live on Earth is also likely the biggest microplastic consumer, eating up to 43.6 kilograms a day, the study said. While it is easy to imagine whales sucking (吞没) in vast amounts of microplastics as they ate, the researchers found that was not the case.

Instead, 99 percent of the microplastics entered the whales because they were already inside their prey (猎物). “That’s concerning for us,” Kahane-Rapport said, because humans eat that prey. “We also eat sardines,” she said, adding that “krill (磷虾) is the basis of the food web.” “Previous research has shown that if krill is in a tank with microplastic, they will eat it,” Kahane-Rapport said.

Now that the researchers know how much microplastic is being consumed by whales, next they aim to determine how much harm it could be doing. “The quantity defines the poison,” Kahane-Rapport said.

Light pollution is a significant but overlooked driver of the rapid decline of insect populations, according to the most comprehensive review of the scientific evidence to date.

Artificial light at night can affect every aspect of insects' lives, the researchers said. "We strongly believe artificial light at night — in combination with habitat loss, chemical pollution, invasive species, and climate change — is driving insect declines,” the scientists concluded after assessing more than 150 studies.

Insect population collapses have been reported around the world, and the first global scientific review published in February, said widespread declines threatened to cause a "catastrophic collapse of nature's ecosystems".

There are thought to be millions of insect species, most still unknown to science, and about half are active at night. Those active in the day may also be disturbed by light at night when they are at rest.

The most familiar impact of light pollution is moths (飞蛾) flapping around a bulb, mistaking it for the moon. Some insects use the polarisation of light to find the water they need to breed, as light waves line up after reflecting from a smooth surface. But artificial light can scupper (使泡汤) this. Insects are important prey (猎物) for many species, but light pollution can tip the balance in favour of the predator if it traps insects around lights. Such increases in predation risk were likely to cause the rapid extinction of affected species, the researchers said.

The researchers said most human-caused threats to insects have analogues in nature, such as climate change and invasive species. But light pollution is particularly hard for insects to deal with.

However, unlike other drivers of decline, light pollution is relatively easy to prevent. Simply turning off lights that are not needed is the most obvious action, he said, while making lights motion-activated also cuts light pollution. Shading lights so only the area needed is lit up is important. It is the same with avoiding blue-white lights, which interfere with daily rhythms. LED lights also offer hope as they can be easily tuned to avoid harmful colours and flicker rates.

A strong sense of smell is a key component of a healthy and enjoyable life. Yet our sense of smell is in decline as a result of an unnoticed threat to our health: air pollution.

Scientists are finding that anosmia, a loss of the sense of smell, is becoming a widespread problem among people of all ages exposed to PM2. 5 pollutants constantly, which are tiny particles (微粒) that can enter our bodies with every breath we take.

The reason, they suggest, is that the olfactory bulbs (嗅球), which are located in our noses and packed with nerve endings, are affected by exposure to air pollution. The tiny particles cause illness either in the bulbs themselves or in the brain, impacting our sense of smell over time, “Our data show the risk of developing anosmia with constant particulate pollution is 1.6 to 1.7 times higher,” says Ramanathan, a doctor at the Johns Hopkins School of Medicine, America.

Ramanathan is an author of a recent study of nearly 2,700 patients, a fifth of whom had anosmia despite many of them being non- smokers.’ When he and his colleagues looked into the backgrounds of the affected patients, they found most of them lived in neighborhoods with significantly higher levels of air pollution.

The findings prove other studies with similar findings. One of these studies, conducted in a town in Italy, found that more than 200 teenagers and young adults between the ages of 15 and 25 suffered olfactory damage as a result of exposure to NO₂, a common component in traf-fic emissions. “This is alarming as olfactory loss affects patient safety, well-being, and it is a predictor of poor health,” says Ramanathan.

Yet the loss of a sense of smell is a condition that is often overlooked though it can bring about numerous health problems. A sense of smell is linked to memory as well and life is a lot less fun without it. “People don’t remember what the pastry that they ate in childhood looked like, but they remember what the shop smelled like,” says Ramanathan.