2 . Carried by the wind, dust particles (微粒) from places such as the Sahara Desert can float halfway around the world before settling to the ground. As the plastics abandoned by humans break down into tiny pieces in the environment, they, too, travel through the atmosphere. Now scientists are a step closer to understanding how these microplastics travel in the globe — both locally and on long-distance flights.

Researchers spent more than a year collecting microplastics from 11 national parks and wilderness areas in the western U.S. They examined the particles that settled on dry days and those that fell along with rain or snow. In addition to making clear how microplastics move around, the results, published on Thursday in Science, reveal the seriousness of the problem: more than 1 million kilograms of microplastics — the weight of 120 million to 300 million plastic water bottles — fall on protected lands in the country’s western region each year.

The new findings add to scientists’ concern over microplastic pollution’s potential impacts on the environment and human health. “We’re not supposed to breathe in this material,” says Steve Allen, a microplastics researcher at the University of Strathclyde in Scotland, who was not involved in the new study. “Plastics in the environment “carry all sorts of pesticides (农药), heavy metals and all the other chemicals that we’ve made over time,” he adds. “They’re going to carry them directly into our lungs.”

Since their discovery in oceans in the 1970s, microplastics — which can be as large as a grain of rice or smaller than a particle of dust — have been found nearly everywhere researchers have looked: in cities, in Arctic snow, on remote mountaintops. Their presence in areas distant from the place where human live has pointed to them being carried by winds.

3 . Micro plastics can accumulate in the brains of mammals (哺乳动物) and even lead to behavioral changes,   according to a new study. This not only adds to evidence about the harm that micro plastics are doing to our environment, but crucially provides new insight into what they could be doing to our bodies.

Plastic pollution is a huge environmental concern. In particular, tiny pieces of micro plastic have been found everywhere from our oceans to the atmosphere. A team led by University of Rhode Island professor Jaime Ross wanted to learn about whether these micro plastics accumulate in the brains of mammals and the potential impact on behavior.

The researchers gave mice drinking water contaminated (污染) with different concentrations of micro plastics over a three-week period. They used mice of different ages to see whether the effects would vary in the younger or older mice.

Besides indications of changes in the mice’s brains, the team saw changes in their behavior, which were particularly apparent in the older animals. The behavioral changes are similar to symptoms you might expect to see in patients with dementia (痴呆) .

“These were not high doses of micro plastics, but in only a short period of time, we saw these changes,” Ross said in a statement.

“In this study, the micro plastics were delivered orally via drinking water, detection in tissues such as the gastrointestinal tract, which is a major part of the digestive system, was always probable,” Ross explained. “But the brain is protected by a boundary called the blood-brain barrier, which should make it harder to access. The team found that micro plastics had entered the brain’s tissues.”

“Once inside, micro plastics cause a decrease in the levels of a brain protein called GFAP,” Ross said. “A decrease in GFAP has been associated with early stages of some neurodegenerative diseases, including dementia and depression.”

Now that even the remotest parts of our planet are seemingly unable to escape contamination with micro plastics, more research like this, which seeks to better understand how human beings’ plastic habit could be coming back to bite us, is more urgently needed than ever.

4 . Global light pollution has increased by at least 49% over 25 years, new research shows. This data (数据) only includes light which can be seen through satellites, and scientists think the true increase may be significantly higher — up to 270% globally, and 400% in some areas.

This study shows not only of how bad light pollution has become as a problem of the whole world, but also that it is continuing to get worse, probably at a faster and faster rate.

The study highlights the “hidden impact (影响)” of the LED technology. LEDs send out more blue light than previous lamp technology, but satellite sensors can’t discover this blue light and so underestimate (低估) the level of emissions (排放物). The authors say the actual increase in the power sent out by outdoor lighting, and thus of light pollution, may be as high as 270%. “To take the UK as an example, if you pay no attention to the effect of the change to LEDs, you get the false impression that light pollution has recently weakened,” said researcher Dr Sanchez de Miguel. “However, it has really increased, very remarkably.”

Contrary to popular belief, the LED streetlights, while potentially providing some energy savings, has increased light pollution and also the impacts on flying insects (昆虫).

Ruskin Hartley, Executive Director of the International Dark-Sky Association, said, “Over the past 25 years, the use of LED lighting has been accompanied by rapid increases in light pollution all over the world.”

If no action is taken to change this trend (趋势), the impact on the natural environment will speed up, further worsening the biodiversity (生物多样性) crisis and wasting energy. Many studies have now shown that light pollution, from streetlights and other sources, can have major impacts on the natural environment. Such pollution is likely to have played a role in the huge decrease in insect populations.

6 . We often hear about how air pollution is changing earth temperatures. New evidence from a mountaintop in China now suggests that pollution can also change the amount of rain and snow falling in some places.

Usually, more precipitation ( 降水量) falls in mountainous places than in flat areas upwind (逆风的) from the mountains. In recent years, however, many mountainous areas in the USA have been getting 25 percent less precipitation than normal. Mountains that are downwind of cities have experienced the biggest drops.

Some British scientists have theorized that pollution moves from the cities into the mountains, affecting rainfall. To get answers, scientists from the Hebrew University of Jerusalem (耶路撒冷) turned to a mountain in China called Mount Hua. The mountain is 2, 060 metres tall and lies about 120 kilometers east of the Chinese city of Xi’an. Since 1954, meteorologists (气象学家) have been collecting details about rainfall, humidity, and visibility (能见度) in the area. Scientists compared rainfall on Mount Hua with rainfall in the nearest city, Huayin, on days with varying levels of visibility using these data. When the air was clear and people could see 20 km away, the scientists found that 65 percent more rain fell on the mountain than in the city. But when smoggy, allowing only 8 km of visibility through the haze (薄雾), the mountain received just 20 percent more rain than the city did. The new data support the theory.

Some scientists believe that there are other explanations for the numbers. For example, some believe that naturally occurring particles (颗粒) in the air rather than particles produced by pollution are affecting visibility. This is the first study to observe a connection between rainfall and changes in visibility due to air pollution. However, more studies are needed to confirm the link.

7 . In the first test of its kind in Europe, and only the second in the world, Belgian researchers tested 39 brands of straws (吸管) for the group of synthetic (合成的) chemicals known as poly-and perfluoroalkyl substances (PFAS). The straws are made from five materials — paper, bamboo, glass, stainless steel and plastic. PFAS were found in the majority of the straws tested and were most common in those made from paper and bamboo. They were not found only in steel straws tested.

PFAS are used to make everyday products, from outdoor clothing to non-stick pans, resistant (抵抗to water, heat and stains. They are, however, potentially harmful to people, wildlife and the environment. They have been related to a number of health problems, including lower response to vaccines (疫苗), lower birth weight, thyroid disease, liver damage, kidney cancer and testicular cancer. They break down very slowly over time and can last thousands of years in the environment, a property that has led to them being known as “forever chemicals”.

A growing number of countries, including the UK and Belgium, have sopped the sale of single-use plastic products, including drinking straws, and plant-based versions have become popular. The PFAS concentrations (浓缩物) were low in them and, bear in mind that most people tend to only use straws occasionally, bringing a limited risk to human health. However, PFAS can remain in the body for many years and concentrations can build up over time.

It isn’t known whether the PFAS were added to the straws by the producer for waterproofing or the PFAS were the result of contamination. Potential sources of contamination include the soil the plant-based materials were grown in and the water used in the production process. However, the presence of the chemicals in almost every brand of paper straws means it is likely that it was, in some cases, being used as a water-resistant coating, say the researchers.

8 . A new study has found that light pollution is making the night sky brighter and the stars dimmer (暗淡的). The study examined data from more than 50, 000 citizen star watchers across the world, It found that man-made, or artificial lighting is making the night sky about 10 percent brighter each year. Data for the study was collected from 2011 to 2022.

The result was a much faster rate of change than scientists had estimated in the past. As cities expand and put up more lights, a “skyglow” is created in the sky. Skyglow is a term scientists use to describe light that becomes more intense. The research team gave an example to explain the result. If a child is born where 250 stars can be seen on a clear night, by the time that child turns 18, only 100 stars will be seen.

Past studies involving artificial lighting used satellite images of the Earth at night. They had estimated the yearly increase in sky brightness to be about 2 percent a year. But the satellites used are not able to identify light with wavelengths toward the blue end of the spectrum (光谱) — including light given off by energy-effective LED bulbs. The researchers noted that more than half the new outdoor lights put in across the United States during the past 10 years have been LED lights. The satellites are also better at finding light that gets spread upward like a spotlight than light that spreads out from side to side, Kyba said.

“Migratory songbirds normally use starlight to orient (确定方向) where they are in the sky at night,” said Georgetown University biologist Emily Williams. She was not part of the study. And when sea turtle babies hatch, they use light to orient toward the ocean — light pollution is a huge deal for them.

Falchi, the physicist at the University of Santiago de Compostela, said part of what is being lost is a universal human experience. “The night sky caused the generations before ours to have exciting new ideas or made them want to create something, especially in art, music, science and literature,” he added.

9 . According to a new study, human noise is a “major global pollutant” that harms a wider range of animal life than we tend to think. Published in the journal Biology Letters, the study suggests noise pollution not only harms lots of animals, but also threatens the survival of more than 100 different species.

Lots of species rely on sound for communication, for example, including many amphibians, birds, insects and mammals which use sound for vital business like finding mates or warning about predators (捕猎者). If noise pollution drowns out enough of these messages. it can threaten survival and the stability of their populations.

On the other hand, noise pollution can make it harder for some predators to find food Bats and owls rely on sound to hunt, for instance, which may not work if noise pollution drowns out the sounds of their prey like insects and mice. Even if noise pollution is mild, it might still force them to spend more time and energy searching for food, which could be enough to cause a decline.

Noise pollution is a well-known risk for whales and dolphins, but it threatens other sea animals, too. The researchers cite fish larvae, which are easily drawn to the sounds of coral reefs (珊瑚礁). This is how they find suitable habitats, but if their journey features too much noise from ships and other human sources, more fish larvae may get lost or move into wrong reefs, potentially reducing their lifespan.

Similarly, noise pollution influences the way animals migrate (迁徙), which in turn can have chain effects for ecosystems along migration routes. Some migrating birds avoid areas with noise pollution, the researchers note, which may change not only where they travel, but also where they establish long-term homes and raise their young. Many ecosystems and non-migrating species have come to depend on the arrival of migrating birds, and many others may be unprepared for their sudden absence, so this could cause a series of ecological changes.

“Noise must be considered as a global pollutant and we need to develop strategies to protect animals from noise for their livelihoods,” says Kunc, the lead author of the study.

10 . In the west of the Greek capital Athens, the fish market of Keratsini is busy early in the morning, with trucks waiting nearby to be loaded with fishes. But on his fishing boat, Arapakis sorts out something different—bottles, boots, plastic pipes and fishing nets, all dragged from the bed of the Aegean Sea.

“We are swimming in plastic,” said Arapakis, whose family has fished for five generations. “By 2050, there will be more plastic than fish in the sea,” he said, as recent reports noted.

That morning’s plastic catch weighed “about 100 kilograms,” said the founder of Enaleia, a nonprofit that encourages fishermen to collect marine (海洋的) waste caught in their nets. Since its establishment in 2018, it has worked with more than 1,200 fishermen in Greece to raise concern over the degradation of the marine environment.

Active in 42 ports throughout Greece, Enaleia provides fishermen with large bags for marine waste that they can put in garbage cans once back at port. For every kilogram of plastic they deliver, they receive a small amount of money, which is enough for a drink. Since October, fishing crews have dragged out 20 metric tons of plastic and old fishing equipment each month. Nearly 600 tons have been collected over the last five years. The collected plastic is transported to a recycling plant in the industrial area of Megara near Keratsini, to make new products such as socks, swimwear or furniture.

Arapakis said he went about the cleanup project after a trip to Greece’s Cyclades islands, where he saw fishermen throwing the waste gathered by their nets back into the sea.

Arapakis is convinced there has been a “mentality change” among Greece’s fishermen. “Previously we caught large quantities of plastic, but we only kept the fish. All waste was thrown into the sea,” said Mokharam, team leader on the Arapakis family’s boat. “The project brings practical benefits for fishing boats. In the past, the anchor was often caught by waste, especially nets, and the engine would go out. But now things have changed,” he added.