For hundreds of years, researchers have been trying to answer what kinds of things have an impact on people’s emotions（情感）. How you feel is controlled by many things. Your emotions can be influenced by your personality, by the actions of others and by events around you. In addition, maybe you really don’t know your emotions can be affected by the weather as well.

People often say they feel pretty good when the sun is shining and bad when it is cloudy.

As a matter of fact, sunlight makes us feel good. When sunlight shins our skins, our bodies produce a vitamin. Vitamins are natural chemicals (化学物质) which we all need to stay healthy. Sunlight helps our bodies produce vitamin D and it can help our bodies to make a special chemical. This special chemical affects our brains(大脑) and makes us feel happy.

For example, there are long, dark winters of little sunlight in Sweden and Norway, so many people in these countries often feel sad. Without much sunlight, their bodies produce less vitamin D. Without enough vitamin D, their bodies make less of this special chemical which makes them feel good.

In order to help the people in these countries feel better, special “sunrooms” with artificial(人造的) lights have been built. People can go there and get “sunlight” for an hour or two!

The weather can also affect people’s emotions in other ways. Hot weather can make people angry because people feel uncomfortable when they are hot. In the same way, rain can make people angry because being wet can be unpleasant. As you can see, the weather can have an effect on the chemicals which control our brains. Through these ways, the weather can influence our emotions. Sadly, while the weather can change us, we can hardly change the weather.

Breathing dirty air can cost someone’s lifespan (寿命) months—even years, a new study finds. Worldwide, air pollution lowers average lifespans by a year. Scientists shared their new findings in Environmental Science & Technology Letters.

Air pollution (污染) has been linked to many health problems. Most earlier studies have looked at how tiny air pollutants affected rates of illness or death. But now an environmental scientist, Joshua Apte, is going even further. He works at the University of Texas, Austin. He together with his team is looking at life expectancy, hoping to make the threat easier to understand.

PM 2.5 is what scientists call tiny particles of pollution in the air. Higher levels of PM2.5 can cause health problems and cut months, if not years, from the average lifespan. This analysis shows pollution affects life expectancy in different parts of the world.

The World Health Organization (WHO) recommends limiting PM 2.5 to 10 micrograms (微克) per cubic (立方) meter of air. Apte’s group used data to try to find how this low level would help people. But meeting the WHO standard won’t get rid of health damage from dirty air. That’s because even below 10 micrograms per cubic meter pollution still causes huge risks.

Reducing air pollution could increase life expectancy. The scientists also compared how other threats shorten life spans across the globe. These risk factors included smoking and cancer.

These results show that in poor countries, cleaning up dirty air could greatly increase lifespans. It could have as big an effect as cleaning up drinking water, or curing lung cancer. However, in wealthier countries air pollution shortens life expectancy by less than half a year. All forms of cancer, in fact, shorten the average life expectancy by more than 3.5 years. “Knowing this can really help people or policymakers, decide where to spend their money.” says Kirk Smith.

British chip maker Walkers is being flooded with mail deliveries of its own packaging. An online petition (请愿) with more than 312,000 signatures so far urges signers to mail their empty chip plastic bags to Walkers as an act of protest against the bags’ non-recyclable design.

As petition organizer Geraint Ashcroft explained, the majority of chip packets, made from metallized plastic, are not recyclable and have been found fully undamaged up to 33 years after consumption. The UK alone consumes 6 billion bags of chips a year, and Walkers turns out 11 million bags daily. Ashcroft wrote, “At today’s consumption rate in 33 years’ time, there will be 200 billion packets either sent to landfill or polluting our oceans. Many will be eaten by animals fish or birds leading to a slow death.”

Mailing the bags to Walkers is a way to hold the company accountable for its packaging and to pressure it to come up with a better design. Because Walkers has what’s known as a’Freepost’ address,the Royal Mail postal service is obligated (有义务的) to deliver anything that is addressed correctly — even if it’s an empty chip bag. But it is controversial. Royal Mail isn’t happy about it,asking people to put their chip bags in an envelope to help with ease of delivery. Critics on Twitter question the logic of buying a product in order to protest against its producer and suggest that giving up chips altogether would improve one’s health as well as the environment.

Walkers issued a statement on Wednesday, saying it will make its packaging plastic-free by 2025.“We have received some returned packets and recognized the efforts being made to bring the issue of packaging waste to our attention. The returned packets will be used in our research as we work towards our commitment of improving the recyclability of our packaging.”