Indoor air pollution from cooking, cleaning and materials is a growing concern. Back in 1989, a NASA study found that plants put in sealed rooms could reduce the levels of pollutants(污染物), some of which can cause cancer.That finding led to the widespread notion that adding houseplants to rooms will lower levels of indoor air pollution, but later studies suggest that the effect is too small to make a difference in people’s homes.

So, Stuart Strand at the University of Washington in Seattle decided to enhance the pollution-reducing power of golden pothos(绿萝) by adding a rabbit gene for a liver enzyme(酶)that breaks down a wide range of pollutants. This approach boosted the effect several times. But even so, to make a meaningful difference, Strand concluded that a fan would be needed to move air over the plants.

Now, a start-up company called Neoplants has created another GM pothos. It has two added genes from bacteria as well as extra copies of some of the plant’s own genes. This enables it to break down certain harmful air pollutants, the company says.

Tests done in cooperation with the University of Lille in France suggest that the plants are 30 times better at removing these air pollutants than the best plants tested by NASA, says Patrick Torbey of Neoplants. The firm released a paper last week describing its work, but hasn’t submitted it to a scientific journal.

“This new paper looks pretty good,” says Strand. It isn’t possible to directly compare the effectiveness of his GM pothos with the Neoplants one as different tests were done, he says.

It remains unclear whether Neoplants’s pothos will make any difference in an actual home. But Torbey says the company is setting up a research facility near Paris that will include two “bedrooms” to test this.

A new study has found that ride-sharing services result in much more pollution than other kinds of private and public transportation. Ride-sharing trips also draw passengers away from more environment friendly methods of travel, like public transportation, walking or biking, the study found.

Several studies in recent years have suggested that ride-sharing services like Uber and Lyft can worsen traffic problems in cities. The new study represents an attempt to center on how ride-sharing services affect pollution.

Overall, the researchers reported that ride-sharing trips now "result in a 69 percent more climate pollution on average than the trips they replace." The study notes that the same passengers could have chosen to travel by bus, train, bike or on foot.

One of the big reasons they give for this result is that ride-sharing vehicles are often driven with no passengers in the car. This happens when drivers are either waiting for rider requests, are on the way to pick up passengers. This situation, known as "deadheading," takes up about 42 percent of all ride-sharing driving activity, the study found. The researchers said that deadheading results in about 50 percent more carbon dioxide than one person driving in a private vehicle.

Both Uber and Lyft have said in the past that most studies on the subject overstate (夸大）the effects of their services on pollution. Uber told Reuters news agency in a statement it had no comment on the latest report and that the study made misleading claims about ride-sharing. Meanwhile, the company said it would work directly with cities to address climate changes, promoting sharing trips and other means of transportation.

Avoid the supermarket shelves piled with cheese, cupcakes and pies. That is the message of an analysis that found these items are the worst when looking at both nutritional and environmental impacts of thousands of food and drink products sold in the UK and Ireland. So far, most studies have focused on the environmental impact of goods such as beef or beans, rather than tofu and other products that shoppers often buy. Where research has focused on such products, it has usually been for a small number of them.

In a bid to bridge the gap, Micheal Clark at the University of Oxford and his colleagues analyzed more than 57,000 food and drink products sold in the UK and Ireland. The team took the ingredients (成份) data from eight retailers (零售商), including major supermarkets Tesco and Sainsbury’s. However, precise figures on how much of each ingredient is in each product were only available for around a tenth of them. To estimate the rest, Clark and his colleagues trained an algorithm (算法) on the known products and used it to predict the composition of the unknown ones. Finally, the team linked all the ingredients to an existing database of environmental impacts, including emissions (排放), land use and water stress.

The results may come as no surprise: meat, fish and cheese products had highest environmental impact while fruit, vegetables, bread and sugary drink products had the lowest burden. Clark admits that none of this is exciting, given what we already knew from past research. “What is important is that you can start getting these impact estimates for products that people are purchasing, which then has a lot of effects,” he says.

One of those is eco-lables, which can help consumers to make greener choices. However, retailers have struggled in the past with the challenge of the large number of food. Clark is thinking about how to eventually turn the data into an app that could be used either by shoppers or by retailers wanting to reduce their environmental impact. “We’ve made that information available in a way that means people can start making informed decisions,” he says.