news from around the world as well as push notifications for any breaking news and if you will part of a news story you can also use the d.w. app to send us photos and videos of what's happening the watching news from ballin up next 1000 special i'm told me a lot of fun thanks for joining us. combating the corona pandemic. where does research stand. what are scientists learning. background information and news. hour carona update. from the 19 special next on d w. w's crime fighters are back africa's most successful in radio drama series continues this season the stories focus on hate speech cholera

prevention and sustainable truckle production. all of a sow's are available online and of course you can share and discuss on africa's facebook page and other social media platforms. crime fighters to news now. how dangerous is the air around us. every time we speak every time we laugh or saying. we admit particles and once they're there and they linger we know that this is a key way that corona virus can spread. scientists are still sussing how dangerous these doses of airborne virus can be and what we can do to avoid them. opening a window is one way to keep the air fresh but by keeping the air moving with systems

like air conditioning or we decreasing the risk or merely spreading it. what do we need to do to breathe easily indoors. and this is the covert 19 special who are welcome to the show and. open the window it's the one piece of advice we're all hearing now that's a bit more complicated in the winter doesn't work in all rooms and certainly doesn't work on airplanes they've used in industry says cabin air is sufficiently filtered and circulated to some experts say questions remain. for air travelers social distancing already starts to get difficult at the boarding gate and it gets even trickier on the plane spacing out just isn't possible unless you can afford to buy an extra seat. with only 50 centimeters distance between each person the risk of infection is obvious and healing the droplets in aerosols from an

adjacent passenger seems unavoidable scientists have long been aware of the dangers of infection on planes mostly because of studies of other coronaviruses air is not displaced in aircraft inlets in l. it's hard to small for that cabin air can only be mixed. over at the hamburg university of applied sciences professor dr schulte says viruses may stay in the cabin air for up to 15 minutes exposing passengers to infection risk. going to the aviation industry makes 3 claims firstly filters an aircraft might be air as clean as an operating room and secondly the air is completely exchanged every 2 to 3 minutes thirdly the air only moves from top to bottom in the cabin all 3 are just not sure. it could be that current safety standards and filtration techniques are not as good as many may think meaning the possibility of catching coronavirus when

flying could be more up to chance than anything else. let's take a closer look at ventilation and the virus joining me now is paul linden he's professor of fluid mechanics at cambridge university paul it's good to have you on the show sort of the obvious question winter is approaching in northern in the northern hemisphere what's the best thing that someone should keep in mind about ventilation in rooms well it's obviously a challenge the winter because. you have to see is to close up buildings and ventilation is reduced to keep warm so the best thing to do is to make sure that as much ventilation as possible is achieved open a window if you possibly can. and if you have a mechanical system make sure as much fresh air coming in as possible what about fans what if i just have fans that are standing around the room does that help keep things ventilated is that help me at all no it doesn't it will just mix up what's

already there and that's probably not the best thing because if there is virus particles in the air in the air and stood all around your chances of breathing them are increased so i wouldn't recommend using fans ok so the best option then it seems to be is to keep the window open even though it's when it's winter or least open a periodic lee. of course that's going to mean that people are going to be colder rooms are going to be colder is this really a choice now that we have between climate control and being safe with the virus is it such a black and white choice pretty much i would say it is that's right and. it's well known that during the spanish flu. classes in the u.s. even in the midwest in the winter were held outside so. i think it is a it is a tradeoff between staying warm and staying safe that's going to mean quite

a change for the industry the climate control. air conditioning industry. yes absolutely. and i mean conventional systems use a certain amount of research elated air and they supplement that with some fresh air when it comes to dr through the building and again you want to make sure that the proportion of pressure air is as high as possible and that will in a climate controlled situation mean of course more energy is used to keep that to warm that iraq. so it'll be a tradeoff they have between between energy costs and. the amount of fresh air that you can provide and then one of your studies you mention carbon dioxide of course being an indicator as well does this mean that we can expect that carbon dioxide as yours will be a more common feature in rooms yeah i believe that's

a very sensible thing to do carbon dioxide is essentially within a building produced by people exhaling. and so levels that are above the background outside values of about 400 something past a 1000000. indicated indicative of. its being in someone's lungs and then breathed out again and so measuring that gives you an estimate in fact you can relate the risk of infection directly to the concentration of carbon dioxide help me understand your picture when i enter room breathing speaking laughing with without a mask what am i seeing and what are you seeing if you're able to see these these plumes or whatever you call them. yes so from an individual you give off heat. every person gives off about 80 watts bit like

a blot fairly bright light though and that heat rises from your body in what we call a turbulent plume. and that will rise up to was the ceiling and you know that in most rooms the air in the ceiling is warmer than the air in the floor also plumes arise from equipment like a computer or other things and and when you breathe out you also agree that warm air and that warm air is directed of course. in different directions so if you breathe through your nose as directed downwards if you breathe if you talk and is goes nationals horizontally and of course it depends on sounds that you make some sounds inject air further and do you speak the further it goes so there's a very complex dynamical process going on and it's invisible that's quite right we have techniques that make it possible to visualize this and we use those techniques

which essentially look at the way the refractive index of the air changes it's a bit like watching the a shimmer above a toaster you look at your toaster one that you see that is the same process and we can visualize that we can see where this goes and what we do see is that if you wear a mask for example that the air that you exhale even when you're speaking we're even blocking and coughing tends to basically leak around. the edges of the last night's sleep around the nose where it doesn't it properly and that then gets carried up with the plume in your body and that's a good thing so that so wearing a mosque generally confines your breath to to be taken up with the hot air rising from you is more complicated if you're. the around on the other hand because then you have a white behind you just as you would. a way behind a ship and and that way you carry your breath in the wake behind you

so you can spread it around quite significantly so those flows are much more vigorous than the flow produced by your ventilation system and that your very close to say an open window you probably don't perceive the around you. so those floods a real run to the weak the flow from your heat from your body when you speak when you breathe in and out there much stronger and then and so it's a complicated interaction between those flows and the general tendency imparted to rise and into be taken in and out through whatever openings you have in you in the building or i will have to leave it there for now it sounds like a fascinating time to be a professor of fluid mechanics paul linden joins us from regina versity thank you very much thank you. and now it's time for your questions it's the part of the show where our science correspondent derek williams answers the questions you've posed that tore you tube channel over there.

if a number of vaccines come out of the same time would it homy to take multiple different vaccines. in light of how quickly things are moving on the vaccine front this is an important question and for example there have been reports that china is apparently already giving tens of thousands of doses to people there of vaccine candidates that haven't yet completed widespread safety and efficacy testing observers are seriously alarmed by that because it sets the stage for a range of frightening possible scenarios what happens for instance if the vaccine doesn't prevent infection as well as hoped and and those people have to be vaccinated again at some point with other candidates could that be dangerous for them the short answer is once again we don't know but possibly vaccines can have adverse effects even when just one is administered that's why they're tested so

widely before being approved for the general public and with dozens of different candidates out there based on a number of different platforms there are a lot of possible combinations with the potential to go wrong if people start being given more than one vaccine or or given them in a haphazard undocumented ways until we actually do it there's no way to rule out that giving vaccines in combination or in a series could pose a danger which is why it's best to exhaustively check every vaccine candidate for safety and efficiency in advance so that in a best case scenario we only have to vaccinate everyone once. or science correspondent williams there and before we let you go here's another look at how people are adapting to life in the pandemic in this case by socially distancing within

a crowd. of music has returned to rio de janeiro but many dance floors and open air concert spaces that feature spaced out boxes of up to 6 people each music fans there say it's important for their mental health to be able to let loose well hopefully staying safe. and that's it for ark over $1000.00 special we hope that you stay safe and join us next time it's watching. eke out africa and baby boom for uganda is not in. the primates have taken advantage of the peace and quiet of the current virus lock down to produce a particularly large number of offspring residents in the neighboring villages are thrilled to may hope that these we're animals will soon attract new tourists again the eco africa. on t.w. . 11 from must use really become

a shoe. hell need more just. the beginning of the end of camel based products. but which alternatives work and which ones pay off the. new ideas from the global market made. greater use for me in return for this for you. beethoven as for health. beethoven. beethoven is truth.

beethoven is trying to. be tough it is for. beethoven 202250th anniversary year long do you. know. it's no secret that our planet's resources are dwindling and that's why when i am buying program would like to see ideas on how you can protect and support nature welcomes the coffee i'm now in lagos nigeria and a one welcome for me too so glad you could join us today i am sundra to nobody coming to you from kampala here is what is coming up shortly.

and. mountain gorillas ah the pride of a country here in uganda these wonderful and on the most drum many visitors which helps the economy but the core of. the tourism industry hot so a women's initiative to the windy impenetrable national park where the. attraction has come up with other ways of income and that is continuing even though the park is now once again open to visitors but the women aren't the only ones who read

a good use of their time doing this pandemic. for. springs in the past 2 months the oldest. members. are used to the sight of humans so. so they are in just a welcome addition. of joy for the people. with. us it is so strange because. in our history. the good news for.

profits from. the coronavirus looked down much broached tourism to a standstill depriving many local women of the way to. these women have been home for fix months with no walk almost 7 months. because uganda has opened. them to them it means they want to that i ming on income right for a woman or for us have uses his bike she was around the national park some of the women just had to learn how to ride a bike themselves but that too as i'm now in big demand rights for women was founded as a goal by. no employees of our 300 women from villages in the area. women but using that mountain base those we thought maybe

torso calm and actually used the mountain by schools hire them and then demanded liquids of women and benefits to providing to us as help the women and other locals to recover to protect nature and wildlife many know watch out for america to prevent the apes from being exploited it's sort of a common human perspective that twat doesn't benefit you is useless. that's how most of the people in the. conservation areas it is and if there is a benefit of one of them. then it seems. it's not moving up but that ended abruptly in march there were no more tourists to rinse the mountain bikes visit workshops or buy handicrafts. so instead the women started making face masks for companies and organizations in uganda as well as for exports abroad.

and we have. so when we get it here we trade. these women in. just one and we started for this community of women with the help of donations they. also helps keep the charity going plus people need to eat even when there's no money coming. become self-sustaining slowly get football in here take it to their women who are on the other side walking and then leave so i am bringing their money out to us that are coming to the women working in the 5. intersections are being lifted. and. soon the women with the bikes

and with. billions of the silver box and his family. have been born since the beginning to the day of conservationists these majestic primates that species. there were only $800.00 mountain lived all of them. run the democratic republic of congo fortunately the protective measure. has proved effective and their numbers have grown to over a 1000. did you know that some 1300000000 tons of food a west it every year one white in africa it is often down to a lot of infrastructure for preserving freshly rested food as a result on average $6.00 to $11.00 killers of food a west at. play here in developing countries what

a waste of resources sondra but in industrial nations the level of waste is 10 times greater retailers and consumers often toss out food just because it's no longer fresh now one company has found a way of extending the shelf life of fruits and vegetables using a method that doesn't harm the environment. the fruit and vegetables rotting in fields or during transportation to consumers. according to the un food and agriculture organization or f a o some 14 percent of food is lost after harvesting and before it reaches the market or retailer. if you go to a particular country or really you are likely to see varying levels of food losses and these you pending on the situation would go up even to 50 percent if you're talking about let's say fruits and vegetables for example if the from

a does not find a market for that particular food product in a timely basis now this is huge amount of food and if you you convert it into monetary 20 this is a lot and if you read it as well into the laws to the environment or the environmental impact that is also huge. when that happens water pesticides and resources used for transportation are all wasted some 7 percent of global greenhouse gas emissions can be traced back to food loss and waste the chief causes include problems with transportation and refrigeration. getting the produce from harvest to kitchen table is a race against time. a california based company appeals sciences might be able to help.

founder james rodgers and his team have developed a liquid that could extend the shelf life of fruits and vegetables. appeal is a little exactly like it sounds peel it we apply to the surface of fresh produce you can't see it you can't taste it you can't feel it but it slows down the factors that cause the fruit to age. it helps even without refrigeration appeal is a liquid coating that dries into a kind of edible skin. the coating helps the produce last up to 4 times as long that buys time time to transport the produce to store it and eat it before it spoils. appeal is based on limits and other natural compounds found in fruits and vegetables. they were extracted and blended into a tailor made solution. by combining them in the right ratios when they dry dry into an arrangement

that allows us to control the factors that cause fruit to age which are basically water going out and oxygen going in so same materials we're just teaching a new trick by finding the right formula to apply to different kinds of produce in order to give them the same kind of protection that you have a woman on a cucumber or on a. dutch wholesaler nature's pride some 120000 tons of fruits and vegetables a year they import from 59 countries especially latin america in rotterdam. the imported produce continues to ripen before it's sorted and shipped to the retailer . and waste is a common problem in the industry but the company hopes to minimize these losses in the future. in the way they actually bought it and they don't use it and that costs

money. so in the chain if we don't know in a way you don't spend that money wrongly with the people we can reduce food waste well 60 percent after we did a level. food that used to land in the trash can now be sold every day nature's pride treats 6 tons of avocados with appeal before sending them to supermarket shelves across europe. the main customers are in scandinavia germany and the netherlands. nature's pride is the 1st company in europe to use appeal. they're planning to start treating other kinds of fruits and vegetables soon. as saying is going by air by using a few we might give them the possibility go by boat and that is a forces they need and are safe so there's lots of opportunities. so far the new technology is mainly being used by large companies the smaller ones can't afford it but appeal says it's planning to change that with

a new business model it foresees retail chains in supermarkets paying for the technology for small producers and farmers to install. in return the retailers receive longer lasting produce farmers in places that haven't had access to national and international markets could also benefit. and so the opportunity is to be able to use appeal to reduce the transport station cost increase the quality so it's not a it's a way 'd for a small producer to grow something that's intrinsically valuable to collect some of that value. and that's exactly what would help producers in african countries appeal is currently setting up a facility in south africa for example. it's not just aimed at the export market but could also help reduce food waste in the country itself. but while extending the shelf life of produce will help it won't put an end to the waste problem. for

that transportation and refrigeration systems will also need to be improved and expanded. and consumers will need to stop throwing food away and start only buying what they'll actually eat. here you get a clue what's really going on. because africa . has been played out big. we introduce you to clever people and the latest solutions for the environment. simply amazing stories. africa. let's move to egypt now many. in the north african country are so isolated. a problem for residents on a tourism industry could provide

a solution and what egypt now has one of the world's largest solar plant it can't cover the needs of the country in the meantime smaller supply. to fill the gap let's take a look. around is a remote fishing village on the red sea and it's not on the national grid. until recently the only electricity here came from diesel generators. now a solar powered local grid provides electricity a ramp a clock enabling fishermen to store their catch safely. you know. when we can't fish we used to take them either 11 kilometers south to her mouth or more 16 kilometers north to busan. it was quite a long drive and the fish would sometimes go bad and start to smell. now that we

have electricity around the clock we have a freezer people come to us to buy fish and we save on time and travel costs. 100 kilometers to the north is marseille. it's a popular tourist destination the hotels here rely mostly on diesel generators for electricity. but that's not the case at the marseilles shakhtar a large where people come from all over the world to dive the owners here have invested in solar power but the system only provides electricity joining the day when it's.