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Shutting Down Pollution | Earth Wise

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With much of the country shut down as the coronavirus forces people to stay at home, there has naturally been a drastic reduction of traffic on roads and highways.   And with that decrease, there has been a dramatic reduction in pollution as well.

A satellite that detects emissions in the atmosphere linked to cars and trucks has observed huge declines in pollution in major metropolitan areas such as Los Angeles, Seattle, New York, Chicago, and Atlanta.

Los Angeles is infamous for its rush-hour traffic but that has pretty much ceased to exist. Similar changes can be seen in the San Francisco Bay Area, where nearly 7 million residents have been ordered to shelter in place.  New York City is less dependent on car travel than in other metro areas, but the shutdown of office buildings, schools, and restaurants has nonetheless resulted in a substantial reduction of traffic on the streets of the city.

While this sudden decline in air pollution over U.S. cities has some near-term health benefits, those benefits are likely to be fairly minor in the big picture.  When the coronavirus outbreak subsides and people are allowed to leave their homes and go back to their normal lives, air pollution will most certainly rebound to previous levels.  In any event, studies have shown that long-term exposure to air pollution has a larger impact on public health than any transient events.

Having much cleaner air for a while is certainly a good thing, but this shutdown is not a sustainable way to reduce air pollution and the long-term effects of the coronavirus crisis will certainly not be positive.

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Traffic and Pollution Plummet as U.S. Cities Shut Down for Coronavirus

Photo, posted March 15, 2020, courtesy of Tom Collins via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Falling U.S. Carbon Emissions

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Reducing carbon emissions is a goal embraced by nearly every country in the world, but actually accomplishing it isn’t easy. It is true that renewable energy sources are playing a growing role in energy systems, but counterbalancing that trend is growing energy demand, especially in developing countries.

Here in the US, energy-related CO2 emissions actually went up nearly 3% in 2018 compared with 2017.  But the US Energy Information Administration is now forecasting a 2% drop in emissions this year.

The main reason energy-related emissions are headed lower at this point is coal-fired power plant retirements.  More than 90% of the coal used in the US goes toward electric power and utilities are increasingly turning away from coal.

The rapid shift away from coal has mostly been due to the increasing use of natural gas.  Natural gas is not actually a clean and green fuel, but it is definitely less carbon-intensive than coal.  Overall, the total installed capacity of renewable sources – hydropower, wind, solar, geothermal, and biomass – has now actually surpassed the capacity of coal plants.  Given that renewables have in many places become the cheapest power option, there is little chance that coal has much of a future, despite efforts by the current administration.

The electric power sector is gradually moving away from all carbon-emitting sources – a trend that is being reinforced by legislation in many states.  The real CO2 emissions leader is petroleum, which accounts for nearly half of the total.  We have a long way to go to reduce emissions from the use of petroleum.  There are over 250 million cars and trucks on US roads and only a little over a million of them don’t burn fossil fuels.

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US energy-related CO2 emissions expected to fall this year, almost solely due to a drop in coal use

Photo, posted November 6, 2017, courtesy of Cindy Shebley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Making Roads From Ocean Plastic

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Like many other places around the world, India has a big problem with plastic waste.  Its 1.3 billion people each use an average of 24 pounds of plastic per year and much of it ends up in the Arabian Sea and Indian Ocean.

Fishermen in India’s southern state of Kerala have taken on the battle against plastic waste in the ocean by launching a campaign called Suchitwa Sagaram, or Clean Sea, in which they are collecting the plastic and bringing it back to shore.

In the first 10 months of the program, fisherman have removed 25 tons of plastic from the Arabian Sea.  Once the plastic waste reaches shore, it is fed into a plastic shredding machine.  As is the case for many of India’s plastic recycling schemes, the shredded plastic from the sea is converted into material that is used for road surfacing.

There are more than 20,000 miles of plastic roads in India, mostly in rural areas.  In fact, more than half the roads in the southern state of Tamil Nadu are plastic.  Such roads have become popular because they are more resilient to India’s searing heat.  The melting point of plastic roads is around 150 degrees Fahrenheit as compared to 122 degrees for conventional roads.

Roads made from recycled plastic are also cheaper than ones using conventional plastic additives.  A mile of plastic road uses the equivalent of a million and a half plastic bags and saves about a ton and a half of asphalt.  Overall, plastic roads are about 8% cheaper than conventional roads and create jobs for people in the fishing communities.

India’s plastic roads are a promising way to fight the problem of ocean plastic pollution.

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These Indian fishermen take plastic out of the sea and use it to build roads

Photo, posted April 25, 2016, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Weather-Responsive Traffic Signals

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We all spend time sitting at red lights – sometimes it seems like a whole lot of time.  There is a fair amount of science applied in the design of traffic signals that at least has the aim of easing congestion and improving traffic safety.

Signals in modern cities are timed using optimization models that analyze multiple factors including traffic volume and speed with the goal of safely getting as many vehicles as possible through intersections.  It sure doesn’t seem that way in many places, but that is the intent in any case.

But a real problem with these models is that they assume normal conditions including weather conditions.  In places that experience real winter conditions, the assumptions of traffic models fail.  If the road surface is covered with snow and ice and visibility is poor, variables like speed and stopping distances become very different.

Researchers at the University of Waterloo in Canada collected data from real-world intersections and ran computer simulations to determine the effects of adjusting traffic signal behavior in bad weather (as well as in the presence of other conditions such as accidents or construction.)  They found that such adjustments could reduce traffic delays by as much as 20%.   

Cities with computerized signal systems are already equipped to remotely and inexpensively adjust the timing of traffic lights.  To gain the benefits of smarter signals, there would need to be video cameras and a certain amount of artificial intelligence software that would be able to automatically tweak the timing of lights in response to traffic changes caused by weather, accidents or construction. 

It sounds like a great idea.

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Weather-responsive intersections could ease traffic congestion

Photo, posted September 22, 2009, courtesy of Tristan Bowersox via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Trees And The Future Of Cities

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The shade of a single tree is a welcome source of relief on a hot summer day.  But even a relatively small patch of woods can have a profound cooling effect.  A new study at the University of Wisconsin-Madison looks at the role trees play in keeping towns and cities cool.

According to the study, the right amount of tree cover can lower daytime temperatures in the summer by as much as 10 degrees.  The effects are noticeable from neighborhood to neighborhood and even on a block-by-block basis.

Cities are well-known to be hot spots due to the urban heat islanding effect.  Using trees to keep temperatures more comfortable in cities can make a big difference for the people who live and work there.

The man-made structures of cities – roads, sidewalks, and buildings – absorb heat from the sun during the day and slowly release it at night.  Trees, on the other hand, not only shade those structures from the sun, but they also transpire -or release water in the air through their leaves – which helps to cool things down.

According to the study, to get maximum cooling benefits, tree canopies must exceed forty percent, meaning that city blocks need to be nearly halfway covered by tree branches and leaves.  To get the biggest bang for the buck, cities should start planting more trees in areas that are already near the forty percent threshold.  But

trees can’t just be in parks.  They need to be in places where people are active.

If we want the places where we live to be more comfortable and resilient in a warming world, we need to plant more trees.

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Study suggests trees are crucial to the future of our cities

Photo, posted May 26, 2012, courtesy of Mislav Marohnic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Misconceptions About Electric Cars

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Tesla’s Model 3 was one of the best-selling cars in the United States last year, eclipsing all but a handful of sedans.  This was the first time that an electric car had that honor and is indicative of how electric cars are finally becoming mainstream.  A host of other new electric models from multiple manufacturers will be the entering the market over the next couple of years.

Despite all of this progress, there is still a great deal of misinformation about electric cars.  A new study commissioned by Volkswagen revealed some of the widespread misconceptions about the vehicles.

Some people believe that electric cars can’t be driven through puddles.  Nearly one in five people believe that electric cars slow down as the battery depletes.  Many people believe that electric cars are fundamentally less safe than gas-powered cars.

More generally, people are unaware of how far current electric cars can drive on a charge.  More and more models can go 200 and even over 300 miles between charging sessions.  People also don’t know how quickly cars can charge up either.  Fast chargers like Tesla’s Superchargers can add 200 miles worth of charge in about 20 minutes.  And people don’t know what it costs to charge electric cars.  In most places, it is only a fraction of what it costs to drive the same distance using gasoline.

Despite their limited knowledge about electric cars, the 2,000 people surveyed in Britain were positively disposed towards them with nearly 6 in 10 saying that they would like to own an electric car some day and would even consider one as their next vehicle.

Electric cars will become more familiar and less exotic as more and more of them are on our roads and highways.

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Major misconceptions prevent drivers from buying electric cars, study claims

Photo, posted April 6, 2018, courtesy of Brian Doyle via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

https://www.independent.co.uk/news/uk/home-news/electric-cars-misconceptions-battery-charging-safety-volkswagen-study-results-a8700536.html

Making Cities Cooler

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Cities are particularly miserable during heatwaves.   With lots of concrete and asphalt surfaces, they soak up lots of heat and re-radiate it.  Lots of tall buildings block cooling breezes.  Factor in car exhaust and heat from air conditioners and it all adds up to the urban heat island effect.  Cities can be several degrees warmer during the day and as much as 20 degrees warmer at night.  All of this extra heat is not just a comfort issue, it is a serious health problem.

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V2V And Safer Cars

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Automated cars are coming, but they face many challenges in sharing the roads with human drivers.  The on-board sensors in these cars are very effective in many ways, but they cannot see around corners or see through buses or trucks.  They won’t know if six cars ahead, someone has slammed on their breaks leading to a chain-reaction collision.  Of course, human drivers have the same problems.

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Cooling Cities With White Roofs

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The phenomenon of urban heat islands has been well known since the 19th century.  The materials from which city buildings and roads are made reflect much less solar radiation and absorb more of it than the vegetation they have replaced.  The absorbed energy is then radiated in the form of heat into the surrounding air making cities warmer.

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Turtles Delay Flights

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Recently, we talked about the problems New York’s native turtles have during their mating season as they cross roads and highways seeking places to lay their eggs.   The state Department of Environmental Conservation even issued recommendations for how people can help turtles avoid getting crunched by cars.

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Save The Turtles

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New York is home to 11 native species of land turtles.  Many of the species can’t breed until age 10 and then they lay just one small clutch of eggs each year by digging in a suitable patch of sandy soil.  As a result, breeding females are at a premium for the welfare of the species.  Overall, turtles are on decline in the Empire State.

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Size Matters

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One of the crowning achievements for wildlife protection in the US was the establishment of the National Wildlife Refuge system in the 1930s, when the populations of waterfowl were perilously low. Refuges provided breeding and migratory habitat that has allowed a remarkable recovery of many species of ducks and geese.

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