By crunching data from satellites and ground monitoring stations, environmental scientists are creating maps and forecasts that reveal the scope of China’s air pollution problem in unprecedented detail. The big question is: Will all this data have any impact on environmental policy?

The maps show that China’s air pollution is beyond bad, it’s catastrophic. In Beijing, residents are responding to the ongoing “airpocalypse” by wearing heavy-duty respirator masks as they go about their daily business, or, increasingly, by never going outside. Fancy schools now feature domes that enclose their playgrounds and sports fields, and residential towers connect directly to underground malls and subway stations. 

At the time of this writing, Beijing’s air quality index is 159, which is actually a pretty good day for the megacity. True, the widely used EPA rating system calls anything above 150 “unhealthy,” likely to aggravate heart and lung conditions and to cause respiratory problems among the general population. But there have been days when Beijing’s air quality is literally off the charts, exceeding the “hazardous” rating that tops out at 500. 

A number of existing websites and apps provide real-time air quality info for worried city residents wondering if they dare cycle to work or open their windows. But precise data for air quality across the country has been hard to come by, and both forecasts and historical data have been lacking. A startup and a nonprofit, both hailing from the San Francisco area, are now addressing those gaps.

Carl Wang was born in Beijing, but has lived in the United States for the last decade, working as an air pollution researcher. Now he’s heading back to China as the founder of a startup that maps smog across the country at a 1-km resolution, and provides a 7-day forecast. Wang says his company, Gago Environmental Solutions, can create custom tools for China government agencies that will enable better management strategies.

Wang’s forecasts rely on proprietary calculations that combine pollution data with meteorological data. “Relative humidity, temperature, wind speed—all these play an important role in these calculations,” Wang tells IEEE Spectrum. Specific regional weather patterns require different calculations, he says.

His system uses pollution data drawn from three satellites and 1,400 ground monitoring stations. The satellites (two from NASA, and one from the Japanese space agency) use infrared sensors to map particles suspended in the atmosphere. The ground monitoring stations, run by the Chinese government, provide hourly readings of six major air pollutants that are used to create the air quality index. Among the six is the crucial PM 2.5, a measure of particulate matter less than 2.5 micrometers in size, small enough to penetrate deep into the lungs. All together, Wang says his system is crunching 30 to 40 gigabytes of data every hour.


Image: Gago Environmental Solutions
This smog map from Gago Environmental Solutions shows northern Beijing and its environs during a night in May 2015. The color scale shows levels of PM 2.5, with red being highest and blue being lowest.

The data from China’s monitoring stations is freely available online, but that hasn’t always been the case. Wang notes that a few years ago, a controversy erupted in China over the U.S. embassy’s monitoring of PM 2.5 and its very public tweeting of the measurements. The Chinese government initially declared this monitoring illegal and pressured the embassy to stop, but has since reversed its position. “Then, environmental data was considered national security issue, but now it’s totally different,” Wang says. 

Well, maybe it’s not totally different: In March, China’s government censors restricted access to an acclaimed documentary about China’s air pollution, Under the Dome. 

Wang is heading to China next week for meetings with local and national environmental agencies. His forecasts could not only alert a local agency about an upcoming “poor air quality day,” he says, but could also indicate the contributing sources of the problem. And that would enable it to take action. For example, a forecast showing high concentrations of carbon monoxide and soot, which are indicative of car pollution, could cause an agency to tweak its traffic control policies. “With our smog mapping product, they could use this policy tool more effectively,” Wang says.  

Another impressive display of data-crunching comes from the nonprofit group Berkeley Earth. This group started scraping hourly data from 1,500 air monitoring stations in China and adjoining countries in April 2014, and is now publishing maps and making its data archives available.

Elizabeth Muller, the group’s executive director, says the group is advancing knowledge in three ways. First, they use statistical methods to estimate air pollution levels for unmonitored locations, based on readings from surrounding locations. Second, they’re making historical data readily available for the first time (in convenient formats like the animation below). “The problem is, you can find out what pollution is right now, this hour, at most of the stations across China,” she tells Spectrum. “But you can’t find out what it was yesterday, or a week ago, or a year ago.” 

Third, the group is meshing local pollution measurements with wind measurements to reveal the sources of pollution (i.e., what’s blowing in the wind, and from where). “We’re hopeful that these maps will help both the government and the public at large to appreciate the importance of this issue,” Muller says. “And because we’re able to identify sources, that should make it easier to do something about it.” 

Muller says she thinks there’s a faction of the Chinese government that wants to openly address the problem of air pollution, but another faction that fears such a frank discussion will endanger “social harmony.” Which indeed it might. When people learn that breathing the air can kill them—Berkeley Earth estimates that air pollution contributes to 1.6 million deaths each year—they’re liable to be a little upset. 

The Conversation (0)
This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

Hundreds of charging stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

The number of charging stations in Utrecht has risen sharply over the past decade.

“People are buying more and more electric cars,” says Eerenberg, the alderman. City officials noticed a surge in such purchases in recent years, only to hear complaints from Utrechters that they then had to go through a long application process to have a charger installed where they could use it. Eerenberg, a computer scientist by training, is still working to unwind these knots. He realizes that the city has to go faster if it is to meet the Dutch government’s mandate for all new cars to be zero-emission in eight years.

The amount of energy being used to charge EVs in Utrecht has skyrocketed in recent years.

Although similar mandates to put more zero-emission vehicles on the road in New York and California failed in the past, the pressure for vehicle electrification is higher now. And Utrecht city officials want to get ahead of demand for greener transportation solutions. This is a city that just built a central underground parking garage for 12,500 bicycles and spent years digging up a freeway that ran through the center of town, replacing it with a canal in the name of clean air and healthy urban living.

A driving force in shaping these changes is Matthijs Kok, the city’s energy-transition manager. He took me on a tour—by bicycle, naturally—of Utrecht’s new green infrastructure, pointing to some recent additions, like a stationary battery designed to store solar energy from the many panels slated for installation at a local public housing development.

This map of Utrecht shows the city’s EV-charging infrastructure. Orange dots are the locations of existing charging stations; red dots denote charging stations under development. Green dots are possible sites for future charging stations.

“This is why we all do it,” Kok says, stepping away from his propped-up bike and pointing to a brick shed that houses a 400-kilowatt transformer. These transformers are the final link in the chain that runs from the power-generating plant to high-tension wires to medium-voltage substations to low-voltage transformers to people’s kitchens.

There are thousands of these transformers in a typical city. But if too many electric cars in one area need charging, transformers like this can easily become overloaded. Bidirectional charging promises to ease such problems.

Kok works with others in city government to compile data and create maps, dividing the city into neighborhoods. Each one is annotated with data on population, types of households, vehicles, and other data. Together with a contracted data-science group, and with input from ordinary citizens, they developed a policy-driven algorithm to help pick the best locations for new charging stations. The city also included incentives for deploying bidirectional chargers in its 10-year contracts with vehicle charge-station operators. So, in these chargers went.

Experts expect bidirectional charging to work particularly well for vehicles that are part of a fleet whose movements are predictable. In such cases, an operator can readily program when to charge and discharge a car’s battery.

We Drive Solar earns credit by sending battery power from its fleet to the local grid during times of peak demand and charges the cars’ batteries back up during off-peak hours. If it does that well, drivers don’t lose any range they might need when they pick up their cars. And these daily energy trades help to keep prices down for subscribers.

Encouraging car-sharing schemes like We Drive Solar appeals to Utrecht officials because of the struggle with parking—a chronic ailment common to most growing cities. A huge construction site near the Utrecht city center will soon add 10,000 new apartments. Additional housing is welcome, but 10,000 additional cars would not be. Planners want the ratio to be more like one car for every 10 households—and the amount of dedicated public parking in the new neighborhoods will reflect that goal.

This photograph shows four parked vehicles, each with the words \u201cWe Drive Solar\u201d prominently displayed, and each plugged into a charge point.Some of the cars available from We Drive Solar, including these Hyundai Ioniq 5s, are capable of bidirectional charging.We Drive Solar

Projections for the large-scale electrification of transportation in Europe are daunting. According to a Eurelectric/Deloitte report, there could be 50 million to 70 million electric vehicles in Europe by 2030, requiring several million new charging points, bidirectional or otherwise. Power-distribution grids will need hundreds of billions of euros in investment to support these new stations.

The morning before Eerenberg sat down with me at city hall to explain Utrecht’s charge-station planning algorithm, war broke out in Ukraine. Energy prices now strain many households to the breaking point. Gasoline has reached $6 a gallon (if not more) in some places in the United States. In Germany in mid-June, the driver of a modest VW Golf had to pay about €100 (more than $100) to fill the tank. In the U.K., utility bills shot up on average by more than 50 percent on the first of April.

The war upended energy policies across the European continent and around the world, focusing people’s attention on energy independence and security, and reinforcing policies already in motion, such as the creation of emission-free zones in city centers and the replacement of conventional cars with electric ones. How best to bring about the needed changes is often unclear, but modeling can help.

Nico Brinkel, who is working on his doctorate in Wilfried van Sark’s photovoltaics-integration lab at Utrecht University, focuses his models at the local level. In his calculations, he figures that, in and around Utrecht, low-voltage grid reinforcements cost about €17,000 per transformer and about €100,000 per kilometer of replacement cable. “If we are moving to a fully electrical system, if we’re adding a lot of wind energy, a lot of solar, a lot of heat pumps, a lot of electric vehicles…,” his voice trails off. “Our grid was not designed for this.”

But the electrical infrastructure will have to keep up. One of Brinkel’s studies suggests that if a good fraction of the EV chargers are bidirectional, such costs could be spread out in a more manageable way. “Ideally, I think it would be best if all of the new chargers were bidirectional,” he says. “The extra costs are not that high.”

Berg doesn’t need convincing. He has been thinking about what bidirectional charging offers the whole of the Netherlands. He figures that 1.5 million EVs with bidirectional capabilities—in a country of 8 million cars—would balance the national grid. “You could do anything with renewable energy then,” he says.

Seeing that his country is starting with just hundreds of cars capable of bidirectional charging, 1.5 million is a big number. But one day, the Dutch might actually get there.

This article appears in the August 2022 print issue as “A Road Test for Vehicle-to-Grid Tech.”

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