The covid-19 pandemic has changed the world, ceasing growing geographical areas and portions of the economy in an effort to slow the spread of the virus.
The impacts were deep in the ground, but government-mandated crashes also brought back the atmosphere. Satellite data from China, the first fire epicenter, and Italy, the second hot spot, showed large drops in pollution after crashes that limited the movement of people and products and the capabilities of factories to produce things. With the pandemic becoming more and more prevalent in the United States, Americans have already begun to move less as some have and governors have come to similar measures.
In an effort to track the impacts, Earther has put together an interactive map to explain changes in air pollution not just in the United States but around the world. The map is based on Google Earth Engine and uses data collected from the European Space Agency’s Sentinel-5P satellite, which surrounds Earth capturing various types of data. Includes four snapshots from December 2019 through March 20, 2020. Sentinel satellite data shows nitrogen dioxide, which is a practical proxy for human activity.
“Nitrogen dioxide is produced by the combustion of a fossil fuel and is therefore often used as an urban pollution tracer,” said Barbara Dix, an atmospheric researcher at the University of Cooperative Institute for Environmental Science Research. the Colorado Boulder, Earther said in an email. “The combustion of fossil fuels directly emits a lot of nitric oxide and a little nitrogen dioxide (often called NOx together), but nitric oxide is quickly converted to nitrogen dioxide in the atmosphere. Nitrogen dioxide can be easily measured by the satellite “.
Given that fossil fuels fuel everything, from cars to electricity, satellite images of nitrogen dioxide really show the impact covid-19 has on society as no other data source has. There are clear signs of the impact of the virus around the world, and we look at some of the US examples below. But it’s also important to note a few small caveats as you scroll down the map and look at the before and after pictures.
The data presented here is a series of one-day snapshots. Climate models can track pollution around and disperse while rain and even sun levels can also change Sentinel-5P readings. There are also natural sources of nitrogen dioxide that can affect readings. The data in Google Earth Engine is not necessarily quality filtered. Dix noted that the cloud media can be packed with lessons, which may be why on the interactive map there are some tougher areas such as northern New England in March or signs of pollution in the Seattle area where it doesn’t. it may not be much. It will take time for researchers to really dive into the data and filter to gain an end-to-end understanding of the impact of covid-19 on air pollution. Despite these drawbacks, trends in many major cities around the United States are stagnant and clearly at least partly related to the changes forced by the covid-19 pandemic.
“The rapid decrease we see in nitrogen dioxide due to covid-19 is unprecedented,” said Dix. “We are witnessing a global experiment where one source of emission is rapidly decreasing (NOx), while other sources are always going to slow or slow down. A lot of atmospheric science will come out of this.”
“I imagine that the air pollution monitoring data collected during covid-19 are useful to test our fundamental knowledge of pollutant sources (economic sectors, natural emissions, etc.), nitrogen dioxide chemistry, ozone and particulate matter, and the health effects and short-term ecosystem of air pollution, “Viral Shah, a postdoctoral researcher at Harvard, told Earther in an email.
California became the first state in the United States to issue a shelter order in effect on March 19, though many cities made their decision to close earlier. The resulting decrease in pollution from January to March in the state’s major metro areas. Los Angeles is a major source of pollution because of its car culture, and the city’s precipitous fall in pollution is clear. Traffic reports back up satellite data. Bay and San Diego also saw contamination disperse in the face of an on-site shelter order.
The impact extends across the border. Tijuana – which is closely linked to San Diego – has seen pollution dissipate to virtually nothing. Ditto for El Paso and Juarez visible further east. The Mexican and US governments have agreed to partially close the border in an effort to halt the spread of covid-19.
Although not in the closed states, Salt Lake City, Phoenix, and Las Vegas have all degree of restrictions on residents and businesses. And once again, the map clearly shows that it is likely to have an impact on pollution.
The Northeast Corridor
The populous area stretching from Boston to Washington, DC, is the epicenter of the US coronavirus outbreak as well as a hub of economic and political activity. It is also an area where states and cities have moved quickly to close non-essential services to slow the spread of the virus.
Even though New Yorkers are not as dependent on the car as their Los Angeles counterparts, there are still so many normal vehicles on NYC roads and dense groups of buildings that emit pollution. Ditto for Boston, Philadelphia, Baltimore and Washington, which normally form a daisy contamination chain along Interstate 95. With the covid-19 blocks, the chain was broken.
The area from Minnesota to West Virginia forms the largest group of states in block order in effect. Six governors have already put their stats on the blockade or will do so shortly.
The data here is a bit more buzz, but some clear trends are apparent. Car-centric Detroit has a big dip in pollution. Sprawling Chicago pollution also disappears.
The US-Canada border, like its southern counterpart, is also closed off on essential services and trade. The province of Ontario is calling for a shutdown at the end of last week, and the impact of these movements is also showing on the map. Contamination is also felt in the neighborhood of Detroit, Windsor, and Toronto further east.
A strange blow is a hot spot of pollution in Kansas near Emporia. That could be one of the ten Dix data artifacts or nitrogen dioxide emissions possibly attached to the fires they create through state practices every spring.
Texas is part of the South
Although the South has been slow as hell for action, the Texas governor’s lieutenant spent Monday actively advocating for leaving the old dead to save shareholder value, the impacts are still noticeable there. While the data is a bit noisy, nitrogen dioxide emissions in Houston, a hot spot for the petrochemical industry, appear to have decreased. New Orleans – another petrochemical hot spot that is located the only southern state to call for a total blockade – seems to have seen a drop in pollution as well.
Which can be linked to the fortunes of fossil fuels, which have been wiped out due to a price war in Saudi Arabia and fueling demand as the world economy slows. Strong dives are also visible in Mexican cities such as Monterrey, which may be linked to the closure of borders. Explore the full map here.
Updated, Wednesday, March 25 11:40 am: This post has been updated to reflect that nitric oxide can be converted to nitrogen dioxide. The latest map label in this post was also updated after a furious editorial discussion if Texas is part of the “South.”