NASA Studies How COVID-19 Shutdowns Affect Emissions

Deviation from modeled normal nitrogen dioxide levels after COVID-19 lockdowns Using computer models to generate a COVID-free 2020 for comparison, NASA researchers found that since February, pandemic restrictions have reduced global nitrogen dioxide concentrations by nearly 20%. The model simulation and machine learning analysis took place at the NASA Center for Climate Simulation. Its “business as usual” scenario showed an alternate reality version of 2020—one that did not experience any unexpected changes in human behavior brought on by the pandemic.From there it is simple subtraction. The difference between the model simulated values and the measured ground observations represents the change in emissions due to the pandemic response. The researchers received data from 46 countries—a total of 5,756 observation sites on the ground—relaying hourly atmospheric composition measurements in near-real time. On a city-level, 50 of the 61 analyzed cities show nitrogen dioxide reductions between 20-50%.Wuhan, China was the first municipality reporting an outbreak of COVID-19. It was also the first to show reduced nitrogen dioxide emissions—60% lower than simulated values expected. A 60% decrease in Milan and a 45% decrease in New York followed shortly, as their local restrictions went into effect.This visualization presents the deviation from the model as colored hemispheres at each observation site. Whether a site is under lockdown is denoted by a smaller dot at each site, colored grey to denote "no lockdown," and green to denote "under lockdown." Additionally, the deviation for each of three cities, Wuhan, Madrid, and New York is presented as a scrolling line graph at the top of the visualization. Related pages

This 3D volumetric visualization shows the emission and transport of atmospheric methane around the globe between December 9, 2017 and December 1, 2018.Music: "Motion Blur" by Sam Dobson [PRS]Complete transcript available.This video is also available on our YouTube channel. The same 3D volumetric visualization of the emission and transport of atmospheric methane around the globe between December 9, 2017 and December 1, 2018 with only music. This version has no narration.Music: "Motion Blur" by Sam Dobson [PRS]Coming soon to our YouTube channel. This layer of the visualization includes the Earth with the global atmospheric methane emission and transport. The overlay with the date and colorbar is not included. This layer includes only the date and colorbar with transparency. Methane is a powerful greenhouse gas that traps heat 28 times more effectively than carbon dioxide over a 100-year timescale. Concentrations of methane have increased by more than 150% since industrial activities and intensive agriculture began. After carbon dioxide, methane is responsible for about 23% of climate change in the twentieth century. Methane is produced under conditions where little to no oxygen is available. About 30% of methane emissions are produced by wetlands, including ponds, lakes and rivers. Another 20% is produced by agriculture, due to a combination of livestock, waste management and rice cultivation. Activities related to oil, gas, and coal extraction release an additional 30%. The remainder of methane emissions come from minor sources such as wildfire, biomass burning, permafrost, termites, dams, and the ocean. Scientists around the world are working to better understand the budget of methane with the ultimate goals of reducing greenhouse gas emissions and improving prediction of environmental change. For additional information, see the Global Methane Budget.The NASA SVS visualization presented here shows the complex patterns of methane emissions produced around the globe and throughout the year from the different sources described above. The visualization was created using output from the Global Modeling and Assimilation Office, GMAO, GEOS modeling system, developed and maintained by scientists at NASA. Wetland emissions were estimated by the LPJ-wsl model, which simulates the temperature and moisture dependent methane emission processes using a variety of satellite data to determine what parts of the globe are covered by wetlands. Other methane emission sources come from inventories of human activity. The height of Earth’s atmosphere and topography have been vertically exaggerated and appear approximately 50-times higher than normal in order to show the complexity of the atmospheric flow. As the visualization progresses, outflow from different source regions is highlighted. For example, high methane concentrations over South America are driven by wetland emissions while over Asia, emissions reflect a mix of agricultural and industrial activities. Emissions are transported through the atmosphere as weather systems move and mix methane around the globe. In the atmosphere, methane is eventually removed by reactive gases that convert it to carbon dioxide. Understanding the three-dimensional distribution of methane is important for NASA scientists planning observations that sample the atmosphere in very different ways. Satellites like GeoCarb, a planned geostationary mission to observe both carbon dioxide and methane, look down from space and will estimate the total number of methane molecules in a column of air. Aircraft, like those launched during NASA’s Arctic Boreal Vulnerability Experiment (ABOVE) sample the atmosphere along very specific flight lines, providing additional details about the processes controlling methane emissions at high latitudes. Atmospheric models help place these different types of measurements in context so that scientists can refine estimates of sources and sinks, understand the processes controlling them and reduce uncertainty in future projections of carbon-climate feedbacks. Related pages

This short visualization shows the orbit of NOAA-20 along with Suomi NPP. The camera rotates to a view perpendicular to the orbit plan, showing the half-orbit separation between the two satellites. This short visualization shows the orbit of NOAA-20 along with Suomi NPP. The camera rotates to a view perpendicular to the orbit plan, showing the half-orbit separation between the two satellites. The Joint Polar Satellite System (JPSS) is the nation’s advanced series of polar-orbiting environmental satellites. JPSS satellites circle the Earth from pole-to-pole and cross the equator 14 times daily in the afternoon orbit—providing full global coverage twice a day. Polar satellites are considered the backbone of the global observing system.The operational JPSS constellation currently consists of the NASA-NOAA Suomi National Polar-Orbiting Partnership satellite, the technology pathfinder mission for JPSS launched in 2011, and NOAA-20, previously called JPSS-1 and launched in 2017. The next satellite in the series, JPSS-2, is scheduled to launch in the first quarter of 2022. Once it is accepted into the constellation post-launch, JPSS-2 will be renamed NOAA-21 and replace Suomi-NPP. JPSS represents significant technological and scientific advancements in observations used for severe weather prediction and environmental monitoring. These data are critical to the timeliness and accuracy of forecasts three to seven days in advance of a severe weather event. JPSS is a collaborative effort between NOAA and NASA. Related pages

Preventative measures adopted to reduce the rate of spread of COVID-19 in the U.S. prompted an overall slowdown in economic activity and fewer vehicles on the roadways in the spring of 2020. To examine changes in air quality in California, NASA constructed weekly averaged nitrogen dioxide (NO2) maps for March and April 2020 at 0.05° grid spacing from high-quality, cloud-free retrievals provided by Tropospheric Monitoring Instrument (TROPOMI) level 2 data.During first weekday period (March 2-6, pre-shutdown) when COVID-19 measures were yet to be implemented, the largest tropospheric NO2 concentrations were observed in Los Angeles and bordering counties with a less prominent peak in NO2 around San Francisco. The TROPOMI scans also resolved areas of enhanced NO2 along the heavily trafficked corridor of State Route 99 (SR-99) in the Central Valley. As initial, soft COVID-19 measures were adopted by businesses in California during the second weekday period, March 9-13, TROPOMI observed strong reductions in tropospheric column NO2 around the large cities of Los Angeles and San Francisco along with noticeable decreases along SR-99. When California announced statewide “shelter-in-place” orders during the third weekday period, March 16-20, further decreases in NO2 were apparent throughout all populated areas in the state and along SR-99. Further weekly areages showed variable decreases in NO2 as decreased economic activity continued. Overall, these observed reductions in TROPOMI NO2 throughout the spring season are the result of decreased emissions on top of the seasonal changes in meteorological conditions. TROPOMI Nitrogen Dioxide animation. TROPOMI Nitrogen Dioxide still For More InformationSee [https://nasasport.wordpress.com/2020/04/04/new-generation-satellite-observations-monitor-air-pollution-during-covid-19-lockdown-measures-in-california/](https://nasasport.wordpress.com/2020/04/04/new-generation-satellite-observations-monitor-air-pollution-during-covid-19-lockdown-measures-in-california/) Related pages

Tropospheric NO2 Column, Animated GIF Tropospheric NO2 Column, March 2015-2019 Average, Northeast USA, With Labels Tropospheric NO2 Column, March 2020, Northeast USA, With Labels Tropospheric NO2 Column, March 2015-2019 Average, Northeast USA, No Labels Tropospheric NO2 Column, March 2020, Northeast USA, No Labels Tropospheric NO2 Column Animation, With Total Mass Inset Colorbar, Quantitative Colorbar, Qualitative Animated Gif -tropospheric NO2 from March 15-April 15 time series in southeastern US. Tropospheric NO2 Column, March 15-April 15 2015-2019 Average, Southeast USA, With Cities Tropospheric NO2 Column, March 15-April 15 2020 Average, Southeast USA, With Cities Tropospheric NO2 Column, March 15-April 15 2015-2019 Average, Southeast USA, No Cities Tropospheric NO2 Column, March 15-April 15 2020 Average, Southeast USA, No Cities Tropospheric NO2 Column, March 15-April 15 2015-2019 Average, Southeast USA, No Labels Tropospheric NO2 Column, March 15-April 15 2020 Average, Southeast USA, No Labels Animated Gif -tropospheric NO2 from March 15-April 15 time series in the state of Florida Tropospheric NO2 Column, March 15-April 15 2015-2019 Average, Florida, With Cities Tropospheric NO2 Column, March 15-April 15 2020 Average, Florida, With Cities Tropospheric NO2 Column, March 15-April 15 2015-2019 Average, Florida, No Cities Tropospheric NO2 Column, March 15-April 15 2020 Average, Florida, No Cities Tropospheric NO2 Column, March 15-April 15 2015-2019 Average, Florida, No Labels Tropospheric NO2 Column, March 15-April 15 2020 Average, Florida, No Labels Colorbar, Range 0-5 x10^15 molecules/cm^2 Animated Gif of tropospheric NO2, March 25 -April 25 of Indian subcontinent.On March 24, 2020, Prime Minister Modi ordered a nationwide stay-at-home order for India’s 1.3 billion citizens in an attempt to slow the spread of COVID-19. Tropospheric NO2 Column, March 25-April 25 2017-2019 Average, Indian Subcontinent, With Labels Tropospheric NO2 Column, March 25-April 25 2020 Average, Indian Subcontinent, With Labels Tropospheric NO2 Column, March 25-April 25 2017-2019 Average, Indian Subcontinent, No Labels Tropospheric NO2 Column, March 25-April 25 2020 Average, Indian Subcontinent, No Labels Animated Gif - Tropospheric SO2 Column, March 25-April 25 time series of Indian Subcontinent. On March 24, 2020, Prime Minister Modi ordered a nationwide stay-at-home order for India’s 1.3 billion citizens in an attempt to slow the spread of COVID-19. Tropospheric SO2 Column, March 25-April 25 2017-2019 Average, Indian Subcontinent, With Labels Tropospheric SO2 Column, March 25-April 25 2020 Average, Indian Subcontinent, With Labels. On March 24, 2020, Prime Minister Modi ordered a nationwide stay-at-home order for India’s 1.3 billion citizens in an attempt to slow the spread of COVID-19. As a consequence, less fossil fuels are being consumed and, subsequently, there is less air pollution in India and in neighboring countries, including Pakistan, Nepal, Bangladesh, and Sri Lanka. Colorbar, Range 0-1 Dobson Units Animated Gif -tropospheric NO2 from March 25-April 25 time series in southwestern US. Tropospheric NO2 Column, March 25-April 25 2015-2019 Average, Southwest USA, With Labels Tropospheric NO2 Column, March 25-April 25 2020 Average, Southwest USA, With Labels Tropospheric NO2 Column, March 25-April 25 2015-2019 Average, Southwest USA, No Labels Tropospheric NO2 Column, March 25-April 25 2020 Average, Southwest USA, No Labels Colorbar, Range 0-12 x10^15 molecules/cm^2 Over the past several weeks, the United States has seen significant reductions in air pollution over its major metropolitan areas. Similar reductions in air pollution have been observed in other regions of the world. These recent improvements in air quality have come at a high cost, as communities grapple with widespread lockdowns and shelter-in-place orders as a result of the spread of COVID-19. One air pollutant, nitrogen dioxide (NO2), is primarily emitted from burning fossil fuels (diesel, gasoline, coal), coming out of our tailpipes when driving cars and smokestacks when generating electricity. Therefore, changes in NO2 levels can be used as an indicator of changes in human activity. However, care must be taken when processing and interpreting satellite NO2 data as the quantity observed by the satellite is not exactly the same as the NO2 abundance at ground level. NO2 levels are influenced by dynamical and chemical processes in the atmosphere. For instance, atmospheric NO2 levels can vary day-to-day due to changes in the weather, which influences both the lifetime of NO2 molecules as well as the dispersal of the molecules by the wind. It is also important to note that satellites that observe NO2 cannot see through clouds, so all data shown is for days with low amounts of cloudiness. If processed and interpreted carefully, NO2 levels observed from space serve as an effective proxy for NO2 levels at Earth's surface.NASA's air quality group is also monitoring other air pollutants, such as sulfur dioxide (SO2). Major anthropogenic activities that emit SO2 include electricity generation, oil and gas extraction, and metal smelting. SO2 is emitted during electricity generation if the coal burned has sulfur impurities that are not removed (or not “scrubbed”) from the plant’s exhaust stacks.For more information on what pollutants NASA satellites observe, visit the NASA Air Quality website. Related pages

GEOS-5 Modeled Cloud Cover, With LabelsThis video is also available on our YouTube channel. GEOS-5 Modeled Cloud Cover, No Labels This visualization shows cloud cover as modeled by the GEOS-5 atmospheric model, using observations as its input, over the course of three days. The time period repeats halfway through the animation.This visualization was created in part to support Earth Day 2020 media releases. Related pages

Animation of global aerosols from August 1, 2019 to January 29, 2020 Time series starting in Dec 2019 and going through Jan 2020. Color tables for the different aerosols visualized. This visualization shows the global distribution of aerosols, generated by NASA’s GEOS-FP data assimilation system, from August 1, 2019 to January 14,2020—capturing the aerosols released by the extreme bushfires in Australia in December 2019 and January 2020 and how they are transported around the globe over the South Pacific Ocean.Different aerosol species are highlighted by color, including dust (orange), sea-salt (blue), nitrates (pink), sulfates (green), and carbon (red), with brighter regions corresponding to higher aerosol amounts. NASA's MODIS observations constrain regions with biomass burning as well as the aerosol optical depths in GEOS, capturing the prominent bushfires in Australia and transport of emitted aerosols well downstream over the South Pacific Ocean. Weather events including Hurricane Dorian in August – September 2019 and other tropical cyclones around the world, along with major fire events in South America and Indonesia in August - September 2019 are also shown.The local impacts of the Australian bushfires have been devastating to property and life in Australia while producing extreme air quality impacts throughout the region. As smoke from the massive fires has interacted with the global weather, the transport of smoke plumes around the global have accelerated through deep vertical transport into the upper troposphere and even the lowermost stratosphere, leading to long-range transport around the globe. For More InformationSee [https://gmao.gsfc.nasa.gov/research/science_snapshots/2020/Australia_fires_smoke.php](https://gmao.gsfc.nasa.gov/research/science_snapshots/2020/Australia_fires_smoke.php) Related pages

Earth’s atmosphere is mainly comprised of nitrogen and oxygen but also contains traces of hundreds of chemical compounds. While tiny in abundance, these chemicals have an outsized impact on humans and the environment due to their reactivity and toxicity. This visualization shows a computer simulation of the complexity of the chemical system of the atmosphere produced by NASA's GEOS modeling system with atmospheric chemistry. Shown is a sequence of modeled surface concentrations of 96 chemical species during the time period July 22, 2018 to October 2, 2018. These chemicals undergo rapid changes as they are being emitted by natural and anthropogenic activities, transported by prevailing winds and vertical lifting motions, deposited to the surface, or chemically transformed.The visualization starts with a global map of model predicted concentrations of surface ozone, a potent air pollutant that is chemically produced from hydrocarbons and nitrogen oxides under the presence of sunlight. Consequently, the highest concentrations of surface ozone can be found during daytime close to urban areas and in the vicinity of forest fires (e.g., Africa). At night, ozone is chemically destroyed in highly polluted environments, leading to very low nighttime concentrations over industrial areas such as Eastern China. These processes are captured in detail by NASA’s GEOS composition forecast (CF) system, which incorporates the latest scientific understanding of the physics and chemistry that guide the formation of ozone, along with measurements from satellites and other instrument platforms. A particular feature of the model system used here is its comprehensive representation of atmospheric chemistry using the GEOS-Chem chemistry model, capturing 240 gaseous species that react with each other via 725 chemical reactions. Directly or indirectly, all of these species impact the formation of ozone. The visualization shows snapshots of modeled concentrations of 96 of the most important chemical compounds, loosely grouped into seven ‘families’ based on their physical and chemical properties. Very tightly linked to ozone is the hydrogen oxides “HOx” family. It contains the highly reactive hydroxyl radical, OH, which plays a prominent role in atmospheric chemistry due to its role as a ‘cleansing agent’ of the atmosphere. The abundance of OH, which is subject to the availability of water vapor and sunlight, in turn directly impacts the atmospheric lifetime of hydrocarbons such as methane and carbon monoxide. Human activities constitute an important source for both of these gases (beside natural sources) and directly influence the long-term concentration trends of these pollutants, as can be directly observed from NASA satellites. Another related group of chemicals are hydrocarbons from biogenic activity: “Isoprene oxidation”. Plants emit hundreds of (structurally similar) compounds, with isoprene being the most important one. These compounds rapidly react with each other through a complex cascade of reactions, which makes the chemistry over vegetation-rich areas such as rain forests or the Southeast US challenging to simulate. Biogenic compounds also play an important role for the formation of aerosols: tiny particles that can constitute a major health risk when inhaled. The abundance and composition of aerosol particles is highly variable and is influenced by anthropogenic activities (e.g., soot from biofuel burning) as well as natural events, such as wildfires, dust storms, volcanic eruptions, and sea spray. The ocean is also a source of another group of chemicals, the halogens. These species tend to be highly reactive and can effectively destroy ozone, especially over remote areas. The last chemical group depicted in the visualization is related to nitrogen. Nitrogen oxides are central to atmospheric chemistry in general and ozone formation in particular. At the surface, the most important source of nitrogen dioxide (NO2) is the combustion of fossil fuels. As a result, NO2 concentrations are highest over urban areas (e.g. highways, power plants) and along ship routes.The visualization ends back at the beginning with ozone, illustrating the connectiveness of the chemical system of the atmosphere. Given the complexity of atmospheric chemistry, computer simulations – such as those by the NASA GEOS composition forecasting system – are an essential tool to understanding the formation of air pollution and to help formulate effective mitigation strategies.Here's a list of each of the chemical species shown and their groupings (ppbV=pars per billion by volume): 96 chemical species are shown from a GEOS atmospheric simulation Color bars Related pages

Global surface ozone from a GEOS model run Color bar for ozone (range is 0 to 100 parts per billion). Black and darker blues are lower and lighter blues and white are higher. Ozone (O3) is a highly reactive gas that is photochemically produced in the atmosphere. In the stratosphere, it absorbs ultraviolet radiation and protects life on Earth. Close to the surface, however, ozone is a potent pollutant that is harmful to both humans and the environment. This animation shows the amount (concentration) of ozone in the atmosphere at the surface of Earth, as represented by the GEOS composition forecast system (GEOS-CF) for the time period July 22 – August 10 2018. High concentrations of ozone are depicted in white while low concentrations are shown in dark blue. As shown in the simulation, surface ozone exhibits a strong change through the day (diurnal cycle). It is formed in the daytime, under the influence of sunlight, through chemical reactions of nitrogen oxides and volatile organic compounds. The highest concentrations are found in the afternoon in the vicinity of urban areas, a consequence of human activities releasing nitrogen oxides and other pollutants, and in other polluted regions, such as around wildfires. Related pages

Major sources of tropospheric NO2 include industrial emissions, automobile traffic, forest and brush fires, microbiological soil emissions, lightning, and aircraft. More than half of the total NO2 emissions are estimated to be anthropogenic, mainly from the burning of fossil fuels for energy production, transportation, and industrial activities. NO2 has a relatively short lifetime (about a day) and is therefore concentrated near its sources. Animation of global map of OMI Troposheric NO2 ffrom July 1, 2017 to June 30, 2018. Related pages

This video provides an overview of the study findings. An HD version of this video is available here: Human Fingerprint on Global Air Quality This global map shows the concentration of nitrogen dioxide in the atmosphere as detected by the Ozone Monitoring Instrument aboard the Aura satellite, averaged over 2005. This global map shows the concentration of nitrogen dioxide in the troposphere as detected by the Ozone Monitoring Instrument aboard the Aura satellite, averaged over 2014. Color bar for absolute nitrogen dioxide concentrations global images. Nitrogen dioxide concentrations across the United States, averaged over 2005. Nitrogen dioxide concentrations across the United States, averaged over 2014. Color bar for absolute nitrogen dioxide concentrations across the United Sates. The trend map of the United States shows the large decreases in nitrogen dioxide concentrations from 2005 to 2014. Only decreases are highlighted in this map. Color bar for the trend in nitrogen dioxide concentrations changes across the United Sates. The trend map of Europe shows the change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide concentrations changes across Europe. The trend map of East Asia shows the change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide concentrations changes across East Asia. The trend map of the Middle East shows the change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide concentrations changes across the Middle East. The trend map of the Persian Gulf shows the change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide concentrations changes across the Persian Gulf. Nitrogen dioxide concentrations in South Africa, averaged over 2014. Color bar for absolute nitrogen dioxide concentrations across in South Africa. The trend map of South Africa shows the change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide concentrations changes in South Africa. The trend map for North Dakota shows the percent change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide percent changes in North Dakota. The trend map for Texas shows the percent change in nitrogen dioxide concentrations from 2005 to 2014. Color bar for the trend in nitrogen dioxide percent changes in North Dakota. Globe background layer Europe background layer East asia background layer Middle east background layer Persian gulf background layer S Africa background layer N Dakota background layer Texas background layer Using new, high-resolution global satellite maps of air quality indicators, NASA scientists tracked air pollution trends over the last decade in various regions and 195 cities around the globe. According to recent NASA research findings, the United States, Europe and Japan have improved air quality thanks to emission control regulations, while China, India and the Middle East, with their fast-growing economies and expanding industry, have seen more air pollution. Scientists examined observations made from 2005 to 2014 by the Ozone Monitoring Instrument aboard NASA's Aura satellite. One of the atmospheric gases the instrument detects is nitrogen dioxide, a yellow-brown gas that is a common emission from cars, power plants and industrial activity. Nitrogen dioxide can quickly transform into ground-level ozone, a major respiratory pollutant in urban smog. Nitrogen dioxide hotspots, used as an indicator of general air quality, occur over most major cities in developed and developing nations.The following visualizations include two types of data. The absolute concentrations show the concentration of tropospheric nitrogen dioxide, with blue and green colors denoting lower concentrations and orange and red areas indicating higher concentrations. The second type of data is the trend data from 2005 to 2014, which shows the observed change in concentration over the ten-year period. Blue indicated an observed decrease in nitrogen dioxide, and orange indicates an observed increase. Please note that the range on the color bars (text is in white) changes from location to location in order to highlight features seen in the different geographic regions. Related pages