A new online map tracks tropospheric global nitrogen dioxide concentrations—which we’ve seen drop sharply this year as the pandemic shut down economic activity. “This online platform uses data from the Copernicus Sentinel-5P satellite and shows the averaged nitrogen dioxide concentrations across the globe—using a 14-day moving average. Concentrations of short-lived pollutants, such as nitrogen dioxide, are indicators of changes in economic slowdowns and are comparable to changes in emissions. Using a 14 day average eliminates some effects which are caused by short term weather changes and cloud cover. The average gives an overview over the whole time period and therefore reflects trends better than shorter time periods.” [ESA]
The European Space Agency maps the drop in nitrogen dioxide concentrations in the atmosphere in the wake of coronavirus lockdowns in many countries (see above). [GIS Lounge]
Meanwhile, CESBIO researcher Simon Gascoin built a map that compares NO2 concentrations over the last 30 days with the same period in 2019.
Data for these analyses generally come from the Copernicus Programme’s Sentinel-5P satellite. The Copernicus Atmosphere Monitoring Service issued a warning last week about using the data improperly.
Concentrations of NO2 in the atmosphere are highly variable in space and time: they typically vary by one order of magnitude within each day and quite substantially from one day to another because of the variations in emissions (for example the impacts of commuter traffic, weekdays and weekend days) as well as changes in the weather conditions. This is why, even if observations are available on a daily (currently available from satellites) or even hourly (ground-based observations) basis, it is necessary to acquire data for a substantial period of time in order to check that a statistically robust departure from normal conditions has emerged.
Cloud cover is a factor that needs to be taken into account as well.
Previously: Emissions Drop Due to Coronavirus Outbreak.
As you may have seen elsewhere, the coronavirus pandemic is having an impact on air pollution, as countries shut down human and economic activity in an attempt to deal with the outbreak. Take nitrogen dioxide. Tropospheric NO2 density decreased significantly over China between January and February, and the same seems to be happening in northern Italy, which normally has some of the most severe air pollution in Europe. See the ESA’s animation:
Previously: Mapping Nitrogen Dioxide Pollution.
The U.S. National Library of Medicine’s TOXNET, an interactive map that tracked pollution, chemical exposure, toxicology and other data, was shut down last month. The move has been criticized in the context of the Trump administration’s rollback of environmental protections, but the NLM insists that the decision was theirs. The data mapped by TOXNET is available from other sources, but, and this is the point, not as easily or centrally accessible. [The Hill, Newsweek]
Google is using its Street View cars, now equipped with air-quality sensors, to measure air pollution in California on a block-by-block level.
Earlier this year, we shared the first results of this effort with pollution levels throughout the city of Oakland.
We’re just beginning to understand what’s possible with this hyper-local information and today, we’re starting to share some of our findings for the three California regions we’ve mapped: the San Francisco Bay Area, Los Angeles, and California’s Central Valley (the Street View cars drove 100,000 miles, over the course of 4,000 hours to collect this data!) Scientists and air quality specialists can use this information to assist local organizations, governments, and regulators in identifying opportunities to achieve greater air quality improvements and solutions.
President Trump’s budget proposes eliminating the EPA’s Great Lakes Restoration Initiative. That fact is no doubt what’s behind two publications posting maps earlier this month, only a couple of days apart, showing the environmental stresses on the Great Lakes basin.
Canadian Geographic reposted a map from their July/August 2013 issue:
And the Washington Post included the following map in an article on the proposed elimination of two EPA programs (including the aforementioned Great Lakes Restoration Initiative):
By cross-referencing public data on energy consumption with georeferenced tax lot data, Jill Hubley has created an interactive map of New York City’s greenhouse gas emissions by property, colour-coded to show the biggest emitters. More on how she did it, and what the data reveal. [via]