on December 14, 2015
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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.
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