[ABC News] NASA maps human impact on global air quality, says changes 'not random'

INFOGRAPHIC: Map of global trends in nitrogen dioxide levels. (NASA)

MAP: United States

How have humans impacted on global air quality? Changes in patterns over the last decade "aren't random", NASA says.

Air pollution patterns around the world from 2005 to 2014 have been tracked in a new study, using global satellite maps of air quality indicators to help "quantify energy usage, environmental policy and civil unrest".

NASA looked at levels of nitrogen dioxide — a common emission from cars, power plants and industrial activity that can quickly transform into ground-level ozone, a major respiratory pollutant in urban smog.

When governments step in and say 'we're going to build something here or we're going to regulate this pollutant', you see the impact in the data.

Atmospheric scientist Bryan Duncan

Hotspots of the atmospheric gas, used as an indicator of general air quality, can be found over most major cities.

The research team studied annual trends in nitrogen dioxide levels around the world, comparing satellite records to information about emission controls regulations, national gross domestic product and urban growth.

"These changes in air quality patterns aren't random," atmospheric scientist and study lead Bryan Duncan said.

"When governments step in and say 'we're going to build something here or we're going to regulate this pollutant', you see the impact in the data."

Who was the largest emitter of nitrogen dioxide?

INFOGRAPHIC: Air pollution trends in the US show high levels of emissions but also the most dramatic reductions. (NASA)

The study found the United States and Europe were among the largest emitters of nitrogen dioxide, although both regions also showed the most dramatic reductions.

Nitrogen dioxide decreased by as much as 50 per cent in both regions, largely due to environmental regulations.

How do air quality levels reflect unrest in Syria?

INFOGRAPHIC: Syria has seen decreases in nitrogen dioxide levels (in blue), and neighbouring countries have seen increases due to population displacement. (NASA)

In Syria, nitrogen dioxide levels have decreased as the country's population has been displaced due to civil war.

However, at the same time neighbouring countries have seen an increase in levels of the gas as displaced Syrians have taken refuge there.

What about manufacturing hub China?

INFOGRAPHIC: Three major Chinese metropolitan areas — Beijing, Shanghai, and the Pearl River Delta (in blue) have seen dramatic decreases in nitrogen dioxide. (NASA)

China saw an increase of 20 to 50 per cent in nitrogen dioxide across most of the country due to the rising use of coal for power.

However, three major metropolitan areas — Beijing, Shanghai, and the Pearl River Delta — saw nitrogen dioxide decreases of as much as 40 per cent.

How does Australia fare?

Nearly all capital cities in Australia saw decreases of between 17.5 to 37.5 per cent in nitrogen dioxide levels, with Melbourne recording the most dramatic change due to environmental regulations.

However, Darwin saw an increase of about 8 per cent in levels.

YOUTUBE: NASA air pollution study

Topics: air-pollution, pollution, environment, united-states, china, syrian-arab-republic

First posted yesterday at 8:15pm