Nasa data reveals lowering urban US air pollution

Nasa's Ozone Monitoring Instrument (OMI) has been in orbit on the Aura satellite for ten years now, meaning it has recorded enough data to provide an accurate insight into the state of atmospheric pollution. The information gathered from the OMI has revealed that air pollution over large cities in the US has actually decreased in recent years, suggesting that air quality controls are being effective.

Images from the satellite show that those living in large cities across the US have been breathing ever-lowering amounts of nitrogen dioxide. This form of air pollution is linked to a number of respiratory illnesses and is emitted by industry and road traffic, meaning it can reach high levels in urban areas.

Nitrogen dioxide is monitored by the US Environmental Protection Agency (EPA) along with five other pollutants that are deemed to be common. The EPA sets safe levels for greenhouse gases in order to limit the effect it has on human health. However, nitrogen dioxide can also lead to the formation of other types of pollution, furthering the damage it can cause.

The gas is involved in the creation of ground-level ozone and particulate pollutants, which have been linked to a number of health problems including heart disease and lung cancer. By monitoring nitrogen dioxide levels, scientists are usually able to estimate general air pollution levels.

With this in mind, the data from the OMI has revealed that, although there are now more cars on the roads throughout large US cities, the levels of nitrogen dioxide created by gasoline-powered combustion engines has actually fallen. According to Nasa scientists, this is due to technological improvements, the implementation of stricter air pollution regulations, and economic changes.

Despite this positive news, the EPA estimates that around 142 million people within the US are still living in areas that experience unhealthy levels of air-borne pollutants. The satellite data also reveals that many other areas of the world are still emitting high levels of greenhouse gases.

Bryan Duncan, an atmospheric scientist at Nasa's Goddard Space Flight Center in Maryland, said: "While our air quality has certainly improved over the last few decades, there is still work to do - ozone and particulate matter are still problems."