NASA has just published the first long-term global map that shows density of particulate matter below 2.5 micrometres in diameter. This size is important, because it’s small enough to get past the body’s defences and accumulate in the lungs, making it dangerous to human health. Epidemologists believe that they cause millions of premature deaths each year.
The map, as you can see above, shows a wide band of very high concentrations of particulate matter across the Sahara, Middle East, Central Asia and China, only interrupted by the Himalayas. Central Europe also shows a spike, including the south-east corner of England, and urban areas in North and South America stand out too.
The World Health Organisation’s recommended level is 10 micrograms per cubic metre, so anything on the map that’s green or above is cause for concern. Once in the lungs, the particles can cause asthma, cardiovascular diseases and bronchitis. Some very fine particles can even get into the bloodstream. Read more here.