WHO finds urban air pollution 'too high'

Air pollution within many of the world's cities is breaching the World Health Organization's (WHO) guidelines for healthy air quality. The organisation found that of the people living in one of 1,600 cities from 91 countries included in a recent survey, around 90 per cent were exposed to air that failed to meet with safe levels of pollutants. 

According to the WHO, around half of the world's population that lives in urban environments is exposed to air that contains pollutants at levels around 2.5 times higher than is recommended. The survey found that the worse city air quality was found in Asia, closely followed by South America and the US.

Safe levels of air quality as set by the WHO, are based upon the concentrations of particulate matter. This form of pollution is highly dangerous in high concentrations as it can be absorbed through the lungs into the rest of the body, causing a number of health issues - including heart attacks, lung cancer and respiratory illnesses.

The WHO currently recommends that particulate matter measuring under 2.5 micrometers (PM2.5) should not be at concentrations above ten micrograms per cubic meter as an annual average. Particulate matter measuring up to ten micrometres (PM10) should not be present at concentrations higher than 20 micrograms per cubic meter.

Despite these guidelines for safe air quality, the Urban Air Quality database revealed that a large number of urban areas were regularly experiencing levels that are classed as unsafe. The high levels of particulate matter within cities are often visible due to the dense smog that affects them - most commonly seen in cities throughout China.

Despite these findings, the WHO has said that it is still lacking data to create a full picture of the state of urban air pollution around the world. Apparently data is still lacking from a number of areas, especially African cities, which are experiencing increasing levels of air pollution.

According to the WHO, the increasing levels of air pollution around the world is the single largest environmental risk, being linked to many instances of deteriorating human health. It has called on cities to do more to limit air pollution and to adopt measures that could ultimately protect human health and reduce the number of premature deaths.