WHO: Millions Dying of Urban Air Pollution

GENEVA, Switzerland, September 30, 2011 (ENS) – “Across the world, city air is often thick with exhaust fumes, factory smoke or soot from coal burning power plants,” says Dr. Maria Neira of the World Health Organization. “In many countries there are no air quality regulations and, where they do exist, national standards and their enforcement vary markedly.”

As WHO Director for Public Health and Environment, Dr. Neira wants to draw public awareness to a new and unprecedented set of air quality data compiled by the World Health Organization from 1,081 cities in 91 countries, including capital cities and cities with more than 100,000 residents.

WHO estimates more than two million people die every year from breathing in tiny particles present in indoor and outdoor air pollution.

PM10 particles, measuring 10 micrometers or less, are an important indicator of urban air pollution and the health risks associated with the complex mixtures of pollutants typically found in cities.

Air pollution in Cairo, Egypt showing pyramids enveloped in smog, April 2008 (Photo by Nina Hale)

The smaller PM10 particles are able to penetrate deep into the lungs, and also to cross into the blood, causing damage in many organ systems. Exposure to these particles can cause heart disease, lung cancer, asthma, and acute lower respiratory infections.

“Air pollution is a major environmental health issue and it is vital that we increase efforts to reduce the health burden it creates,” said Dr. Neira. “If we monitor and manage the environment properly we can significantly reduce the number of people suffering from respiratory and heart disease, and lung cancer.”

The WHO air quality guidelines for PM10 particles is 20 micrograms per cubic metre (µg/m3) as an annual average, but the new data shows that average PM10 in some cities has reached up to 300 µg/m3.

The great majority of urban populations have an average annual exposure to PM10 particles in excess of the WHO Air Quality guidelines. Only a few cities currently meet the guideline values, the data show.

Cities in the Eastern Mediterranean region have the most polluted air, according to WHO’s compilation of data, while cities in the Americas and Europe have the cleanest air.

For 2008, the estimated mortality attributable to outdoor air pollution in cities amounts to 1.34 million premature deaths. If the WHO guidelines had been universally met, an estimated 1.09 million deaths could have been prevented in 2008.

Air pollution in New Delhi, India, January 2011 (Photo by Jean-Etienne Minh-Duy Poirier)

The number of deaths attributable to urban air pollution has increased from the previous estimation of 1.15 million deaths in 2004.

The increase in the mortality estimated to be attributable to urban air pollution is linked to recent increases in air pollution concentrations and in urban population size, as well as improved data availability and methods employed.

WHO is calling for greater awareness of health risks caused by urban air pollution, implementation of effective policies and close monitoring of the situation in cities.

A reduction from an average of 70 µg/m3 of PM10 to an annual average of 20 µg/m3 of PM10 is expected to yield a 15 percent reduction in mortality – considered a major public health gain.

At higher levels of pollution, similar reductions would have less impact on reducing mortality, but would still bring important health benefits.

“Solutions to outdoor air pollution problems in a city will differ depending on the relative contribution of pollution sources, its stage of development, as well as its local geography,” said Dr. Carlos Dora, WHO Coordinator for Interventions for Health Environments in the Department of Public Health and Environment.

“The most powerful way that the information from the WHO database can be used is for a city to monitor its own trends in air pollution over time, so as to identify, improve and scale-up effective interventions,” said Dr. Dora.

Air pollution at sunset over Kuwait City, December 2009 (Photo by ShaDn)

In developed as well as developing countries, the largest contributors to urban outdoor air pollution include motor transport, small-scale manufacturers and other industries, burning of biomass and coal for cooking and heating, as well as coal-fired power plants.

Residential wood and coal burning for space heating is an important contributor to air pollution, especially in rural areas during colder months.

“Local actions, national policies and international agreements are all needed to curb pollution and reduce its widespread health effects,” said Dr. Michal Krzyzanowski, head of the WHO European Centre for Environment and Health in Bonn, Germany.

He said the new data identify regions where action is most needed and allows assessment of the effectiveness of implemented policies and actions.

The air quality data comes from publicly available results of air quality monitoring conducted by individual cities. WHO says the measurements used in the database are taken from monitoring sites in cities, including roadsides. In order to avoid overestimates, the measures were not taken at industrial and other recognized “hot spots” that are not representative of the exposure of many people.

Measurements as applied in the database, including reported PM10 levels, represent annual averages. In some cities, measurements of even smaller particles such PM2.5 are available, and these are also included in the database.

The data are based on measurements from 2003 to 2010, with the great majority being reported for the period 2008 – 2009. Data are presented for individual cities, urban populations of countries, and for WHO regions.

Click here to see these air quality data sets, along with the latest updates of the related burden of disease, and frequently asked questions.

Copyright Environment News Service (ENS) 2011. All rights reserved.