Gasping for fresh air

More than 5.5 million people worldwide are dying prematurely every year as a result of air pollution, according to new research. The main culprit is the emission of small particles from power plants, factories, vehicle exhausts and from the burning of coal and wood. Breathing in tiny liquid or solid particles can increase the risk of heart disease, stroke, respiratory complaints and even cancer. Most of these deaths are occurring in the rapidly developing economies of China and India.

According to the study, air pollution causes more deaths than other risk factors like malnutrition, obesity, alcohol and drug abuse, and unsafe sex. The Global Burden of Disease Project puts it as the fourth greatest risk behind high blood pressure, dietary risks and smoking.

"In Beijing or Delhi on a bad air pollution day, the number of fine particles (known as PM2.5) can be higher than 300 micrograms per cubic metre," explained Dan Greenbaum from the Health Effects Institute, in Boston, US. "The number should be about 25 or 35 micrograms."

In China, there are said to be about 1.6 million deaths a year. In China, the dominant factor is particle emissions from coal burning. The project calculates this source alone is responsible for more than 360,000 deaths every year. Even though China has targets to restrict coal combustion and emissions in the future, it may struggle to bring down the number of deaths because it is acquiring an aging population and these citizens are naturally more susceptible to the illnesses associated with poor air quality.

In India, it is roughly 1.3 million deaths. In India, the problem that draws particular attention is the practice of burning wood, dung, crop residues and other materials for cooking and heating. This "indoor pollution" causes far more deaths than "outdoor pollution". Looking at the broad economic trends in India the country runs the risk of having even poorer air quality in the future. Chandra Venkataraman, from the Indian Institute of Technology Bombay, in Mumbai, warned: "Despite proposed emissions control, there is significant growth in the demand for electricity as well as industrial production. So, through to 2050, this growth overshadows the emissions controls (in our projections) and will lead to an increase in future air pollutant emissions in 2050 in India."