Energy consumption and rising vehicle emissions amid Asia's rapid economic growth are the main driving force behind the region's increasingly acute air pollution, according to air quality group Clean Air Asia.
"What we are worrying is that we are seeing the PM10 concentration (level) is on the rise again," the group's executive director Sophie Punte told a regional conference on air pollution in Hong Kong.
"Seven out of 10 cities in developing Asia are breathing air that is harmful to their health," she told 600 environmentalists and government officials gathered at the "Better Air Quality" conference organised by the group.
PM10 are air particles that are 10 micrometres, or 10 millionths of a metre (0.0004 of an inch), across.
The group says air pollution will rise as the number of vehicles in Asia is expected to exceed one billion by 2035, while its fuel consumption and resulting carbon dioxide emissions will grow by 400 percent compared to its 2005 levels.
A World Health Organisation study in 2008 found 800,000 out of 1.3 million premature deaths each year due to air pollution are in Asia, and experts warn the figure could rise if no urgent action is taken.