Beijing, Tianjin and Hebei hit hardest by pollution

Air pollution, including high ozone levels, is most severe in Beijing, Tianjin and Hebei province, according to a report released by the Environmental Protection Ministry on Wednesday.

Almost 40 percent of the 74 cities with publicized readings for fine particles failed to meet the national standard for three months or more during the first half of 2013, the report said.

The report highlighted air quality in the three key areas and 74 cities from January to June.

Seven cities in Hebei province were in the top 10 for pollution, with Shijiazhuang the hardest-hit. Less than one-in-ten days saw air quality within the national standard.

The average readings for PM2.5 - particulate matter smaller than 2.5 micrometers in diameter that can reach deep into the lungs and bloodstream - for all cities in the Beijing, Tianjin and Hebei area failed to meet the national standard of 35 microgram per cubic meter.

In the Yangtze River Delta area, the national standard for the PM2.5 level was only met in Zhoushan, Zhejiang province. The situation in the Pearl River Delta area was no better, with only Huizhou in Guangdong province meeting the standard.

Ozone poses an even higher threat to human health than PM2.5, and its concentration is usually high in summer.

Readings of ozone levels in the three key areas all exceeded the national level. Ozone replaced PM2.5 to be the top air pollutant in the Pearl River Delta area in June.