Public health and environment?remained unaffected in China, although low levels of iodine-131, a radioactive material, were detected in the air above Heilongjiang Province for the second day on Sunday, authorities said.

The Ministry of Health has launched a campaign in 14 cities and provinces in northeast?area and coastal area to monitor the level of radioactive material in foods and tap water.

According to China's National Nuclear Emergency Coordination Committee, the level of iodine-131 detected in the air on Sunday has largely remained the same as on?Saturday.

On Saturday, radioactive material was detected in the air in China for the first time. The material was believed to be released from the crippled nuclear power plant in Japan's Fukushima Prefecture.

So far, no protective measures are needed, the authorities reiterated,?because the radioactive material will not affect public health and the environment, according to the monitoring and analysis by a Beijing-based emergency response center under the World Meteorological Organization, the International Atomic Energy Agency, the State Oceanic Administration and the Ministry of Environmental Protection.