The Beijing Environmental Protection Bureau (EPB) said Wednesday it will improve the urban environment by cutting 2 percent of the four major pollutants in 2013. The four pollutants are sulfur dioxide, nitric oxide, chemical oxygen demand (COD) and ammonium nitrate, the same pollutants the government pledged to cut last year. The EPB will undertake a series of measures to ensure it lives up to its promise, it said Tuesday.

Environmental experts have said that cutting these four pollutants is far from enough to improve the current environment.

Zheng Zaihong, deputy director of the EPB's Pollution Prevention and Control Office, said the reason they chose to focus on the four pollutants is because they are the most widespread in the city.

"Sulfur dioxide and nitric oxide are the two main industrial pollutants from factories, and power plants are the major source of the pollutant," Zheng said. The EPB will ask power and concrete plants to install nitric oxide scrubbers in smokestacks. 

Zheng noted that the most difficult pollutants to control are COD and ammonium nitrate, two elements that affect water quality and are caused by people's everyday lives.

In order to alleviate the problem, a new water treatment plant is to be established in Daxing district this year.

Ma Jun, director with the Institute of Public and Environmental Affairs, said building a treatment plant in Daxing district might not be the ideal way to tackle the pollutants citywide.

"It's better to establish more small water treatment plants, instead of letting pollutants flow over a wider area, contaminating more places," he said.

Qiu Qihong, an engineer from the Beijing Environmental Monitoring Center, said that despite the fact that Beijing has changed to natural gas instead of coal as its main source of power, the increasing numbers of vehicles on the roads are not making the situation better.

"They have contributed to the rise of nitric oxide in Beijing," he said.