Hanoi has begun to modernise old air-quality monitoring stationsthis year under a plan approved by the Hanoi People's Committee.

The old system was believed to be complicated and show little effectiveness in monitoring air quality.

The replacement programme is scheduled to finish by 2020 with a totalnumber of 360 modern stations instead of more than 1,250 old ones.

The two-phrase plan aims to improve data collection and analysis ofchanges to air-quality and meteorological elements, therefore givingsolutions to reducing air pollution and protecting community health inthe city.

There will be seven automatic air-quality monitoring stations, five more than are currently in use.

The committee has assigned the city's Natural Resources and Environment Department to direct the plan.

The move was taken after air quality in Hanoi was shown to beworsening in a report on the city's environment situation, which wasreleased by the department in late 2011.

According to thereport, vehicle exhaust emissions including carbon dioxide, volatileorganic compound (VOC) and nitrogen dioxide have been blamed for the airpollution in the capital.

In particular, VOC is believed to contain chemicals which cause long-term negative health impacts for humans.

The compounds in VOC are also found in solvents, cleaning chemicals, building materials and office equipment.

Hoang Duong Tung, director of the Vietnam Environment Administration'sEnvironmental Monitoring Centre, told the local media that dust levelsin most areas of the city had exceeded safe levels in recent years.

Air pollution levels remained high at construction sites and thetraffic intersections of Kim Lien, Giai Phong, Phung Hung and NguyenTrai, he said.

The levels gradually rose with the growing number of vehicles and construction sites, he said.

Under the plan, the department will have to build and operate three airquality monitoring stations in areas where with high risks to airpollution during the first phrase, which is expected to finish in 2015.

This will ensure the management of the technical apparatus that will be understood and will allow the training of observers.

The second phrase is planned to launch for the period of 2016-20, whereall air-quality monitoring stations will be operating effectively aspart of the national environment monitoring system./.