II. THE ENVIRONMENTAL MONITORING SYSTEM IN SHANGHAI
B. The network of environmental monitoring
Monitoring of environmental and traffic noise is conducted. The former includes urban gridded environmental noise, high air environmental noise and urban functional district noise, with the latter including traffic noise and shipping noise along the Suzhou River.
Since municipal construction continuously proceeds, the urban area constantly grows and the traffic system quickly changes, Shanghai's monitoring sites for gridded environmental noise and traffic noise were rearranged in 1994. Grids were enlarged from one km2 to two km2, thus 214 sites were fixed. The monitoring period is from May to June each year. Daytime monitoring is conducted from 6:00 to 22:00, and nighttime is from 22:00 to 6.00.
There are 11 sites for high air environmental noise, located in different urban districts, and the monitoring period is from October to November. 24-hour monitoring is conducted lasting for a- month.
24-hour monitoring each season is carried to capture the noise in different urban function districts. The number of sites is 32, among which 8 are positioned in type I districts (for residence, administration, education and entertainment), 13 are in type II (mixture of residence, business and industry), and 11 in type III (industrial zones).
Three sites are set up to measure the shipping noise along the urban segment of the Suzhou River. They are at the Caoyang Road Bridge, Hengfeng Road Bridge and Zhapu Road Bridge. Twice each year, once in each half of the year, continuous monitoring is conducted for 24 hours.