III. ENVIRONMENT MONITORING AND URBAN PLANNING
A. Environmental quality in Shanghai
(a) Ambient noise
Figure 27. The average equivalent sound levels
Figure 28. Comparison of ambient noise in recent years
Figure 29. Comparison of high air ambient noise in recent years
(b) Traffic noise
A comparison of monitoring data for recent years shows that traffic noise has been alleviated to a certain extent, despite the sharply increasing traffic volume in Shanghai. Especially in 1994, the daytime traffic noise decreased by 2 db(A). The main causes of this were: (1) operation of the Inner Ring Road (2) improvement in some of the roads in the urban area. (3) trucks were only permitted at night in Zhongshfm Road. (4) in some streets, measures were introduced to improve the traffic flow, such as pedestrian passages, one-way traffic, and no left-turns. (5) installation of acoustic celotex boards along the Inner Ring Road and a prohibition on the use of vehicle horns in some areas.
The traffic noise pollution in Shanghai is assessed by the traffic noise pollution index (TNPI)*. The day-time NPI is 1.03 and night-time 1.24, which meet the D grade or E grade limits respectively. This assessment indicates that noise pollution is still severe.
Figure 30. Comparison of traffic noise in recent years
Table 4. TNPI grade standard
(c) Noise in different functional zones
Following GB3096-93, the Ambient Noise Standard in Urban Area, the monitored noise can meet the standard limits in class 2 zones where there is a cross-section of residential, commercial, and industrial land uses. In class one zones, which are for residences and administration, and in class 3 zones for industrial use, only the night-time noise exceeds the standard. The overall trend shows that ambient noise pollution in different functional zones has been alleviated.
* Definition of traffic noise pollution index caused