The study noise pollutions at Wongsawang intersection and Rama VII intersection. According Pollution Control Department (PCD) methods. General sound level measurement used for this research and calculate the Leq24br Using the 5-day measurement period. For the result. The Sound level at Wongsawang intersection were exceeding the standard 70 dBA every day. The peak of Leq24br was 80.9 dBA. According the result of PCD. The Sound level at Rama VII intersection were exceeding 2days. Traffic density was a factor that affects the sound level. In addition the maximum sound level (Lmax) of all the measurements were not exceed 115 dBA

Nowadays the majority of environment problem is pollution of vehicle including the noise of engine combustion. For this reason this thesis aims to compare and study the parameters which affect noise reduction on exhaust pipe. Not only reduce the noise pollution but also maintain the efficiency of the engine. These two substances must be considered. Therefore the researcher emphasized to study the parameters on 3 types of muffler with an equal volume: direct reverse and offset type of mufflers. Initiated by data collection the pressure and the velocity in muffler at the speed of engine at 1000 RPM (slow-running engine mode) and 4000 RPM (maximum running engine mode) were investigated. The data were applied into the program that called “SolidWorks” in order to study parameters. In this step the relation between the pressure and velocity of exhaust were represented. In addition the muffler models were selected to manufacture and test by the standard of The Department of Land Transport. As a result there are two major parameters of the muffler. Firstly the metamorphism of the exhaust gas flow direction pleasurably causes the lower noise at the speed of engine at 1000 RPM. Besides an increase of the flow gas distance can diminish noise at the speed of engine at 4000 RPM as well. However this muffler models were tested under the working mode of catalytic device that is standard equipment for automotive vehicles.

The purpose of this research was characterized the noises at North Phra Nakhon campus Rajamangala University of Technology Phra NakhonThailand. The instrument of this study was instrument noises. Volume of noise levels were measured in terms of 15 hr and equivalent sound level (Leq 9 hr). 10 samples of noise levels were collected at Rajamangala University Technology Phra Nakhon from 10 stations. The results shown that the average noises volume of 9 hours were in range of 63.10 to 71.20 dBA by measuring station with highest mean of monitoring Station Building Civil Engineering in the area of Electrical Engineering and Mechanical Engineering were found 67.68 and 67.39 dBA respectively. The results of this study indicated that volume of noises in Rajamangala University of Technology Phra Nakhon were a little bit more than the standard of Pollution Control Department of Thailand and weren’t affected to teaching and learning in North Phra Nakhon campus.