Abstract:
Thirty-six air pollutants with established enterprise boundary limits were screened out from more than 40 national emission standards for stationary air pollutants sources and local emission standards for odor pollutants. A method suitable for limit analysis was proposed, and a reference interval was set based on the ambient multimedia environmental goals (AMEG). The difference in the occupational exposure limits time-weighted average allowable concentration (TWA) of chemical harmful factors between China and the United States was compared and analyzed. The results showed that the 36 air pollutants could be divided into three categories. Firstly, there were 8 pollutants that appeared in the national integrated emission standards for air pollutants and other standards that had been formulated and published for a long time with loose limits. Secondly, there were 13 pollutants whose limits were not affected by olfactory thresholds, among which the limits of 12 pollutants were close to 8.4 times of AMEG estimation. Thirdly, there were 15 pollutants whose limits were affected by olfactory thresholds, among which the limits of some pollutants were close to AMEG estimation, and some were close to olfactory thresholds. Among the 255 chemical harmful factors involved in the comparative analysis, there were 44 chemical harmful factors with TWA equivalent in China and the United States, accounting for no more than 20 percent, nearly 85 percent with a difference within ±1 time, and 7 percent with a difference of more than ±5 times. The research showed that the enterprise boundary limits in the current air pollutant emission standards had effectively protected human health and ecological environment. However, the standards that had been formulated and published for a long time with loose limits, as well as limits of the standards higher than olfactory thresholds, should be studied to analyze the reasonableness of the limits. Occupational exposure limits data from more sources should be widely collected and their applicability should be analyzed when formulating the limits of air pollutants at enterprise boundaries.