Comparison of the time-dependent characteristics between particle mass and particle number emissions during oil heating and emission mitigation strategies

Abstract

It is important to understand the cooking particles emitted over time to mitigate cooking pollution, but current control strategies fail to consider both particle mass and number emissions. Therefore, this study was designed to compare the differences in time-dependent characteristics of particle mass and number emissions and to propose comprehensive mitigation strategies that consider both characteristics. For this purpose, the effects of various factors on both emissions were analyzed, and time-dependent emission rate models were developed. The time-dependent models obtained were statistically significant (P < 0.001), with most R2 values greater than 0.90. The masses and numbers of particles emitted often varied in the opposite direction. During the smoking stage, corn oil exhibited low particle mass emissions while its particle number emission rate (TERn) reached 109#/s. However, at higher temperatures (T > TDM), the percentage difference in TERn with increasing oil volume decreased from 7.1% to 3.5%, while that in PM2.5 emission rate with decreasing oil volume was almost more than 25%. This indicated that the increased oil volumes were more effective in reducing the particle masses emitted from corn oil than in increasing the numbers of particles emitted, and similar conclusions were also drawn for decreasing oil surface area. Overall, oils exhibiting lower particle mass emissions and lower cooking temperatures were recommended for cooking. Lower oil volumes and larger pans should be used at relatively lower temperatures (T < TDM) primarily to mitigate particle number emissions, while higher oil volumes and smaller pans should be used at higher temperatures to control particle mass emissions.