Exposure characteristics of airborne particulate matters in Chinese kitchen of a hotel in Hangzhou

Background The hazards of kitchen particles have aroused social concerns, but there are few studies on their distribution characteristics.

Objective This study is designed to explore the time and space distribution characteristics of kitchen particles, including the number concentration (NC), mass concentration (MC), surface area concentration (SAC), and particle size distribution, and provide a reference for assessing the exposure levels and health effects of ultrafine particles among exposed populations.

Methods Particles at different cooking posts were monitored in the Chinese kitchen of a hotel in Hangzhou. The temporal and spatial distribution characteristics of NC, MC, and SAC of particles and the particle size distribution at the fried food posts were analyzed, the individual exposure levels to particles were compared between fried food posts and steaming posts, and the correlations among NC, MC and SAC were evaluated.

Results At the fried food posts, the NC_{10~500 nm} during lunch preparation period and peak lunch period were higher and more fluctuating than that during lunch closing period; the MC_{10~500 nm} during lunch preparation, peak, and closing periods were 0.149, 0.229, and 0.151 mg·m^-3, respectively, fluctuating less than NC_{10~500 nm} throughout the whole lunch period; the SAC_{10~500 nm} during the three periods were 225, 961, and 466 μm²·cm^-3, respectively. The particles within 100 nm accounted for 94.67% of total particles, and in the peak lunch period the particles of 19 nm dominated (mode size). The NC_{20~700 nm} of particles of the fried food posts was higher than that of the steaming posts (P < 0.01), and the mode size of particles of the cooking posts(34.98±2.33) nm was higher than that of the steaming posts(30.11±2.17) nm (P < 0.01). The correlation between SAC_{10~500 nm} and NC_{10~500 nm} (r=0.703) was stronger than the correlation between NC_{10~500 nm} and MC_{10~500 nm} (r=0.412) and between SAC_{10~500 nm} and MC_{10~500 nm} (r=0.351).

Conclusion The NC, MC, and SAC of particles sampled from fried food posts is related to the operation activities. The number of particles with a particle size less than 100 nm occupies an absolute dominant position in the composition. The strong correlation between SAC and NC suggests that SAC might be a better indicator of air pollution exposure.