Ultrafine particles and nitrogen oxides generated by gas and electric cooking

Objectives - To measure the concentrations of particles less than 100 nm di ameter and of oxides of nitrogen generated by cooking with gas and electric ity, to comment on possible hazards to health in poorly ventilated kitchens . Methods - Experiments with gas and electric rings, grills, and ovens were u sed to compare different cooking procedures. Nitrogen oxides (NO,) were mea sured by a chemiluminescent ML9841A NO, analyser. A TSI 3934 scanning mobil ity particle sizer was used to measure average number concentration and siz e distribution of aerosols in the size range 10-500 nm. Results-High concentrations of particles are generated by gas combustion, b y frying, and by cooking of fatty foods. Electric rings and grills may also generate particles from their surfaces. In experiments where gas burning w as the most important source of particles, most particles were in the size range 15-40 nm. When bacon was fried on the gas or electric rings the parti cles were of larger diameter, in the size range 50-100 nm. The smaller part icles generated during experiments grew in size with time because of coagul ation. Substantial concentrations of NO, were generated during cooking on g as; four rings for 15 minutes produced 5 minute peaks of about 1000 ppb nit rogen dioxide and about 2000 ppb nitric oxide. Conclusions - Cooking in a poorly ventilated kitchen may give rise to poten tially toxic concentrations of numbers of particles. Very high concentratio ns of oxides of nitrogen may also be generated by gas cooking, and with no extraction and poor ventilation, may reach concentrations at which adverse health effects may be expected. Although respiratory effects of exposure to NO, might be anticipated, recent epidemiology suggests that cardiac effect s cannot be excluded, and further investigation of this is desirable.