Fine and ultrafine particle emissions from microwave popcorn

This study characterized fine ( PM 2.5 ) and ultrafine particle ( UFP , diameter < 100 nm) emissions from microwave popcorn and analyzed influential factors. Each pre‐packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3 min. The number concentration and size distribution of UFP s and PM 2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil‐lined original package or a brown paper bag. UFP s and PM 2.5 generated by microwaving popcorn were 150–560 and 350–800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil‐lined original package with a brown paper bag significantly reduced the peak concentration by 24–87% for total particle number and 36–70% for PM 2.5 . A positive relationship was observed between both UFP number and PM 2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9 × 10 10 to 8.0 × 10 10 No./min for total particle number and from 134 to 249 μg/min for PM 2.5 .