Tobacco industry claims that combustion does not occur in heated tobacco products (HTPs), thus the vapors contain only the evaporation products. However, many works report the emission of carbon monoxide, carbonyl compounds, and particulate matter. These are products of incomplete combustion, indicating that combust does occur in HTPs. The first part of this work will synthesize the previous works reporting particle emissions from heated tobacco products. The second part will present the results of the test curried out in four different HTPs found in the Greek market, Glo, iQos, Lil, and Pulzze, using sticks of 6, 9, 5, 4 different flavors, respectively. The particle emissions were determined using a DustTrack and an Ethalometer; the first determines PM1, PM2.5, PM4, PM10 and total PM; the second determines the black carbon fraction of those particles. Different combinations of puff duration, duration between the puffs and device on/off between the puffs are used. The results show that all devices/sticks emit particles. These emissions start after 3 or more puffs, as the heat of the first puffs are used to evaporate the humectants of the sticks. There is a great difference between devices and sticks. The repeatability of these measurements is not very high, probably due to the high content of humectants. The part of black carbon is a very low percentage of the emitted particles.