This dataset contains particle number concentration (PNC) measurements made using a hand held sampler on public transport routes in Bangkok, Thailand for the Ultrafine and Submicron Particles in the Urban Environment in Thailand project. PNC was measured using a TSI 3007 hand held particle counter on a defined public transport route, each journey consisted of nine stages:

1. Walking from the Chulbhorn Research Institute (13.879763°, 100.577923°) to the Lak Si railway station (13.883559°, 100.58
0674°).
2. Travelling on the State Railway of Thailand South from Lak Si railway station to Hua Lumphong railway station (13.739527°
, 100.516820°).
3. Walking from Hua Lumphong railway station to Hua Lumphong MRT undergound station (13.737864°, 100.517173°).
4. Travelling on the MRT underground train East (blue line) from MRT Hua Lumphong station to MRT Sukhumvit Station (13.73857
9°, 100.561544°).
5. Walking from the MRT Sukhumvit underground station to the Asok BTS Skytrain overground station (13.737076°, 100.560393°).
6. Travelling on the BTS Sukhumvit line North from Asok BTS station to Mo Chit BTS station (13.802621°, 100.553829°).
7. Walking from BTS Skytrain overground station to Mo Chit bus stop (13.803730°, 100.554085°)
8. Travelling on the public bus North from the Mo Chit bus stop to the Miracle Grand bus stop (13.876419°, 100.576880°)
9. Walking from the Miracle Grand bus stop back to the starting position at the Chulbhorn Research Institute.

Data was collected at 1 m height from ground at 1 s sampling intervals. The data covered three seasons in Bangkok, hot, cool
and rainy, from May 2018 until November 2018. Measurements were taken by the staff of the Toxicology group in the Chulabhorn Research Institute, Thailand and the Atmospheric Chemistry Research Group in the University of Bristol, UK. NE/P014674/1