Apparently we can smell other races, not only can they smell westerners
GROUND FIGHTING IN THE VIETNAM WAR
"By 1965, the Viet Cong controlled much of the coast and the border areas with Cambodia and Laos and had heavily infiltrated the Mekong Delta. Both American and North Vietnamese soldiers said they cold smell their enemies before they saw them. "You can't camouflage smell," said one U.S. Marine, "I could smell the North Vietnamese before hearing or seeing them. Their smell was not like yours or mine, not Filipino, not South Vietnamese either. If I smelled that smell again I would know it."
I do think that westerners "sweat" more than Thais, so it could be down to personal hygiene with some people

It is necessary to shower quite a few time on some days in Thailand. I think underwear and T shirts etc only worn once a day max, if that. Mr S used to wear up to 3 a day! The big mistake is not to wash clothes after getting hot and sweaty. Do not even think about hanging them up after wearing in the wardrobe

Also clothes last longer with a wash and rinse with fabric conditioner, no need for a long wash, just a cool wash will do if only worn for a short time.
Also there is the old stale Tobacco / booze stink

that is horrible, lingers everywhere, body, clothes, hair etc. There is also "the old man" smell

I think when people get older, men and women they have to take more care with the personal hygiene side of things. A drop of "Old Spice" round the "mutton chops" is not going to work!
My son was sitting next to a huge man on a flight back from New York once. He told me the smell was unbearable, he could smell a "fat" smell, like burgers & onion and it made him feel sick.
Mr S says I always smell fragrant

Probably it's down to a little help from Chanel No. 5
