Air quality eases up a bit during the wet season, but smoke from crop
burning during harvest season will make Ho Chi Minh City (HCMC) an uncomfortable place to stay during summer months.
The ratio of the three isotopes rapidly change seasonally due to the C4 crops, Sugar Cane, Maize etc
during harvest — and the data Ferdinand Engelbeen supplies doesn't take into account the 1950 ′ s, 1960, s and 1970, s when sugar cane was
burnt off.