No gas Motor bikes- what will it mean?

For me, living in Saigon my real only dislike is the pollution lately. I have no idea what percentage is caused by motorbikes but I would like some breathable air again. Tet has been the only somewhat normal air quality in the 60s but before it was consistently over 150 AQI. 

...I have no idea what percentage is caused by motorbikes but I would like some breathable air again.... - @jrharvey

I recall the gov't had estimated that exhaust emissions from gas powered vehicles (bikes, cars, trucks...combined) in Hanoi to be only about 15% of measured air pollution. I'm thinking there'd be similar readings in Saigon.

...I have no idea what percentage is caused by motorbikes but I would like some breathable air again.... - @jrharvey
I recall the gov't had estimated that exhaust emissions from gas powered vehicles (bikes, cars, trucks...combined) in Hanoi to be only about 15% of measured air pollution. I'm thinking there'd be similar readings in Saigon. - @Aidan in HCMC

Dr Google say: PM2.5 Contribution: Motorbikes generate 60% of the PM2.5 produced by the road transport sector.

A major factor is that roughly 70% of the nearly 8 million motorbikes in Saigon are more than 10 years old and lack modern emission control systems.

They are responsible for an overwhelming 90% to 98% of Carbon Monoxide (CO) and approximately 69% of nitrogen oxides (NOx) emissions from all motor vehicles in the city.

...I have no idea what percentage is caused by motorbikes but I would like some breathable air again.... - @jrharvey

I recall the gov't had estimated that exhaust emissions from gas powered vehicles (bikes, cars, trucks...combined) in Hanoi to be only about 15% of measured air pollution. I'm thinking there'd be similar readings in Saigon. - @Aidan in HCMC

Dr Google say: PM2.5 Contribution: Motorbikes generate 60% of the PM2.5 produced by the road transport sector.

I read this as motorbikes contributing 60%, and cars/trucks/buses 40% of PM2.5 from road transport vehicles. I don't find that surprising when we consider how many more bikes there are compared to other vehicles.

What I recall reading was that that 60%/40% contribution constitutes only 15% of the total PM2.5 count.

Again, and if I recall correctly, the majority of air pollution, i.e. 85% (in Hanoi), was from industry, controlled farm burns, pollution blown in from across borders, as well as other sources.

A major factor is that roughly 70% of the nearly 8 million motorbikes in Saigon are more than 10 years old and lack modern emission control systems.They are responsible for an overwhelming 90% to 98% of Carbon Monoxide (CO) and approximately 69% of nitrogen oxides (NOx) emissions from all motor vehicles in the city. - @SimCityAT

I'll see if I can find the article that the "15% of total PM2.5 count" was in, but I've got my doubts I'll find it.

Wasn't able to find the article I had referenced, but I did find this in one of our local e-rags.

Hanoi's smog puzzle: Vehicle emissions contribute just 15%, officials say

Despite popular belief, vehicle emissions are not the main culprit behind Hanoi's worsening air quality, making up just 15% of total pollution, according to officials, who however say cutting emissions remains urgent.  (link to source)

If vehicle emissions constitute just 15% of Hanoi's air pollution, that means only 9% of that pollution can be attributed to motorbikes (assuming the previously mentioned 60/40% spilt of bikes-to-cars is correct). A total outright ban on gas powered bikes, and the effect it will have on people who depend on their bikes, seems to me to be rather draconian. This push to ban gas powered bikes seems to be more ideologically driven than anything.