It depends on how you define "affected" and whom you ask! It's a very small fraction of those "affected" by traffic pollution. However, both figures are impossible to calculate.
how many people were affected
thousands of people are affected
how many people are affected by MS (multiple sclerosis)
1 out of 4 people are affected
3000000 people are affected
Most people in the world are affected by dust. (Affected = it influences them in some way)
85 people were affected by H1N1
All people on earth are affected by their environment.
Rohypnol is illegal in the United States, so it is hard to tell how many people are affected by it.
About 2.2 million people are affected by the disease worldwide.
273 people