Around 5% fewer adults were admitted to hospital with severe asthma in each of the three years after the ban was introduced in July 2007.
The study, published in the journal Thorax, is the largest to date to examine the effect of the smoking ban on asthma admissions in adults.
Earlier research found admissions among children dropped 12.3% immediately after the ban.
Second-hand smoke can exacerbate asthma symptoms, leading to hospital admissions.
Researchers from the University of Bath looked at how many emergency admissions for asthma occurred across different regions of the UK between April 1997 and December 2010.
After adjusting data for season, region, population size and long-term trends, they detected a 4.9% drop in emergency admissions. This equated to approximately 1,900 admissions each year across England.
All regions of the country experienced similar reductions.
Study authors said the findings did not prove the link but are consistent with previous research that attributed improved health to the smoking ban.
The reduction was lower than seen in other countries, although this may be because many workplaces in England already had smoke-free policies.
Authors said the study 'provides further support to a growing body of national and international evidence of the positive effects that introducing smoke-free polices has on public health'.