A new study suggests that some of the benefits of exercise may be lost depending on where we live.

Scientists, in a study published in the journal BMC Medicine, found that people who exercise regularly but also live in polluted air lose half of the benefits of exercise.

In the study, conducted at University College London, scientists studied data from more than 1.5 million people over 10 years, from the UK, Taiwan, China, Denmark and the US.

The study looked at the presence of PM2.5 (pollutant particles that can get stuck in the lungs and enter the bloodstream) along with exercise habits.

The researchers found that people who did at least two and a half hours of moderate to vigorous exercise each week were 30 percent less likely to die prematurely than those who did not exercise.

However, if these individuals live in an area with high levels of fine particulate matter (more than 25 micrograms per cubic meter), these chances drop from 30 percent to 12 to 15 percent.