A new National Research Council report has stressed that exposure to ozone pollution may result in premature deaths.
Ozone is a key component of smog and can cause respiratory problems and other health effects.
The research committee got guidelines for the study from the U.S. Environmental Protection Agency, asking them for analyzing the ozone-mortality link and assess methods for assigning a monetary value to lives saved for the health-benefits assessments.
The committee carried out a review of recent research, and found that deaths related to ozone exposure are more likely among individuals with pre-existing diseases and other factors that could increase their susceptibility.
But at the same time they discovered that premature deaths are not limited to people who are already within a few days of dying.
Besides, the committee also examined research based on large population groups to uncover how changes in ozone air concentration could affect mortality, specifically to determine the existence of a threshold, i.e. a concentration of ozone below which exposure poses no risk of death.
Thus they concluded that if a threshold exists, it is probably at a concentration below the current public health standard. And as people have individual susceptibilities to ozone exposure, not everyone may experience an altered risk of death if ozone air concentration also changes.
The committee said that future research will try exploring how personal thresholds may vary and the extent to which they depend on a person's weakness.
The committee also stated that the research on short-term exposure does not account for all ozone-related mortality, and the estimated risk of death may be greater than if based solely on these studies.
They added that for a better understanding of all the possible connections between ozone and mortality, further research should address whether exposure for more than 24 hours and long-term exposure, weeks to years, are associated with mortality, including how ozone exposure could impact life expectancy.
And they also indicated that EPA should monitor ozone during the winter months when it is low and in communities with warmer and cooler winters to better understand seasonal and regional differences in risk. More research could also look at how other pollutants, such as airborne particulate matter, may affect ozone and mortality risk.