The evidence supporting a link between air pollution exposure and adverse health outcomes is strong. In particular, exposure to fine particulate matter is associated with worsening of lung conditions (asthma, COPD), increased risk of heart attack, and premature death. While many people know that air pollution poses a significant health risk, we typically associate this risk with highly polluted regions like China, India, and major urban cities. However, evidence is beginning to accumulate that even exposure to low concentrations of pollutants can increase someone’s risk of adverse health effects. These low concentrations are currently considered safe by national pollution standards. Unfortunately, we still don’t know if these results are generalizable to whole populations of people from different ethnic backgrounds or income brackets. To remedy this knowledge gap, a team of researchers from Boston looked at all people from 2000 to 2012 on Medicare in the US to determine whether exposure to low levels of air pollution are associated with an increased risk of premature death. This large cohort allowed them to separate people into groups based on ethnicity and income to determine which populations are most affected by pollution in the US.
This cohort of people comprised over 60 million people spanning different ethnic groups and different median incomes. To estimate each person’s pollution exposure, the team matched their ZIP codes to pollution modelling data from across the US. This pollution data was modelled from satellite images and other sources to predict the average levels of pollution across the US from 2000 to 2012. The highest levels of pollution were seen on the eastern side of the country but these were still below the nationally acceptable levels set by the EPA. The data showed that exposure to PM2.5 (small particulate matter) below the national standard (less than 12 μg per cubic meter) was associated with a 13.6% increased risk of premature death among all people. Stratifying this out based on ethnicity showed that this effect was more pronounced in Blacks, Hispanics, and Asians and overall more pronounced in males than females. The data also showed that the risk for premature death was greater in individuals who were of low income.
This data may be frightening because it suggests that even at our currently accepted standard for air pollution we are still at risk for adverse effects. The good news is that the path to remedying this problem is clear. We need cleaner fuel sources and cars, better pollution management systems with more stringent rules, a plan to tackle climate change and reduce greenhouse gases (which are known to make pollution worse), and a better understanding by politicians on the impact of pollution on the populations health.