Human activities such as burning fossil fuels have been the primary driver of climate change over the past two centuries. Significant shifts in environmental phenomena such as weather patterns can result from greenhouse gases that, when emitted, trap heat and raise temperatures on Earth. It will take a considerable financial investment on the part of businesses and institutions to curb climate change. However, emerging evidence suggests that climate change may not be the only feature of greenhouse gas emissions we should be concerned about. As the debate surrounding global warming and climate change continues to evolve, the question of how greenhouse gas emissions impact organ systems such as the cardiovascular system has sparked intensive investigation.
We know that long-term exposure to polluting chemicals in the air can damage organ systems such as the cardiovascular system. However, a pooled analysis published September 2021 reviewed data from cohort studies from northwestern European countries and found that, even when kept at concentrations significantly lower than current European Union standards and World Health Organization (WHO) guideline limits, long term exposure to air pollutants such as Nitrogen Dioxide is associated with increased incidence of stroke and coronary heart disease. These results are contrary to the results of prior studies, which showed either a weak or non-existent association between cardiovascular disease and Nitrogen Dioxide exposure. Although there were some limitations to the study, such as a comparably small scale of exposure and differences in the accuracy of cardiovascular diagnosis, the study was comprehensive, with a large sample size and comparability between cohorts.
In April of 2018, the Environmental Protection Agency (EPA) published a final rule concerning Nitrogen Dioxide, in which they opted not to change current standards. They noted that although the case for a causal relationship was stronger than the prior rule regarding an association between long-term exposure and cardiovascular disease, it was nevertheless deemed “suggestive, but not sufficient to confer” a causal relationship. Given the significant global health burden associated with cardiovascular disease, policymakers should note the above recent evidence when it comes time to revise EPA standards around air quality, WHO air quality guidelines, and European Air Quality Standards, especially as they pertain to Nitrogen Dioxide.