Published on September 6th, 2015 | by James Ayre0
“Safe” Levels Of Air Pollution Still Causes Heart Attacks
Here’s yet another reminder of why we are so interested in seeing the EV revolution advance.
Even “safe” levels of particulate and nitric dioxide (NO2) air pollution are associated with a notably increased risk of severe heart attacks, according to new research presented by Dr Jean-Francois Argacha of UZ Brussel-Vrije Universiteit Brussel in Belgium.
The “safe levels” in question are actually well below the recommended limits in Europe currently — which means that a great many people on that continent are probably exposed to such levels (at least occasionally).
The new findings are the result of researchers investigating the effect of short-term exposure to common levels of air pollution on the risk of ST-segment elevation myocardial infarction (STEMI) — which is, for some background here, a particularly dangerous type of heart attack triggered by prolonged blockage of blood supply within the heart. Of all heart attack types, this one features largely the worst prognosis.
Most common air pollution is a mix of particulate matter and pollutant gases (sulfur dioxide, nitric dioxide, and ozone). Particularly small particulate air pollution (PM2.5) has the ability to be absorbed deeply into the lower respiratory tract — it’s a common product of fossil fuel combustion.
Green Car Congress provides more information on the methodology used:
Data on PM10, PM2.5, O3 and NO2 levels were obtained from Belgian Environmental Agency air pollution records. A statistical model called RIO was used to provide a real-time evaluation of air pollution exposure in each part of Belgium with adjustments for population density.
Data on STEMI incidence came from the Belgian Interdisciplinary Working Group on Acute Cardiology (BIWAC) STEMI registry, using STEMI hospitalisation as a proxy indicator. The relationship between pollutants and STEMI was assessed using a case-crossover design and performed by the biostatistics department of Université Libre de Bruxelles (ULB), Brussels, Belgium.
Between 2009 and 2013, there were 11,428 hospitalisations for STEMI. The researchers found that 10 μg/m3 increases in ambient PM2.5 concentrations were associated with a 2.8% increase in STEMI while 10 μg/m3 rises in NO2were associated with a 5.1% increased risk. These associations were only observed in men.
Dr Argacha commented: “The association between STEMI and air pollution was observed within one day of exposure. This was despite the fact that concentrations of air pollutants were within the European air quality standard. It’s possible that only men were affected because of the under representation of women in our study population (less than 25%). Nevertheless, previous studies have demonstrated that blood pressure, arterial stiffness and heart rate variability abnormalities secondary to air pollution exposure are more pronounced in men. Sex differences in obesity and blood inflammation may worsen air pollutant effects but this hypothesis requires further investigation.”
Further analysis showed that those over the age of 75 were particularly affected by PM10 exposure, while those under the age of 54 were more affected by NO2 exposure, interestingly.
“Considering that NO2 is more related to vehicle emissions, one explanation for this finding could be that the younger population may be exposed to excess NO2 from road traffic due to a higher level of social and professional activities. This is the first study to examine the effect of air pollution on STEMI occurrence at a national level using a prospective observational registry of unselected patients. We found that particulate and NO2 air pollution, at levels below European limits, are associated with an increased risk of STEMI. The detrimental impact of NO2 exceeds that of fine particles and raises new public health concerns.”
Interesting work, though not reassuring to those of us that are exposed to levels of air pollution such as this regularly (which is the vast majority of us reading this, I’m guessing). Yet another quill in the bonnet for electric vehicles. Here’s to hoping that the next generation of EVs released see large enough sales to displace gas-powered car use to a significant degree. Though, I’d guess that diesel trucks are really more the issue in this case than cars.