In his Sept. 25 article, Volkswagen got it right, then wrong, Justin Fox presented an excellent assessment of the impact of the VW fraud in which the company deliberately deactivated emission controls. While he strongly condemns VW, he nonetheless suggests that the increased emissions from the modified VWs is small compared to Icelandic volcano eruptions.
While this may be true as far as quantities are concerned, it avoids the question of impacts. The difference between volcanic NOx and that emitted from cars is that in the latter case the gas is emitted primarily in urban regions where we live and into an atmosphere rich in volatile organic compounds (VOCs). The NOx and VOCs react to produce a vast array of noxious and harmful chemical species in the air that we subsequently breath. In contrast, volcanoes eject their NOx mostly into the upper atmosphere where the chemistry is different and where the products affect us in more subtle ways. In any event, we can’t stop volcanic eruptions, but we can control emissions.
Joseph M. Prospero, professor emeritus, Department of Atmospheric Sciences Rosenstiel School of Marine and Atmospheric Science,
University of Miami