The study found "significant associations" between particulate matter - tiny particles emitted from such sources as diesel trucks - and child mortality. In one instance, after two days of high pollution and particulate matter at Ciudad Juarez, opposite El Paso, Texas, infant mortality jumped sharply among children with the lowest socio-economic status, but did not jump among those at the high end of the scale. Speculation is that more affluent children were able to get better medical attention, if necessary, and also stay indoors with air conditioning during times of high pollution alerts.
NAFTA supporters say that truck emissions are exacerbated in border areas because of long waiting and idling times endured by trucks at border crossings and that faster crossings will help alleviate smog. They also claim that trucks are only one contributor to smog in these areas and that cars are a major factor, too.
