They go on to note "The authors are also concerned that the concentrations of air pollutants, though below EU threshold values, are still above the proposed guidelines of the World Health Organization (WHO). As a consequence, they demand changes in government policy: Lowering the threshold for acceptable air pollution levels would be a prudent step”
As it happens the Jersey Government web site has a page for air quality in Jersey. It gives just two sites (how representative is that?) - Howard Davis Park and Halkett Place. For today it simply indicates no data available. And there is no link or means to access historic data ! Another fine example of digital government delivering for you . http://www.gov.je/Environment/Protecting
There is an air quality plan and report from 2013 http://www.statesassembly.gov.je/Assembl
In the mean time our sustainble transport policy goes no where and the population is probably getting more obese.
The other document is a French one which indicates the scale of the impacts of pollution http://www.lemonde.fr/planete/article/20
An addendum I've just seen this https://www.theguardian.com/environment/2