HealthyCar.org — Methodology

A portable X-Ray Fluorescence (XRF) device was used to analyze the elemental composition of vehicle and child car seat components in this guide. A total of 11 components from each vehicle were selected for sampling, including: the steering wheel, shift knob, armrest/center console, dashboard, headliner, carpet, seat front, seat back, seat base, hard and soft doortrim. Vehicle ratings were calculated based on the XRF results from the 11 vehicle components that were tested on all vehicles. Vehicle samples were taken over two testing periods. The first included vehicles of model years 2006 and 207 sampled from October to December of 2007. The second sampling phase was conducted from April to June of 2008 and included vehicles with model years ranging from 2007 to 2009. Due to constant turnover of vehicles on a dealer's lot, we were restricted by the model years present on the lot on the day of sampling.

Child car seats were evaluated using a similar method. The car seats sampled included all of the on-the-shelf models available at several major national retailers in Michigan. Child car seats were sampled in January 2007 (2007 model seats) and June 2008 (2008 model seats. The major components in each car seat were sampled, including the seat cushion, foam backing, seat base, seat belt clip and sun shade (when available). Different components were analyzed for different types of car seats. For example, infant seats include sun shades, whereas convertible and booster seats do not. Car seat ratings were calculated based on the XRF results from the components that were sampled on all seats of the same type. The components were selected based on the following criteria:

Potential of exposure, i.e. components that drivers or passengers come in contact with, that are subject to abrasion, or that otherwise release vapors or particles to the environment;

Surface area and relative size of component;

Potential to off-gas or degrade during heat and/or UV-ray exposure;

Ease of access to component for sampling.

For both vehicles and child car seats, the elements tested for include: Antimony, Arsenic, Bromine, Chlorine, Chromium, Cobalt, Copper, Lead, Mercury, Nickel and Tin. These components were chosen for two primary reasons: 1) They could be easily and quickly identified using non-destructive methods. Sampling for this project was limited to new vehicles, which prevented the use of any testing that would damage vehicle components. 2) These elements have already been subject to regulatory restrictions and/or voluntary limits by industry associations or third party environmental certification organizations. These "Chemicals of Concern" may be of impact to the environment and health during all phases of a product's lifecycle, including production, use and end-of-life.

Vehicle testing methods in 2006 differed slightly from testing in 2008. In 2006, 15 vehicle components were analyzed and 12 were included in the final vehicles rankings. In 2008, 11 were sampled and included in the rankings. Components eliminated from test results include: body sealer, wiring, window seal and wheel weights. The interior vehicle components that would directly affect consumers when driving or riding in the vehicles.

All previous vehicle rankings (from 2006 and 2007 model year vehicles) were recalculated using the revised methodology contained in the 2008 report. Scores were recalculated to allow comparison with the ranking of 2008 and 2009 model years vehicles. In most instances the change in methodology resulted in insignificant changes in the final rankings of the vehicles.

For a detailed description of the HealthyCar.org vehicle and child car seat rating systems and methodology, download the fully referenced report.