Filigrana P, Milando C, Batterman S, et al. - Greater exposures to primary fine particulate matter (PM _2.5 ), oxides of nitrogen (NO _x ) , and black carbon (BC) from highway traffic did not result in a meaningfully higher risk of mortality in persons within 1 km of major highways in the Washington Puget Sound between 2009 and 2013.

• A case-crossover design was used along with the Research Line Source Dispersion Model with spatiotemporally resolved highway traffic data.

• Highly resolved modeled levels of PM _2.5 , NO _x and BC from highway traffic in the hours prior to death were used.

• Neither preceding 24-hour average exposure nor shorter averaging periods was related to mortality.