US EPA

838152 

Journal Article 

Review 

Particulate matter in new technology diesel exhaust (NTDE) is quantitatively and qualitatively very different from that found in traditional diesel exhaust (TDE) 

Hesterberg, TW; Long, CM; Sax, SN; Lapin, CA; Mcclellan, RO; Bunn, WB; Valberg, PA 

2011 

Yes 

Journal of the Air and Waste Management Association
ISSN: 1096-2247
EISSN: 2162-2906 

Taylor and Francis Inc. 

61 

9 

894-913 

English 

22010375 

10.1080/10473289.2011.599277 

WOS:000295344200001 

Diesel exhaust (DE) characteristic of pre-1988 engines is classified as a "probable" human carcinogen (Group 2A) by the International Agency for Research on Cancer (IARC), and the U.S. Environmental Protection Agency has classified DE as "likely to be carcinogenic to humans." These classifications were based on the large body of health effect studies conducted on DE over the past 30 or so years. However, increasingly stringent U.S. emissions standards (1988-2010) for particulate matter (PM) and nitrogen oxides (NOx) in diesel exhaust have helped stimulate major technological advances in diesel engine technology and diesel fuel/lubricant composition, resulting in the emergence of what has been termed New Technology Diesel Exhaust, or NTDE. NTDE is defined as DE from post-2006 and older retrofit diesel engines that incorporate a variety of technological advancements, including electronic controls, ultra-low-sulfur diesel fuel, oxidation catalysts, and wall-flow diesel particulate filters (DPFs). As discussed in a prior review (T. W. Hesterberg et al.; Environ. Sci. Technol. 2008, 42, 6437-6445), numerous emissions characterization studies have demonstrated marked differences in regulated and unregulated emissions between NTDE and "traditional diesel exhaust" (TDE) from pre-1988 diesel engines. Now there exist even more data demonstrating significant chemical and physical distinctions between the diesel exhaust particulate (DEP) in NTDE versus DEP from pre-2007 diesel technology, and its greater resemblance to particulate emissions from compressed natural gas (CNG) or gasoline engines. Furthermore, preliminary toxicological data suggest that the changes to the physical and chemical composition of NTDE lead to differences in biological responses between NTDE versus TDE exposure. Ongoing studies are expected to address some of the remaining data gaps in the understanding of possible NTDE health effects, but there is now sufficient evidence to conclude that health effects studies of pre-2007 DE likely have little relevance in assessing the potential health risks of NTDE exposures. 

Compressed natural gas; Diesel engines; Diesel fuels; Environmental Protection Agency; Gas emissions; Health; Health risks; International cooperation; Nitrogen oxides; Particulate emissions; Risk assessment; Wall flow; Characterization studies; Compressed natural gasses (CNG); Diesel exhaust particulates; International agency for research on cancers; Technological advancement; U.S. Environmental Protection Agency; Ultra low sulfur diesel fuels; Wall flow diesel particulate filters; Particles (particulate matter); carcinogen; diesel fuel; gasoline; natural gas; nitrogen oxide; sulfur; carcinogenic activity; catalyst; chemical composition; diesel engine; environmental protection; exhaust gas; exposure; filter; health hazard; oxidation; particulate matter; priority journal; review; standard; technology