Research report (Health Effects Institute)
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Res Rep Health Eff Inst · Jan 2002
Real-world particulate matter and gaseous emissions from motor vehicles in a highway tunnel.
Recent studies have linked atmospheric particulate matter with human health problems. In many urban areas, mobile sources are a major source of particulate matter (PM) and the dominant source of fine particles or PM2.5 (PM smaller than 2.5 pm in aerodynamic diameter). Dynamometer studies have implicated diesel engines as being a significant source of ultrafine particles (< 0.1 microm), which may also exhibit deleterious health impacts. ⋯ These particles appear to be primarily composed of sulfur, indicative of sulfuric acid emission and nucleation. Comparing the 1992 and 1999 HD emission rates, we observed a 48% increase in the NOx/CO2 emissions ratio. This finding supports the assumption that many new-technology diesel engines conserve fuel but increase NOx emissions.