Office of FreedomCAR and Vehicle Technologies Health Impacts Program (Poster)

Conference · Tue Aug 01 00:00:00 EDT 2006

OSTI ID:896981

Lawson, D R; Eberhardt, J J

We evaluated day-of-week differences in mean concentrations of ozone precursors [nitric oxide (NO), nitrogen oxides (NOx), volatile organic compounds (VOC) and carbon monoxide (CO)] at monitoring sites in 23 states comprising seven geographic focus areas for the years 1998-2003. We used Wednesdays to represent weekdays and Sundays to represent weekends; we also analyzed Saturdays. Statistical t-tests applied to every monitor showed substantial and statistically significant differences between Wednesday and weekend mean concentrations of ozone precursors in all study areas. At half the sites, nine-hour (6 am through 3 pm) mean concentrations of NO, NOx, and CO declined by at least 65, 49, and 28 percent, respectively, from Wednesdays to Sundays. Large reductions in mean concentrations of ozone precursors on weekends did not reduce mean concentrations of peak ozone significantly, and in many areas, mean peak ozone increased on weekends. Ozone accumulation began earlier on Sundays than on Wednesdays, on average. We also evaluated day-of-week differences in mean concentrations of fine particle and nitrate at available monitoring sites for the same time period and same geographic focus areas. Based on the monitors differences in Wednesday and Sunday means, PM nitrate showed almost negligible weekend decline, despite large NO and NOx declines.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC36-99-GO10337
• OSTI ID: 896981
• Report Number(s): NREL/PO-540-40447; TRN: US200704%%128
• Resource Relation: Conference: Prepared for the 2006 Diesel Engine Efficiency and Emissions Research (DEER) Conference, 20-24 August 2006, Detroit, Michigan
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
33 ADVANCED PROPULSION SYSTEMS
54 ENVIRONMENTAL SCIENCES
CARBON MONOXIDE
DIESEL ENGINES
EFFICIENCY
MONITORING
MONITORS
NITRATES
NITROGEN OXIDES
ORGANIC COMPOUNDS
OXIDES
OZONE
VOLATILE MATTER
OZONE PRECURSORS
NITRIC OXIDE (NO)
NITROGEN OXIDES (NOX)
VOLATILE ORGANIC COMPOUNDS (VOC)
CARBON MONOXIDE (CO)
MEAN CONCENTRATIONS
PARTICULATE MATTER
Transportation