Document Detail


Differences between weekday and weekend air pollutant levels in Atlanta; Baltimore; Chicago; Dallas-Fort Worth; Denver; Houston; New York; Phoenix; Washington, DC; and surrounding areas.
MedLine Citation:
PMID:  19189758     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We evaluated day-of-week differences in mean concentrations of ozone (O3) precursors (nitric oxide [NO], nitrogen oxides [NOx], carbon monoxide [CO], and volatile organic compounds [VOCs]) at monitoring sites in 23 states comprising seven geographic focus areas over the period 1998-2003. Data for VOC measurements were available for six metropolitan areas in five regions. We used Wednesdays to represent weekdays and Sundays to represent weekends; we also analyzed Saturdays. At many sites, NO, NOx, and CO mean concentrations decreased at all individual hours from 6:00 a.m. to 3:00 p.m. on Sundays compared with corresponding Wednesday means. Statistically significant (p < 0.01) weekend decreases in ambient concentrations were observed for 92% of NOx, sites, 89% of CO sites, and 23% of VOC sites. Nine-hour (6:00 a.m. to 3:00 p.m.) mean concentrations of NO, NOx, CO, and VOCs declined by 65, 49, 28, and 19%, respectively, from Wednesdays to Sundays (median site responses). Despite the large reductions in ambient NOx and moderate reductions in ambient CO and VOC concentrations on weekends, ozone and particulate matter (PM) nitrate did not exhibit large changes from weekdays to weekends. The median differences between Wednesday and Sunday mean ozone concentrations at all monitoring sites ranged from 3% higher on Sundays for peak 8-hr concentrations determined from all monitoring days to 3.8% lower on Sundays for peak 1-hr concentrations on extreme-ozone days. Eighty-three percent of the sites did not show statistically significant differences between Wednesday and weekend mean concentrations of peak ozone. Statistically significant weekend ozone decreases occurred at 6% of the sites and significant increases occurred at 11% of the sites. Average PM nitrate concentrations were 2.6% lower on Sundays than on Wednesdays. Statistically significant Sunday PM nitrate decreases occurred at one site and significant increases occurred at seven sites.
Authors:
Charles L Blanchard; Shelley Tanenbaum; Douglas R Lawson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of the Air & Waste Management Association (1995)     Volume:  58     ISSN:  1096-2247     ISO Abbreviation:  J Air Waste Manag Assoc     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2009-02-04     Completed Date:  2009-03-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9503111     Medline TA:  J Air Waste Manag Assoc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1598-615     Citation Subset:  IM    
Affiliation:
cbenvair@pacbell.net
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MeSH Terms
Descriptor/Qualifier:
Air Movements
Air Pollutants / chemistry*
Air Pollution / analysis*
Environmental Monitoring
Nitrates / chemistry
Ozone / chemistry
Time Factors
United States
Chemical
Reg. No./Substance:
0/Air Pollutants; 0/Nitrates; 10028-15-6/Ozone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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