Table 1.

Characterization and data summary of selected pollutants measured at the St. Louis-Midwest Supersite/Tudor Ave. AQS monitoring location, 1 June 2001–30 April 2003.^a

Pollutant	Abbreviation	Unit	Temporal metric	No. of days	Mean ± SD	Percent PM2.5b	Formation type	Dominant source at the St. Louis-Midwest supersite/Tudor Ave. site
Fine particles and components
Total PM2.5 mass	PM2.5	μg/m3	24-hr avg	683	18.0 ± 8.3	100	Both	Multiple sources
Major ions
Sulfate	SO42–	μg/m3	24-hr avg	694	4.0 ± 3.1	22	Secondary	Secondary formation
Nitrate	NO3–	μg/m3	24-hr avg	679	2.2 ± 2	12	Secondary	Secondary formation
Carbon
Organic carbon	OC	μg/m3	24-hr avg	680	3.8 ± 1.9	21	Both	Multiple sources
Elemental carbon	EC	μg/m3	24-hr avg	666	0.8 ± 0.5	4	Primary	Mobile sourcec
n-Alkanes
n-Octacosane	Oct (nC28)	ng/m3	24-hr avg	668	1.15 ± 1.84	0.006	Primary	Point sourcec
n-Nonacosane	Non (nC29)	ng/m3	24-hr avg	679	2.57 ± 3.28	0.014	Primary	Point sourcec
Hopanes
17α(H),21β(H)-29-Norhopane	Nor (C29αβ)	ng/m3	24-hr avg	679	0.53 ± 0.43	0.003	Primary	Mobile sourcec
17α(H),21β(H)-Hopane	Hop (C30αβ)	ng/m3	24-hr avg	680	0.35 ± 0.27	0.002	Primary	Mobile sourcec
PAHs
Chrysene	Chry (C18H12)	ng/m3	24-hr avg	679	0.38 ± 0.4	0.002	Primary	Winter combustionc,d
Benzo[b+k]fluoranthene	BbkF (C20H12)	ng/m3	24-hr avg	681	0.64 ± 0.65	0.004	Primary	Point sourcec
Benzo[a]pyrene	BaP (C20H12)	ng/m3	24-hr avg	672	0.22 ± 0.42	0.001	Primary	Winter combustionc,d
Indeno[1,2,3-cd]pyrene	IcdP (C22H12)	ng/m3	24-hr avg	667	0.29 ± 0.35	0.002	Primary	Point sourcec
Metals and metalloids
Silicon (metalloid)	Si	ng/m3	24-hr avg	677	125.9 ± 214.8	0.70	Primary	Soilc
Potassium (alkali metal)	K	ng/m3	24-hr avg	677	72.8 ± 86.2	0.40	Primary	Area or nonlocal point sourcee
Calcium (alkaline earth metal)	Ca	ng/m3	24-hr avg	677	125.1 ± 88.8	0.70	Primary	Area or nonlocal point sourcee
Iron (transition metal)	Fe	ng/m3	24-hr avg	677	126.0 ± 99.6	0.70	Primary	Point sourcee; steel processingf
Copper (transition metal)	Cu	ng/m3	24-hr avg	677	24.2 ± 49.9	0.13	Primary	Point source; copper productionf
Zinc (transition metal	Zn	ng/m3	24-hr avg	677	44.9 ± 74.4	0.25	Primary	Point sourcee; zinc smeltingf
Lead (basic metal)	Pb	ng/m3	24-hr avg	677	19.3 ± 36.5	0.11	Primary	Point sourcee; lead smeltingf
Criteria gases
Ozone	O3	ppb	8-hr max	679	36.2 ± 19.7	—	Secondary	Secondary formation
Carbon monoxide	CO	ppm	1-hr max	683	1.0 ± 0.7	—	Primary	Mobile source
Nitrogen dioxide	NO2	ppb	1-hr max	676	31.3 ± 9.3	—	Secondary	Mobile source
Sulfur dioxide	SO2	ppb	1-hr max	694	27.0 ± 37.7	—	Primary	Power plant
Abbreviations: avg, average; max, maximum. aMeasurements of PM2.5 and PM2.5 components made by St. Louis-Midwest Supersite instrumentation, and measurements of criteria gases (O3, CO, NO2, and SO2) made by Tudor Ave. AQS instrumentation; all descriptive statistics exclude data from 4 July 2001, 4 July 2002, and 5 July 2002. bMean percentage of total PM2.5 mass that each PM2.5 component represented over the study period. cJaeckels et al. (2007). dFor example, natural gas combustion due to residential heating. eSnyder et al. (2009). fLee et al. (2006).