An Intercomparison of Measurement Methods for Carbonaceous Aerosol in the Ambient Air in New York City

Figures & data

TABLE 1 Average hourly concentrations of OC, thermal EC, BC, and OM

	Average (μ g/m^3)	Range (μg/m^3)
Sunset Laboratory OC/EC
OC	1.62	0–7.02
Thermal EC	0.85	0–5.47
TC	2.32	0–12.36
Optical EC	0.65	0.10–3.23
R&P 5400 Monitor
OC	1.93	0.26–4.65
Thermal EC	0.55	0–2.62
TC	2.49	0.24–6.56
Aerodyne AMS
OM	4.69	0.72–29.93
STN and ASRC 24-hour filters
OC	1.68	0–4.26
Thermal EC	0.53	0–1.35
TC	2.2	0–4.86
AE-20 Aethalometer
BC	1.01	0.23–5.87

FIG. 1 Diurnal variations of hourly BC and UV-BC concentrations from the two-wavelength AE-20 Aethalometer for (a) average concentrations and (b) median concentrations.

FIG. 2 Comparison between collocated Aethalometer BC concentrations and (a) Sunset thermal EC, (b) R&P 5400 thermal EC, and (c) STN and ASRC 24-hour filter EC concentrations.

FIG. 3 (a) Average hourly Sunset thermal EC, Sunset OC and ozone concentrations in Flushing, New York during January 12–February 5, 2004, and (b) Average hourly Sunset thermal EC, Sunset optical EC and Aethalometer BC concentrations during the same period.

FIG. 4 Comparison between (a) Sunset optical EC and Sunset thermal EC, and (b) Sunset optical EC and Aethalometer BC in Flushing, New York during January 12–February 5, 2004.

TABLE 2 Collocated comparisons among semi-continuous and filter based carbon measurements

	Sampler
Measurement	y	x	Regression slope ± Standard Error	Intercept ± Standard Error	Correlation (r)	Number of Pairs
OC	Sunset	STN & ASRC	0.75 ± 0.76	0.08 ± 0.36	0.82	16
	Sunset	R&P 5400	0.98 ± 0.11	−0.47 ± 0.17	0.66	327
	R&P 5400	STN & ASRC	0.60 ± 0.47	0.58 ± 0.82	0.76	17
	AMS OM	Sunset	1.61 ± 0.14	2.08 ± 0.11	0.57	562
	AMS OM	STN & ASRC	1.35 ± 0.90	1.25 ± 1.47	0.87	20
	AMS OM	R&P 5400	1.24 ± 0.18	0.57 ± 0.29	0.6	406
EC	Sunset	STN & ASRC	1.21 ± 0.44	−0.03 ± 0.13	0.97	16
	Sunset	R&P 5400	1.35 ± 0.12	0.06 ± 0.04	0.78	327
	R&P 5400	STN & ASRC	0.49 ± 0.46	0.09 ± 0.26	0.88	15
TC	Sunset	STN & ASRC	0.86 ± 0.39	−0.06 ± 0.69	0.88	16
	Sunset	R&P 5400	1.31 ± 0.10	−1.15 ± 0.15	0.77	327
	R&P 5400	STN & ASRC	0.77 ± 0.58	0.35 ± 1.37	0.91	16

FIG. 5 Comparison of hourly measured OC and thermal EC from (a) Sunset OC/EC analyzer, and (b) R&P 5400 carbon monitor.