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. Author manuscript; available in PMC: 2015 Feb 25.
Published in final edited form as: Eur Respir J. 2010 Oct 14;37(5):1029–1036. doi: 10.1183/09031936.00081410

TABLE 2.

Correlation among air pollutants#

Pollutants PM2.5 PM10 NO2 O3
PM2.5 0.79 0.47 0.61
PM10 0.72 0.49 0.59
NO2 0.65 0.55 0.15
O3 −0.05 0.06 −0.4
#

Pearson correlation coefficients (r) between any two pollutants. The upper un-shaded area represents correlations in warm season (March 16 – June 30, 2005), whereas the lower shaded area shows correlations in cold season (October 1, 2004 – March 15, 2005).

Correlations are estimated using 24hr averages over a 30-day lag before each subject’s FeNO measurement except ozone, which used averages of 10AM–6PM ozone concentrations over a 30-day lag prior to FeNO testing.