. Author manuscript; available in PMC: 2012 Jan 9.

Published in final edited form as: Aerosol Sci Technol. 2011 Sep;45(9):1090–1108. doi: 10.1080/02786826.2011.581256

TABLE 6.

Site-specific instrumental regression estimates for PM_2.5

Covariates	Site number
	3	7	17	20	60	Global
Ln(AOD_MODIS) = f (Factors 1, 2, and 3)	0.512^*** (0.400–0.624)	0.898^*** (0.686–1.110)	1 107^*** (0.886–1.328)	1.364^*** (1.090–1.638)	1.721^*** (1.223–2.219)	0.982^*** (0.865–1.099)
Sin(month since January 2000/2006)	–0.222^*** [–0.353–(–0.091)]	–0.238^*** [–0.406–(–0.070)]	–0.178^** [–0.334–(–0.022)]	–0.397^*** [–0.634–(–0.160)]	0.04 (–0.242–0.322)	–0.269^*** [–0.378–(–0.160)]
Cos(month since January 2000/2006)	0.0265 (–0.179–0.232)	0.176 (–0.094–0.446)	0.344^*** (0.121–0.567)	0.445^*** (0.131–0.759)	0.768^*** (0.237–1.299)	0.232^*** (0.065–0.399)
Season dummy (1 for June, July, and August, 0 for the rest)	0.0237 (–0.188–0.235)	–0.108 (–0.402–0.186)	0.0443 (–0.250–0.338)	–0.095 (–0.454–0.264)	–0.0356 (–0.453–0.382)	–0.072 (–0.248–0.104)
Constant	3.864^*** (3.595–4.133)	4.084^*** (3.619–4.549)	4.385^*** (3.975–4.795)	4.501^*** (3.944–5.058)	4.813^*** (4.127–5.499)	4.178^*** (3.945–4.411)
Observations	286	236	395	301	212	1430

^***

p < 0.01.

^**

p < 0.05.

Note: Factor 1 = positively correlated surface temperature, dew point, relative humidity, and negative visibility; Factor 2 = relative humidity inversely associated with surface; temperature; and Factor 3 = atmospheric pressure inversely associated with wind speed (see Table 5 for details). 95% confidence limits in parentheses.