Evaluation of Land Use Regression Models for Nitrogen Dioxide and Benzene in Four US Cities

Table 2

Median pollutant concentrations (all above method detection limits) in the four cities^a.

Pollutant	El Paso (22 schools)	Detroit (25 schools)	Dallas (24 fire stations)	Cleveland (22 fire stations)
NO2	22 (11, 37)	16 (11, 24)	12 (4, 25)^b	10 (2, 29)^d
			14 (2, 22)^c	18 (0, 25)^e
Benzene	777 (489, 1531)	466 (338, 698)	232 (83, 388)^b	Not measured
			357 (247, 538)^c

^aMedians calculated over all sites and weeks. Units for NO₂ in ppb; benzene in ppt. Minimum and maximum values in parentheses.
^bSummer 2006.
^cWinter 2008.
^dSummer 2009.
^eWinter 2010.