The 69% with "any respiratory symptom" included 23.3% with no "lower respiratory symptoms." A far smaller percentage of all workers (17.3%) complained of what may be considered the most important respiratory symptom, dyspnea, which was not quantified by any standard scale. Such a reliance on symptoms is subject to recall biases both for symptoms present before 9/11 and for the onset, worsening, and persistence of symptoms after 9/11. Because physical examination and chest radiographs were unrevealing , the only objective results were from Environmental Health Perspectives • VOLUME 115 | NUMBER 2 | February 2007 pulmonary function tests. These were confined to spirometry, which does not provide insight into all aspects of respiratory impairment. The **data** presented by are limited. Mean values for subsets (classified by WTC exposure, previous smoking history, etc.) are not given. Despite the frequency of cough (42.8%), wheeze (15.1%), and chest tightness (15.4%) and the common diagnoses of asthma/reactive airways dysfunction, only 7.6% of all responders showed airway obstruction, defined as a ratio of forced expiratory volume in 1 sec (FEV 1 ) to forced vital capacity (FVC) less than the 5th percentile of the reference population. Unlike virtually all spirometric surveys of a large population (reviewed by , found little difference in impairment by smoking status. Most spirometric impairments were classified as restrictive, uncharacteristic of the symptoms and clinical diagnoses. This frequency of low FVC (22.7%) raises several issues: a) the effects of other clinical factors not reported on, such as obesity; b) technical considerations in subject performance or technician monitoring of the FVC maneuver, despite the investigators attention to these; and c) the appropriateness of the reference-predicted values.