Measurements Method Baseline     Physical examination   By trained nurses Age, gender, height, weight,     Clinical history   Using a uniform questionnaire Habitat area     Occupation     Environmental exposure Cooking and heating fuels   Cigarette smoking Current/ ex-/ never, (pack years)   Quality of life CAT   Respiratory symptoms Cough, sputum, dyspnea†, wheezing   Medical illness     Pulmonary function test (pre- and post-spirometry)   As per ATS/ERS task force recommendations FEV1/FVC Ratio   FEV1 Liter, % of predicted   FVC Liter, % of predicted   Chest CT scan Inspiratory V950 (%) Wall area (%) Mean lung density ratio   Laboratory test CBC, chemistry, electrolyte, CRP   Blood, urine sample   Storage‡ Every 3 months     Clinical history   Telephone interviews Every years     Clinical history     Pulmonary function test     Every 3 years     Clinical history Clinical history Clinical history Pulmonary function test Pulmonary function test Pulmonary function test Chest CT scan     †Dyspnea is graded with modified Medical Research Council dyspnea scale. ‡Blood and urine sample will be in storage for future genetic study and we have plan to measure the level of heavy metal poisoning (lead, mercury, cadmium). CAT=COPD assessment test, ATS=American Thoracic Society, ERS=European Respiratory Society FEV1=forced expiratory volume in 1 second, FVC=forced vital capacity, V950=volume fraction of the lung below -950 HU, Wall area (%)=wall area/(wall area + lumen area)×100 Mean lung density ratio=mean lung density ratio of full expiration and inspiration CBC=complete blood count, CRP=C-reactive protein.

Table 1: Summary of clinical measures collected in the chronic obstructive lung disease in dusty area cohort.