In-Home Air Pollution Is Linked to Respiratory Morbidity in Former Smokers with Chronic Obstructive Pulmonary Disease

Abstract

Rationale: The effect of indoor air pollutants on respiratory morbidity among patients with chronic obstructive pulmonary disease (COPD) in developed countries is uncertain. Objectives: The first longitudinal study to investigate the independent effects of indoor particulate matter (PM) and nitrogen dioxide (NO 2 ) concentrations on COPD morbidity in a periurban community. Methods: Former smokers with COPD were recruited and indoor air was monitored over a 1-week period in the participant's bedroom and main living area at baseline, 3 months, and 6 months. At each visit, participants completed spirometry and questionnaires assessing respiratory symptoms. Exacerbations were assessed by questionnaires administered at clinic visits and monthly telephone calls. Measurements and Main Results: Participants (n ¼ 84) had moderate or severe COPD with a mean FEV 1 of 48.6% predicted. The mean (6 SD) indoor PM 2.5 and NO 2 concentrations were 11.4 6 13.3 µg/m 3 and 10.8 6 10.6 ppb in the bedroom, and 12.2 6 12.2 µg/m 3 and 12.2 6 11.8 ppb in the main living area. Increases in PM 2.5 concentrations in the main living area were associated with increases in respiratory symptoms, rescue medication use, and risk of severe COPD exacerbations. Increases in NO 2 concentrations in the main living area were independently associated with worse dyspnea. Increases in bedroom NO 2 concentrations were associated with increases in nocturnal symptoms and risk of severe COPD exacerbations. Conclusions: Indoor pollutant exposure, including PM 2.5 and NO 2 , was associated with increased respiratory symptoms and risk of COPD exacerbation. Future investigations should include intervention studies that optimize indoor air quality as a novel therapeutic approach to improving COPD health outcomes.Keywords: indoor air; chronic obstructive pulmonary disease; particulate matter; nitrogen dioxide; exacerbations Chronic obstructive pulmonary disease (COPD), the third leading cause of death in the United States and the fifth leading cause worldwide, is expected to become increasingly prevalent in upcoming decades (1, 2). Most COPD is caused by environmental exposures; in developed countries, this exposure is primarily cigarette smoke. After COPD begins, evidence indicates that it can be worsened by other environmental exposures. For example, outdoor particulate matter (PM) concentrations have been associated with an increase in COPD hospitalizations and mortality (3, 4). Similarly, outdoor nitrogen dioxide (NO 2 ) exposure has been linked to worse COPD morbidity, including higher rates of exacerbations (4-6).Although substantial evidence shows that outdoor air pollutants impact COPD, there is much less evidence for the impact of indoor air on COPD, especially in developed countries. Although the Global Initiative for Chronic Obstructive Lung Disease guidelines identify indoor air pollution resulting from burning wood and other biomass fuels as a major risk factor for COPD (7), exposures under these conditions are two to three orders of magnitude higher ...

Indoor Particulate Matter Associated with Systemic Inflammation in COPD

“…In contrast, PM 2.5 concentrations in the present study were consistent with those of nonsmoking homes. In a recent longitudinal study, indoor PM 2.5 was associated with respiratory symptoms, rescue medication use and exacerbations [13]. The current study extends these findings and adds evidence that indoor PM is associated with systemic inflammation in COPD.…”

“…As a result, the impact of indoor air upon these predominantly home dwellers may be much greater than our current knowledge of the effects of ambient pollution. Thus far, studies of indoor air quality and COPD have largely focused on the influence of biomass burning in developing countries, with isolated studies examining the health effects of indoor air quality on COPD in industrialized countries [12] [13]. Evidence that indoor pollutants within homes in the United States may be contributing to respiratory morbidity in individuals with COPD, even in the absence of smoking, is limited.…”

Respiratory Effects of Indoor Heat and the Interaction with Air Pollution in Chronic Obstructive Pulmonary Disease

“…Participants and methods have been described previously (20). Briefly, participants were former smokers with COPD who were recruited from the Baltimore area and studied at baseline and at 3 and 6 months as part of the COPD and Domestic Endotoxin Study.…”

“…Air sampling occurred in the main living area, identified as a room other than the bedroom where the participant reported spending the most time. Additional methods are provided in the online supplement and in a prior publication (20). Outdoor temperature, humidity, and pollution concentrations (PM, NO 2 , and ozone) were obtained from publicly available data sets provided by the National Oceanic and Atmospheric Administration and the Environmental Protection Agency (see Table E1 in the online supplement) (23,24).…”

Physical Activity and Air Pollution Exposures in the Urban Environment

“…Exploring the relationship between physical activity and additional pollutant exposures would help further elucidate the risks and benefits of encouraging physical activity in an urban, polluted environment. In addition, although outdoor air pollution continues to be highly correlated with increases in morbidity and mortality worldwide, a high percentage of the Western population spends the majority of their time indoors (16), and prior research suggests that exposure to indoor pollution can also worsen COPD and asthma (17,18). As a consequence, accounting for indoor air pollution exposures is a key part in estimating an individual's overall pollution exposure, and the results of the Fisher article highlight the need to explore the relationships between in-home pollution concentrations and personal activity behavior on respiratory disease morbidity.…”