Real-time indoor PM measurements during dust storms and the association with lung function in COPD patients

Abstract

Background. Environmental health research focused on outdoors particular matter (PM) exposure, yet studies indicate that most of the PM exposure occurs indoors. While indoor is affected by outdoor PM, it can be influenced by additional indoor factors. Dust storm (DS) originated PM were suggested to be a significant risk factor for pulmonary morbidity. During the DS patients can be exposed to the extremely high PM even indoors. Aims. Analysis of the association between outdoor and indoor PM during DS and none-DS days, and the effect of the desert dust exposure on patients with Chronic Obstructive Pulmonary Disease (COPD). Methods. Population comprised 86 patients with moderate-severe COPD residing in Beer Sheva city (Negev desert, Israel). Concentrations of PM10, PM2.5, and PM1 were measured inside and outside household during none-DS and DS days. A multivariate regression analysis was used to assess factors associated with indoor PM concentration. Pulmonary function tests were done at the baseline and after the DS. Results. First results (74 households) show very high indoors PM concentrations during DS; PM10 levels reached 1000 µg/m3 while the outdoor levels were 2000 µg/m3. A much stronger correlation was found between outdoor and indoor levels during DS compared with none-DS day: PM10 (DS day: r=0.733, P<0.05 vs. none-DS day: r=0.38, P<0.05), PM2.5 (DS day: r=0.741, P<0.05 vs. none-DS day: r=0.273, P<0.05), PM1 (DS day: r=0.678, P<0.05 vs. none-DS day: r=0.551, P<0.05). The multivariate analysis showed that indoor PM is influenced by outdoor PM and pets presence. FEV1 (forced expiratory volume in 1 second) during DS day was lower in average by 10% than at the baseline. Conclusions. Indoor PM concentrations increase significantly during DS events with a strong correlation to the ambient air. During DS days there is a worsening in lung function of COPD patients, despite the fact the patients spend most of their time indoors.