Certain Lifestyle Practices Help to Decrease PM Exposure in Patients With COPD

Some lifestyle practices are associated with reduced concentration of particulate matter (PM) with a diameter smaller than 2.5 µm (PM_2.5), which can improve small airway resistance and quality of life in patients with chronic obstructive pulmonary disease (COPD), according to a study published in Scientific Reports.

The researchers noted that PM_2.5 exposure in patients with COPD can result in hospitalizations and mortality. Because of this, they highlighted that reducing outdoor ambient PM_2.5 can benefit patients with COPD, but it is difficult to accomplish as PM concentrations change dynamically over seasons due to changes in wind direction and pollutants. On the other hand, the researchers found that indoor air pollution can be reduced more efficiently at an individual level.

Although PM is such a large issue for patients with COPD, the researchers noted that there is a lack of guidance on how to effectively reduce indoor PM_2.5 and avoid PM_2.5 exposure. As a result, they performed a detailed questionnaire survey about daily habits to reduce PM exposure and measured real-time PM_2.5 concentrations in participants’ homes for 1 year “to elucidate lifestyle behaviors that improve indoor PM_2.5 concentrations and to determine the impact of PM_2.5 concentrations on acute COPD exacerbations.”

Researchers recruited study participants from 4 representative areas of Korea, consisting of 2 metropolitan areas, a clean rural area, and an industrialized area. Those included had to be 40 years or older, have a diagnosis of COPD, and have a forced expiratory volume in 1 second (FEV₁) less than 80% of the predicted value at enrollment; 104 participants qualified.

Participants completed 2 questionnaires, one at enrollment and one at the study’s conclusion, about their indoor and outdoor environments and lifestyle practices implemented to avoid PM exposure. To better understand their indoor environment, the researchers asked about various topics, including the presence of an indoor ventilation method. To better understand their outdoor environment, the researchers asked about the distance from their home to the road and traffic volume. They also had participants respond to 20 lifestyle practice items, ranking them on a scale from 0 (have never practiced) to 7 (practiced every day).

Additionally, to measure indoor PM_2.5 concentrations, the researchers installed sensor-based light scattering measurement devices called InternetofThings (IOT)-based sensors where participants spent the most time in their homes. The data were sent to a server based on IoT throughout the study. They added that outdoor PM concentrations for each participant were gathered from Air Korea, a national air pollution information system, and judged based on their residential address.

Results showed that PM_2.5 concentrations can be affected by seasons, lifestyle practices, and economic status. The researchers found that PM_2.5 concentrations were lower indoors than outdoors in all seasons except summer. More specifically, they found that the difference (mean [SD]) between indoor and outdoor PM_2.5 concentrations was largest in winter (–4.31 [1.02] µg/m³), followed by spring (–1.87 [0.85] µg/m³), fall (–1.20 [0.63] µg/m^₃), and summer (1.27 [0.63] µg/m³).

Also, the PM_2.5 concentration was significantly lower indoors than outdoors in winter, spring, and summer when patients used indoor air filters, opened windows to ventilate the house, and closed windows while driving with internal circulation mode. The researchers also discovered that common daily lifestyle practices among the participants included turning on the kitchen ventilation while cooking (49.0%), washing their hands upon coming home (42.0%), and avoiding secondhand smoke (41.0%).

The researchers found that the higher the economic status and educational level, the greater the difference between indoor and outdoor PM_2.5 concentrations. Differences in economic levels were more pronounced in some lifestyle practices, including checking air quality forecasts (P = .012), checking air filter filters (P = .023), and wearing a mask outside (P = .073). Similarly, differences in education levels were more pronounced across select lifestyle practices, including operating indoor air filters (P = .013), ventilating the home by opening windows (P = .005), and refraining from going outside when the PM_2.5 concentrations were high (P = .079).

Patients who reported checking air quality forecasts every day and wearing a mask when going out had lower small airway resistance, indicating less severe bronchial obstruction. Those whose everyday practices included mopping indoors, going out in places with little traffic, and dusting clothes off when coming home had lower scores on the COPD-specific St George’s Respiratory Questionnaire, indicating a lesser burden of COPD on their overall health and well-being.

The researchers noted several limitations to their study, one being that participants based their questionnaire answers on memories, which can be biased at times. They hypothesized that this may be why only lifestyle practices performed 7 days a week made a significant difference.

Despite its limitations, the study showed that lifestyle practices are associated with indoor PM_2.5 concentrations and can affect clinical outcomes. The researchers concluded by noting that lifestyle practices, such as operating air filters and opening windows for ventilation, help to reduce PM_2.5 concentrations and can be used to reduce exposure of patients with COPD to PM_2.5.

Reference

Kim H, Huh JY, Na G, et al. Lifestyle practices that reduce seasonal PM_2.5 exposure and their impact on COPD. Sci Rep. 2023;13(1):11822. doi:10.1038/s41598-023-38714-5