Time Series Analysis on PM_2.5 Pollution Effect on Mortality of Cardiovascular and Cerebrovascular Diseases in Elderly People in Changchun

Objectives To explore the influence of PM_2.5 on the mortality of the elderly sensitive population with cardiovascular and cerebrovascular diseases(CCVd), and provide scientific basis for formulating targeted environmental health prevention and control measures.

Methods Daily death data, environmental monitoring data (including PM_2.5, PM₁₀, SO₂, NO₂, O₃ and CO) and meteorological data (including average temperature and average relative humidity) of Changchun in 2014-2017 were collected. A time series analysis method was used to evaluate the effect of air pollutants on the death from CCVd in the elderly. Excess risk (ER) was used to evaluate the increased risk of CCVd in the population with each increase of 10 μg/m³ (CO=1 mg/m³) air pollutants. SPSS 13.0 was used for descriptive analysis. Spearman correlation analysis was used for correlation test, and R3.5.0 software was used for time series analysis.

Results A total of 26 498 elderly people died from CCVd in Changchun in 2014-2017, with an average of 18 deaths per day. The mean mass concentrations of PM_2.5, PM₁₀, SO₂, NO2, O₃ and CO were 55.9, 93.3, 30.7, 40.8, 89.1 and 1.0 mg/m³ respectively. The concentration of particulate matter exceeded the limit level seriously, and other pollutants were less in exceeding the limit. According to the fitting result of the single-pollutant model, PM_2.5 had a statistically significant impact on the death of the elderly due to CCVd in lag 1 day (P < 0.05), the excess risk (ER) was 0.378%, which showed a significant cumulative delayed effect on lag (1~3) days(P < 0.05), and reached the maximum level on cumulative lag 3 days, and the excess risk (ER) was 0.442%. NO₂ (lag 1, lag 3, and cumulative lag 3 days), O₃ (the same day and cumulative lag(1~3) days), CO (lag 1, and cumulative lag (1~3) days) could increase the risk of dying from CCVd in the elderly. According to the fitting result of the multi-pollutant model, after adjusting PM₁₀, SO₂, NO₂, O₃, CO and all pollutants, the influence of PM_2.5 on the death disappeared (P>0.05).

Conclusions PM_2.5 pollution in Changchun might increase the risk of mortality in elderly people with CCVd, and the risk might be the result of the combination of PM_2.5 with other air pollutants.