Correlations of PM_2.5 and PM₁₀ with emergency hospital visits for respiratory diseases of residents in Urumqi

Background There are close correlations between exposure to fine particulate matters (PM_2.5) and inhalable particulate matters (PM₁₀) and emergency visits for respiratory diseases, but the correlations may differ across cities.

Objective This study assesses the relationships between ambient PM_2.5 and PM₁₀ concentrations and daily emergency visits due to respiratory diseases in Urumqi.

Methods Data were collected on daily emergency visits due to respiratory diseases, meteorological variables, and atmospheric pollutants in the city from 2016 to 2018. Meteorological data included daily average temperature and relative humidity. Atmospheric pollution data included daily mean concentrations of PM_2.5, PM₁₀, SO₂, NO₂, and CO and maximum 8 h O₃. The emergency medical service usage data were sourced from the Urumqi Center for Disease Control and Prevention, and the meteorological and atmospheric pollution data were from six national monitoring stations in the urban area of Urumqi. Generalized additive model was used to analyze the relationships between PM_2.5 and PM₁₀ concentrations and daily emergency visits due to respiratory diseases with adjustment for time trends, meteorological factors, and day of the week, and risk estimates at individual (lag0-lag7) and cumulative (lag01-lag07) lag days were expressed as excess risk (ER) with 95% confidence interval (95% CI).

Results A 10μg·m^-3 increase in concentrations of PM_2.5 and PM₁₀ at lag07 day corresponded to an increase of 1.99% (95%CI:1.18%-2.80%) and 1.43% (95% CI:0.76%-2.10%) in daily emergency visits due to respiratory diseases respectively. The results of gender stratification analysis showed that a 10 μg·m^-3 increase in concentrations of PM_2.5 and PM₁₀ at lag07 day corresponded to an increase of 2.18% (95% CI:1.16%-3.21%) and 1.50% (95% CI:0.66%-2.35%) for male patients respectively; a 10 μg·m^-3 increase in concentrations of PM_2.5 and PM₁₀ at lag04 day corresponded to an increase of 1.33% (95% CI:0.15%-2.52%) and 1.02% (95% CI:0.05%-2.00%) for female patients respectively. The results of age stratification analysis showed that for the ≥ 65 years age group, a 10 μg·m^-3 increase in concentration of PM_2.5 at lag06 day and PM₁₀ at lag07 day corresponded to an increase of 1.67% (95% CI:0.76%-2.57%) and 2.11% (95% CI:1.19%-3.04%) in daily emergency visits due to respiratory diseases, and for the < 65 years age group, a 10 μg·m^-3 increase in concentration of PM_2.5 at lag05 day and PM₁₀ at lag02 day corresponded to an increase of 1.97% (95% CI:0.59%-3.36%) and 1.44% (95% CI:0.67%-2.21%), respectively.

Conclusion PM_2.5 and PM₁₀ concentrations may increase the risk of respiratory diseases among residents in Urumqi, and men and the age group ≥ 65 years are more sensitive to such exposures.