Objective To study the short-term exposure to ambient particulate matter less than 10 μm in aerodynamic diameter (PM₁₀) on daily mortality in residents of six typical cities in central and western Inner Mongolia Autonomous Region (Inner Mongolia) to provide evidence for the development of air pollution control policies.

Methods Data on daily mortality of permanent residents in six typical cities in central and western Inner Mongolia during 2017 – 2021 were collected from the Death Registration and Reporting Information System of municipal disease prevention and control centers, and data on daily meteorological conditions were collected from the municipal meteorological bureaus of the six cities, including Hohhot, Baotou, Ordos, Bayannur, Wuhai, and Alxa League. The daily average atmospheric PM₁₀, sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and ozone (O₃) during the same period were calculated from the detection records of 24 national air pollutant monitoring stations in the six cities. A generalized linear model was used to quantitatively assess the relationship between PM₁₀ exposure and daily mortality among residents of these cities, with stratified analysis by gender, age, education, and marital status.

Results For the six cities during the 5-year period, the daily mean PM₁₀ concentration was 89.17 ± 84.71 μg/m³; the daily mean number of total non-accidental deaths, deaths from respiratory diseases, and deaths from circulatory diseases were 71 ± 15, 10 ± 4, and 34 ± 10, respectively. Single-day lag effect analysis showed that a 10 μg/m³ increase in daily mean PM₁₀ concentration was associated with increased total non-accidental mortality (excess risk ER = 0.11%, 95% confidence interval 95%CI: 0.03% – 0.20%) and circulatory disease mortality (ER = 0.12%, 95%CI: 0.03% – 0.20%) at lag day 0 in all residents and increased non-accidental mortality in female residents (ER = 0.17%, 95%CI: 0.05% – 0.30%), older residents ≥ 65 years (ER = 0.15%, 95%CI: 0.05% – 0.25%), residents with a junior high school education or less (ER = 0.12%, 95%CI: 0.02% – 0.22%), and unmarried residents (ER = 0.25%, 95%CI: 0.11% – 0.39%). Cumulative lag effect analysis showed that a 10 μg/m³ increase in daily mean PM₁₀ concentration was associated with increased total non-accidental mortality (ER = 0.25%, 95%CI: 0.08% – 0.42%) and circulatory disease mortality (ER = 0.26%, 95%CI: 0.03% – 0.50%) at lag day 7 in all residents and increased non-accidental mortality in female residents (ER = 0.47%, 95%CI: 0.22% – 0.72%), older residents ≥ 65 years (ER = 0.33%, 95%CI: 0.13% – 0.52%), residents with a junior high school education or less (ER = 0.25%, 95%CI: 0.06% – 0.45%), and married residents (ER = 0.32%, 95%CI: 0.03% – 0.61%); a 10 μg/m³ increase in daily mean PM₁₀ concentration was also associated with increased total non-accidental mortality among married residents (ER = 0.34%, 95%CI : 0.07% – 0.61%) on lag day 6.

Conclusion Exposure to PM₁₀ is associated with increased total non-accidental mortality and circulatory disease mortality among all residents and the increased total non-accidental mortality and circulatory disease mortality are much more significant among female residents, older residents ≥ 65 years, residents with a junior high school education or less, and unmarried residents in six typical cities in central and western Inner Mongolia.