The chronic effects of particulate matter (PM2.5, PM10 and PM1) on the morbidity and mortality of cardiovascular and respiratory diseases in LMICs: a systematic review and meta-analysis

Abstract Background Particulate matter (PM) pollution and various air pollutants have been most strongly linked to adverse health effects. Combined estimates of the health effects of particulate matter exposure from quantitative assessments is important, but the evidence of the association in low-and middle-income countries (LMICs) remains unclear. This study is the first to focus on the particulate matter pollution in LMICs and include the effects of low-particle size matter such as PM1. Methods We systematically searched Pubmed, Web of Science and Embase from database inception to 11 Apirl 2021. Two investigators independently sifted through the literature and extracted data to identify eligible studies. We included cohort studies and case-control studies studied health effects of PM1, PM2.5 and PM10 on cardiovascular and respiratory morbidity and mortality. Random effects meta-analysis were conducted. Results We included 38 publications on long-term PM exposure in our systematic review after screening 1977 articles.The most majority uses the cohort study design (n=35), with 3 articles use a case-control study design. The results shows that PM2.5 and PM10 was positively associated with cardiovascular and respiratory diseases at increased levels. (1) Increased PM1 concentrations were associated with cardiovascular diseases for male. (2) With per 10 µg/m3 increase in PM2.5 concentrations, cardiovascular mortality was increased by 13% (95% CI: 1.08, 1.19), respiratory mortality was increased by 10% (95% CI: 1.02, 1.18). (3) The cardiovascular mortality was increased by 17% (95% CI: 1.00, 1.37) per 10 µg/m3 increase in PM10, respiratory mortality was increased by 28% (95% CI: 1.10, 1.49). Conclusion PM exposure have adverse effects on both the morbidity and mortality of cardiovascular and respiratory diseases in LMICs.. On the basis of previous studies, this study added the impact of PM1 on health, which is innovative. The development of new Air Quality Guilelines may have a positive impact on health of population in LMICs.