Influence of pollution reduction interventions on atmospheric PM2.5: A case study from the 2017 Xiamen

Abstract

To investigate the influence of pollution control on particulate matter with a diameter ≤2.5 μm (PM2.5), 40 samples were collected before and during the 2017 BRICS summit (BRICS) in an urban and a suburban area of the city of Xiamen, China. The average urban and suburban area PM2.5 concentrations during the BRICS were 26.3% and 35.9% lower than those before the summit, respectively. Chemical characteristics of PM2.5, such as water-soluble ions (WSIIs), organic and elemental carbon (OC and EC), macro elements and trace elements (inorganic elements), were measured. WSIIs and organic matter accounted for the highest proportions in PM2.5. During the BRICS, concentrations of WSIIs, OC, EC and inorganic elements decreased by 17.6%, 39.0%, 42.9%, 44.1% in urban areas and decreased by 0.9%, 35.1%, 53.8%, 79.4% in suburban areas. The influence of primary sources on WSIIs and carbon aerosol decreased and secondary formation increased. High O3 concentrations played an important role in the formation of secondary aerosols. However, the contribution of inorganic element sources did not noticeably change according to Pb–Sr-Nd isotope analysis. Pollution control during the BRICS was effective but not sufficient to reduce health risk from heavy metals in PM2.5, and carcinogenic risks from Cr, Cd, and As exceeded the safety value (10−6).