Abstract
Studies have indicated that the adverse effects on human health and the decrease in visibility caused by fine particulate matter (PM2.5) exhibit spatial heterogeneity. Moreover, the environmental effects produced by different chemical compositions of PM2.5 vary on a regional scale. Therefore, understanding the spatiotemporal variations and chemical compositions of PM2.5 is necessary for assessing the regional impacts. Secondary inorganic PM2.5 (iPM2.5) is formed through chemical reactions between the base gas NH3 and acidic gas pollutants (e.g., NO2 or SO2). The major components of iPM2.5 include NH4+, SO42–, and NO3–. To fully comprehend the regional impacts of PM2.5, this research quantifies the spatiotemporal variations of iPM2.5 with the aim of evaluating the contributions from iPM2.5 to PM2.5 in North Carolina (NC). The concentrations (at 34 sites) and chemical components (at 7 sites) of PM2.5 from 2005 to 2014 were extracted from the EPA’s AirData, with the highest concentrations measured in the urban areas of central NC. Notably, PM2.5 concentrations have been significantly reduced over the past 10 years, with a concurrent decreasing trend in iPM2.5. Seasonal variation analysis indicates that PM2.5 concentrations were higher in summer and lower in winter; however, significant variation occurred only between 2005 and 2011. Although iPM2.5 formed the largest mass fraction of PM2.5 for 2005–2011, organic carbon matter (OCM) contributed the dominant share for 2012–2014. Significant seasonal variations in the iPM2.5 mass fractions were also observed, with NO3– and SO42– exhibiting inverse variations. This study links the ambient PM2.5 to various sources by revealing the spatiotemporal variations of PM2.5 and their associated chemical compositions in NC, thereby enabling the development of effective control and mitigation strategies.
Highlights
By definition, PM2.5 represents particulate matter (PM) with aerodynamic equivalent diameter ≤ 2.5 μm
Hu et al (2014) used satellite-retrieved aerosol optical depth (AOD) data to estimate the spatiotemporal variations of PM2.5 mass concentrations in the southeastern U.S in 2001–2010; the results indicated that urban areas and major highways can display higher PM2.5 concentrations than rural or mountain areas
Goetz et al (2008) analyzed the major compositions of PM2.5 in eastern North Carolina (NC) from 2001 to 2004 at sites representing urban and rural sites; the results indicated that organic carbon (OC), SO42, ammonium (NH4+), NO3– and elemental carbon (EC) were the major contributors to PM2.5 mass; SO42– and NH4+ tended to be slightly higher in the rural site
Summary
PM2.5 represents particulate matter (PM) with aerodynamic equivalent diameter ≤ 2.5 μm. Hu et al (2014) used satellite-retrieved aerosol optical depth (AOD) data to estimate the spatiotemporal variations of PM2.5 mass concentrations in the southeastern U.S in 2001–2010; the results indicated that urban areas and major highways can display higher PM2.5 concentrations than rural or mountain areas. Around 20% reduction in PM2.5 concentrations has been achieved over the past 10 years in the southeastern U.S Previous research on the spatiotemporal variations of PM2.5 mass and chemical compositions in the U.S has indicated that PM2.5 mass concentrations had higher values in the eastern U.S and California and lower values in the central and northwestern regions of the nation. Previous research has discovered that different areas exhibited different PM2.5 chemical characteristics such that the regional impact of PM2.5 may differ correspondingly
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
