Investigation of relationship between particulate matter (PM2.5) and meteorological parameters in Isfahan, Iran

Isfahan is one of the most important industrial cities in central Iran that air pollution has been the biggest challenge of this city in recent years.  So, the present study aimed to investigate the effect of meteorological parameter on particulate matter concentration (PM2.5) in ambient air of Isfahan metropolitan, from March 2019 to March 2020.

In this cross‑sectional descriptive study, 19 sampling points in Isfahan city were chosen using GIS software. Sampling of PM2.5 was carried out for 24 hour using the sampling pilot during the four seasons in the air of Isfahan city. Sampling of PM2.5 was performed using PTFE filters (37mm, 1µ) peripheral pump and Personal Modular Impactor (Based on NIOSH Guideline). The concentration of particles collected on the filter was calculated by gravimetric method. Meteorological parameters including temperature, humidity, pressure, Precipitation, UV and Wind speed were recorded during sampling through portable devices. Finally, for the processing of PM2.5, relationship between PM2.5 concentration and meteorological parameters was assessed by SPSS24 and EXCEL software, and to draw the graphs, Excel and R software were used, respectively. ArcGIS 10.3 was used for the spatial distribution of PM2.5 concentration. The inverse distance weighting (IDW) interpolation technique was applied to generate maps for annual averages.

Seasonal variation trends of PM2.5 particles showed that maximum and minimum annual mean concentrations has happened in Winter and Summer season with the value of 64.06 and 31.32 µg/m3, respectively. Also the citizens of Isfahan are exposed to PM2.5 pollutants 4-5 times more than the EPA-recommended standard (10 µg/m3). The findings of this study also show that there is a positive correlation between PM2.5 particle concentration and temperature, relative humidity and pressure (p<0.05). Moreover, a weak and negative correlation was found between ultraviolet radiation, Precipitation, and Wind speed with PM2.5 particle concentration (p>0.05).

The highest concentrations of particles were observed in winter season. Also, the particle concentration scatter map shows that the central and north and northeast regions of Isfahan are more polluted than other areas. Therefore, to protect the health of citizens of Isfahan, appropriate policies and strategies should be adopted to reduce the concentration of particulate matter and other pollutants in the ambient air of this city`.