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| Pollution characteristics of PM2.5 and gaseous pollutants in winter and spring at agricultural region of Hailun city, Heilongjiang Province |
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Abstract To know the pollution levels, possible emission sources and transport process in agricultural region, on-line measurements of main air pollutants (i.e., PM2.5, NOx, O3 and SO2) were conducted from November 1 2011 to April 30 2012 at National Observation Station of Hailun Agro-ecology System, Heilongjiang Province and further analysis were taken with surface meteorology data and backward trajectories model (i.e., HYSPLIT). The average of daily concentrations of PM2.5, NOx, and SO2 during the measurement period were (54.7±45.7) (8.0~217.8)、(23.0±11.5) (4.5~59.6) and (10.0±10.3) (0.3~56.0) μg/m3, respectively. The maximum average 8hours of O3 concentration was (62.4±18.7) (24.1~173.5) μg/m3. The gaseous pollutant levels were all below the National Ambient Air Quality Standard (NAAQS) except O3. Daily average of PM2.5 concentrations exceeded more than 40days as compared to NAAQS, which accounted for approximately one-fourth of measurement days. The concentrations of PM2.5 and SO2 were significantly higher in December than other months due to the greatest needs of winter heating. The diurnal variations of NOx, PM2.5 and SO2 were similar with two peaks occurring at 07:00and 17:00, while O3has one peak between 13:00to 15:00local time. The analysis of meteorology data and HYSPLIT suggested that the atmospheric pollution in winter is closely linked to local source emission, regional transport as well as the local meteorological conditions in Hailun city. South flows easily formed air pollution, while north wind favored the removal of pollutants by diffusion.
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Received: 26 July 2013
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