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Spatial and Temporal Variations of PM 2.5 and Its Relation to Meteorological Factors in the Urban Area of Nanjing, China

View Article: PubMed Central - PubMed

ABSTRACT

The serious air pollution problem has aroused widespread public concerns in China. Nanjing city, as one of the famous cities of China, is faced with the same situation. This research aims to investigate spatial and temporal distribution characteristics of fine particulate matter (PM2.5) and the influence of weather factors on PM2.5 in Nanjing using Spearman-Rank analysis and the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) method. Hourly PM2.5 observation data and daily meteorological data were collected from 1 April 2013 to 31 December 2015. The spatial distribution result shows that the Maigaoqiao site suffered the most serious pollution. Daily PM2.5 concentrations in Nanjing varied from 7.3 μg/m3 to 336.4 μg/m3. The highest concentration was found in winter and the lowest in summer. The diurnal variation of PM2.5 increased greatly from 6 to 10 a.m. and after 6 p.m., while the concentration exhibited few variations in summer. In addition, the concentration was slightly higher on weekends compared to weekdays. PM2.5 was found to exhibit a reversed relation with wind speed, relative humidity, and precipitation. Although temperature had a positive association with PM2.5 in most months, a negative correlation was observed during the whole period. Additionally, a high concentration was mainly brought with the wind with a southwest direction and several relevant factors are discussed to explain the difference of the impacts of diverse wind directions.

No MeSH data available.


Seasonal variation of PM2.5 concentrations for the past three years in Nanjing. The bar represents the concentration of PM2.5 and the line means standard deviation; (a) Spring; (b) Summer; (c) Autumn and (d) Winter.
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ijerph-13-00921-f003: Seasonal variation of PM2.5 concentrations for the past three years in Nanjing. The bar represents the concentration of PM2.5 and the line means standard deviation; (a) Spring; (b) Summer; (c) Autumn and (d) Winter.

Mentions: Seasonal variations of PM2.5 concentrations for all sites in Nanjing are shown in Figure 3, where April and May were only included in the spring and December was included in the winter in 2013. PM2.5 pollution in the winter was much more severe than other seasons, especially in 2013, with the average value of up to 158.5 μg/m3. Normally, it is followed by spring (63.1 μg/m3) and autumn (59.9 μg/m3). The finest air quality appeared in the summer and the concentration value in the summer of 2014 (64.8 μg/m3) was higher than in 2013 (44.7 μg/m3) and 2015 (38.8 μg/m3). It can be seen from the statistics of standard deviation that the pollution condition of PM2.5 was most turbulent in the winter of 2013, consistent with the above analysis. In addition, the concentration in 2015 was significantly lower than in 2013 or in 2014.


Spatial and Temporal Variations of PM 2.5 and Its Relation to Meteorological Factors in the Urban Area of Nanjing, China
Seasonal variation of PM2.5 concentrations for the past three years in Nanjing. The bar represents the concentration of PM2.5 and the line means standard deviation; (a) Spring; (b) Summer; (c) Autumn and (d) Winter.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036754&req=5

ijerph-13-00921-f003: Seasonal variation of PM2.5 concentrations for the past three years in Nanjing. The bar represents the concentration of PM2.5 and the line means standard deviation; (a) Spring; (b) Summer; (c) Autumn and (d) Winter.
Mentions: Seasonal variations of PM2.5 concentrations for all sites in Nanjing are shown in Figure 3, where April and May were only included in the spring and December was included in the winter in 2013. PM2.5 pollution in the winter was much more severe than other seasons, especially in 2013, with the average value of up to 158.5 μg/m3. Normally, it is followed by spring (63.1 μg/m3) and autumn (59.9 μg/m3). The finest air quality appeared in the summer and the concentration value in the summer of 2014 (64.8 μg/m3) was higher than in 2013 (44.7 μg/m3) and 2015 (38.8 μg/m3). It can be seen from the statistics of standard deviation that the pollution condition of PM2.5 was most turbulent in the winter of 2013, consistent with the above analysis. In addition, the concentration in 2015 was significantly lower than in 2013 or in 2014.

View Article: PubMed Central - PubMed

ABSTRACT

The serious air pollution problem has aroused widespread public concerns in China. Nanjing city, as one of the famous cities of China, is faced with the same situation. This research aims to investigate spatial and temporal distribution characteristics of fine particulate matter (PM2.5) and the influence of weather factors on PM2.5 in Nanjing using Spearman-Rank analysis and the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) method. Hourly PM2.5 observation data and daily meteorological data were collected from 1 April 2013 to 31 December 2015. The spatial distribution result shows that the Maigaoqiao site suffered the most serious pollution. Daily PM2.5 concentrations in Nanjing varied from 7.3 μg/m3 to 336.4 μg/m3. The highest concentration was found in winter and the lowest in summer. The diurnal variation of PM2.5 increased greatly from 6 to 10 a.m. and after 6 p.m., while the concentration exhibited few variations in summer. In addition, the concentration was slightly higher on weekends compared to weekdays. PM2.5 was found to exhibit a reversed relation with wind speed, relative humidity, and precipitation. Although temperature had a positive association with PM2.5 in most months, a negative correlation was observed during the whole period. Additionally, a high concentration was mainly brought with the wind with a southwest direction and several relevant factors are discussed to explain the difference of the impacts of diverse wind directions.

No MeSH data available.