Observation Studies on Atmospheric Pollutants in Hangzhou. Yu Zhou

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1 Observation Studies on Atmospheric Pollutants in Hangzhou Yu Zhou

2 Outline Conclusions Site description Results Background

3 研究背景及意 绪论 Background In pace with fast development of urbanization and modernization, the rapid growth of urban people, the irrational pattern in the industry and the irrational energy structure make the air pollution becomes increasingly serious. A series of air pollution episodes occurred one after anther in many cities in China since 2013 which drew great attention of people and scientists. Some existing studies on atmospheric pollutants in Hangzhou are not very thorough and not very comprehensive enough, so it is very necessary to take long-term observation and studies on atmospheric pollutants in Hangzhou.

4 Site description 5km 研究意义 The monitoring station is located in a flat land where there are 理论基础与文献综述 few tall buildings and local source.

5 Data screening a The effective hourly mean value is the mathematic average of at least 75% of effective values of one hour. 研究意义 b The effective daily mean value is the mathematic average of at least 18 effective hourly mean values of one day. c The effective monthly mean value is the mathematic average of at least 21 effective daily mean values of one month. d The effective annual mean value is the mathematic average of total of 12 effective monthly mean values of one year. 理论基础与文献综述

6 Results Table 1 Exceeding standard rates of some atmospheric pollutants in 2014 Items O 3 NO 2 SO 2 CO PM 2.5 PM 10 Average time Exceeding Exceeding Total standard times standard rates/% Daily peak 8 hours average Hourly average Annual average Daily average Hourly average Annual average Daily average Hourly average Daily average Hourly average Annual average Daily average Annual average Daily average

7 Fig. 1 Concentration variation of O 3, O x, O 3-8hmax, NO 2, SO 2, CO, PM 2.5 and PM 10 in 2014

8 Table 2 Seasonal concentrations of some atmospheric pollutants in 2014/μg m -3 Items Spring Summer Autumn Winter Annual mean O ± ± ± ± ±47.1 O x 108.7± ± ± ± ±40.6 NO ± ± ± ± ±22.1 SO ± ± ± ± ±13.8 CO(mg m -3 ) 0.85± ± ± ± ±0.31 PM ± ± ± ± ±38.6 PM ± ± ± ± ±54.8

9 Fig. 2 Daily variation of O 3, O x, NO 2, SO 2, CO, PM 2.5 and PM 10 during different seasons in 2014

10 Daily average Table 3 Weekly concentrations of NO 2 and O 3 in 2014/μg m -3 Days of week Extremums Mon Tues Wed Thurs Fri Sat Sun Maximum Maximum NO (Sun) 53.3(Thurs) O (Sun) 56.1(Thurs) Daily peak NO (Sun) 81.3(Thurs) O (Sun) 121.2(Thurs)

11 65 60 工作日 周末 NO 2 / g m O 3 / g m 北京时间 Fig. 3 Daily variation of NO 2 and O 3 in weekdays and on weekends in 2014

12 Table 4 Exceeding standard rates of some atmospheric pollutants during winter from 2012 to 2014 Items Average time Exceeding standard rates/% Daily average NO 2 SO 2 CO PM 2.5 PM 10 Hourly average Seasonal average /μg m Daily average Hourly average Seasonal average /μg m Daily average Hourly average Seasonal average /μg m Daily average Seasonal average /μg m Daily average Seasonal average /μg m Increase first and then decrease

13 Fig. 4 Distribution characteristics of SO 2, NO 2, PM 10 and PM 2.5 during winter from 2012 to 2014

14 Fig. 5 Regional distribution of some atmospheric pollutants in 2014

15 Table 5 Correlation coefficients between pollutants and meteorological parameters based on hourly mean data during different seasons in 2014 Seasons Spring Summer Autumn Winter meteorological elements air temperature wind speed relative humidity air temperature wind speed relative humidity air temperature wind speed relative humidity air temperature wind speed relative humidity NO 2 O 3 SO 2 CO PM 2.5 PM ** 0.59 ** ** ** 0.33 ** ** 0.36 ** ** ** ** ** 0.17 ** ** ** 0.32 ** 0.06 * ** ** 0.65 ** 0.06 * ** 0.10 ** 0.21 ** ** 0.26 ** ** ** ** ** 0.37 ** ** ** ** ** ** ** 0.60 ** ** ** ** ** ** 0.31 ** ** ** ** ** 0.11 ** ** ** 0.27 ** ** 0.07 * 0.41 ** 0.08 ** ** 0.22 ** ** 0.40 ** ** ** ** ** ** ** ** 0.15 ** **

16 Fig.6 Correlation coefficients between pollutants and meteorological parameters in 2014

17 WNW W NW NNW N 风速 /m S -1 NNE NE ENE E WNW W NW NNW N 风向频率 /% NNE NE ENE E WSW ESE WSW ESE SW SE SW SE WNW W NW SSW NNW S C SSE NO 2 /ug m -3 N NNE NE ENE WNW W NW SSW NNW S C SSE O 3 /ug m -3 N NNE NE ENE lower WSW E WSW E SW ESE SW ESE SSW S SSE SE SSW S SSE SE Fig.7 Relationship between the atmospheric pollutants and wind directions during different seasons in 2014

18 WNW W NW NNW C SO 2 /ug m -3 N NNE NE ENE WNW W NW NNW C CO/mg m -3 N NNE NE ENE WSW E WSW E SW ESE SW ESE SSW NNW NW WNW W WSW SW S C SSE SE PM 2.5 /ug m -3 N NNE NE ENE E ESE higher WNW W WSW SW SSW NNW NW S C SE SSE PM 10 /ug m -3 N NNE NE ENE E ESE 春季夏季秋季冬季 SSW S SSE SE Fig.7 Relationship between the atmospheric pollutants and wind directions during different seasons in 2014 SSW S SSE SE

19 Conclusions Of the atmospheric pollutants, PM 2.5 was the most serious in the urban area of Hangzhou. The concentrations of the atmospheric pollutants displayed noticeable seasonal variation. The concentrations of O 3 from highest to lowest were in summer, autumn, spring and winter, while the others appeared higher in winter, lower in summer and changed smoothly in other seasons. The concentrations of the atmospheric pollutants showed different diurnal variation patterns. The curves of diurnal variations of O 3, Ox and SO 2 all showed single peak with different peak values time. The diurnal variations of NO 2, CO, PM 2.5 and PM 10 were similar to the two peaks that appeared at the morning and evening rush hours.

20 The concentrations of NO 2 from 17:00 to 09:00 the next morning in weekdays were significantly higher than those on weekends. The situation from 09:00 to 14:00 was the opposite and the concentrations from 14:00 to 17:00 approximately equaled. But the concentrations of O 3 in weekdays were higher than those on weekends all the time. The exceeding standard rate of daily average concentrations and annual average concentrations of NO 2, PM 2.5 and PM 10 of the winters of the last three years increased second year and then decreases from 2012 to 2014, while annual average concentrations of SO 2,and CO increased all the time. On the whole, the concentrations of the pollutants were decreased from the east to the west of Hangzhou gradually. There were 3 high-value regions of concentration of CO.

21 Meteorological factors were an important factor for pollutant concentration distributions. The correlation analysis indicated that the concentration of O 3 was the most significant positively correlations with temperature and wind speed, while the most significant negatively correlations with relative humidity. The situation with NO 2 was the opposite. The concentrations of SO 2, CO, PM 2.5 and PM 10 were the most significant negatively correlations with wind speed.

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