1981~2010年深圳市不同等级霾天气特征分析

利用1981~2010年深圳市地面观测及空气质量监测资料,分析深圳不同等级霾天气的长期变化特征以及大气水平能见度、空气质量与霾的关系.结果表明:深圳霾日数总体呈增多趋势,强度增强,中度以上霾增多;各等级霾日数均呈增多态势,但不同等级霾日占年总霾日的比例变化趋势不同,轻微霾所占比例下降,轻度以上霾上升; 霾天气呈现冬季>秋季>春季>夏季的季节特征,但重度霾却是夏季最多; 霾导致大气水平能见度明显下降,霾日平均能见度较非霾日低6~7km,霾等级越高,能见度下降越明显,霾日能见度日变化幅度较非霾日小;霾日SO2、NO2浓度为非霾日的1.4~1.7倍,PM10是非霾日的2.2倍,大气颗粒物污染加剧可能是深圳能见度恶化、霾天气增多的一个重要原因;针对荔香站霾日SO2浓度日变化不明显,PM10 、NO2浓度呈双峰型分布,与上下班时段吻合,说明机动车的增加也是深圳霾天气增多的主因之一;霾等级越高,空气中PM10、SO2、NO2的浓度越高,从轻微到重度霾各级之间SO2、NO2和PM10浓度增幅大都在15%~20%.

Characteristics of haze weathers with different level in Shenzhen during 1981~2010

Based on the observational haze data and the air environment quality data in Shenzhen during 1981~2010, the long-term variation tendency of the haze weather with different level was analyzed along with the relationship between the haze weather and the atmospheric visibility, air quality. The annual haze days of Shenzhen showed an increasing trend overall. At the same time, the numbers of the haze days at each level, such as slight, mild, moderate and severe, also showed an increasing trend. The proportion of the slight haze declined, while the proportion of the haze over the mild level rose over the 30 years. For different seasons, the maximum occurrence probability of haze weather was recorded in winter, followed by autumn, spring and summer sequentially. However, the severe level of haze happened mostly in summer. The occurrence of the haze weather often led to the descending of the atmospheric horizontal visibility that average visibility during haze days was about 6~7km lower than it in non-haze days, and a higher level of haze often result in a lower visibility. The air quality monitoring data suggested that the SO2, NO2 concentrations during haze days were 1.4~1.7 times of those in the non-haze days, while the PM10 concentration was 2.2 times, which indicated the increase of atmospheric particulate pollution was possibly one important reason of haze increasing. For Lixiang Station, PM10 and NO2 concentrations during haze days exhibited a bimodal diurnal variation characteristics which was accordant with the rush hours, which suggested that the increasing number of the motor vehicles contributed to haze weather in Shenzhen. The data also showed that the higher the haze level was, the higher of the PM10, SO2 and NO2 concentrations, and the increase of the PM10, SO2 and NO2 concentrations between each haze level was about 15%~20% .