香港大气能见度与污染物长期变化的特征和相互关系

利用香港天文台40年(1968~2007年)的能见度数据,中西区空气监测站24年(1984~2007年)的空气质量数据,采用多元回归法,分析了香港地区大气环境状况与大气污染物变化的关系.结果表明,香港地区1968~2007年间低能见度时数百分比平均每10年上升3.1%,其中,其上升趋势在1968~1989年较为平缓(平均0.7%/10a),20世纪90年代后(1990~2007年)则较为明显(平均7.3%/10a),且与地面臭氧浓度呈同步上升趋势.1993年前,低能见度时数百分比与NO2和NOx相关性显著,1993年后,与其相关性显著的污染物则是O3、SO2和NO2.这说明香港地区能见度的恶化在1993年前与光化学烟雾有关,但在1993年后则同时受光化学烟雾和与硫酸盐粒子有关的气溶胶烟雾的共同影响.

Characterization and relationship of long-term visibility and air pollutant changes in the Hongkong region

40 years (1968~2007) visibility and 24 years (1984~2007) air quality monitoring data from Hongkong were analyzed to examine the relationship between atmospheric environmental degradation in terms of reduced visibility (RV) and air pollutant concentration change by multiple regression analysis method. The time with RV in Hongkong increased 3.1% during 1968~2007. The increase trend was mild during 1968~1989 (0.7% per decade), but being sharp from the 1990s (1990~2007, 7.3% per decade), simultaneously with increase in surface ozone concentration. Time with RV correlated well with NO2 and NOx before 1993, but with O3, SO2 and NO2 after 1993. The visibility degradation in Hongkong related to photochemical smog before 1993, but afterwards, it was also affected by aerosol smog associated with sulfate besides photochemical smog.