The changes in different ozone metrics and their implications following precursor reductions over northern Taiwan from 1994 to 2007.
The changes of different O(3) metrics such as O(3_avg) (daily mean), O(X) (NO(2) + O(3)), O(3_8h) (daily maximum 8-h moving average), O(3_max) (daily maximum 1-h average), and exceedances of O(3_8h) and O(3_max) at 16 air quality monitoring stations over northern Taiwan from 1994 to 2007 are evaluated. The O(3_avg) at the background site displays an increasing trend at 0.54 +/-0.21 ppb (1.28 +/-0.49%) per year. The O(X) at urban sites shows a significant increase, indicating that even with the effect of reduced NO titration increasing photochemical production is evident. The exceedances of O(3_8h) (>80 ppb) are about 14.9% higher than O(3_max) (>120 ppb) with more exceedances at coastal or background sites, where the anthropogenic O(3) precursor emissions are lower. In addition to increasing background O(3) and reductions in NO titration, increasing O(3) production efficiency also plays a key role in the increase of moderate to high O(3) concentrations. The findings help explain the different trends in exceedances and levels of O(3_8h) and O(3_max) and are likewise important in the formation of O(3) control strategies.
Lin
Yu-Kai
YK
Environmental Protection Administration, Taipei, Taiwan, Republic of China.
Lin
Ta-Hsiung
TH
Chang
Shuenn-Chin
SC
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D009569:Nitric Oxide / Q000032:analysis; D010126:Ozone / Q000032:analysis*; D012621:Seasons; D013624:Taiwan
D000393:Air Pollutants; D009569:Nitric Oxide; D010126:Ozone