Quantitative impacts of meteorology and precursor emission changes on the long-term trend of ambient ozone over the Pearl River Delta, China, and implications for ozone control strategy

China is experiencing increasingly serious ambient ozone pollution, including the economically developed Pearl River Delta (PRD) region. However, the underlying reasons for the ozone increase remain largely unclear, leading to perplexity regarding formulating effective ozone control strategies. In this study, we quantitatively examine the impacts of meteorology and precursor emissions from within and outside of the PRD on the evolution of ozone during the past decade by developing a statistical analysis framework combining meteorological adjustment and source apportionment. We found that meteorological conditions mitigated ozone increase, and that their variation can account for a maximum of 15 % of the annual ozone concentration in the PRD. Precursor emissions from outside the PRD (“nonlocal”) have the largest contribution to ambient ozone in the region and show a consistently increasing trend, whereas emissions from within the PRD (“local”) show a significant spatial heterogeneity and play a more important role during ozone episodes over the southwest of the region. Under general conditions, the impact on the northeastern PRD is positive but decreasing, and in the southwest it is negative but increasing. During ozone episodes, the impact on the northeastern PRD is negative and decreasing, whereas in the southwestern PRD it is positive but decreasing. The central and western PRD are the only areas with an increasing local ozone contribution. The spatial heterogeneity in both the local ozone contribution and its trend under general conditions and during ozone episodes is well interpreted by a conceptual diagram that collectively takes ozone precursor emissions and their changing trends, ozone formation regimes, and the monsoonal and microscale synoptic conditions over different subregions of the PRD into consideration. In particular, we conclude that an inappropriate NOx∕VOC control ratio within the PRD over the past few years is most likely responsible for the ozone increase over southwest of this region, both under general conditions and during ozone episodes. By investigating the ozone evolution influenced by emission changes within and outside of the PRD during the past decade, this study highlights the importance of establishing a dichotomous ozone control strategy to tackle general conditions and pollution events separately. NOx emission control should be further strengthened to alleviate the peak ozone level during episodes. Detailed investigation is needed to retrieve appropriate NOx∕VOC ratios for different emission and meteorological conditions, so as to maximize the ozone reduction efficiency in the PRD.

Quantitative impacts of meteorology and precursor emission changes on the long-term trend of ambient ozone over the Pearl River Delta, China and implications for ozone control strategy

China is experiencing increasingly serious ambient ozone pollution, including the economically developed Pearl River Delta (PRD) region. However, the underlying reasons for ozone increase remain largely unclear, leading to perplexity in formulating effective ozone control strategies. In this study, by developing a statistical analysis framework combining meteorological adjustment and source apportionment, we examine quantitatively the impacts of meteorology and precursor emissions from within and outside the PRD on the evolution of ozone during the past decade. We found that meteorological condition has mitigated ozone increase, and its variation can account for at most 15 % of annual ozone concentration in the PRD. Precursor emission from outside the PRD (non-local) makes the largest contribution to ambient ozone in the PRD and shows a consistently increasing trend, while that from within the PRD (local) shows a significant spatial heterogeneity and plays a more important role during ozone episodes over southwestern. Under general conditions, the impact on northeastern is positive but decreasing, and on southwestern is negative but increasing. During ozone episodes, the impact on northeastern is negative and decreasing, while on southwestern is positive but decreasing. Central and western PRD is the only area with increasing local ozone contribution. The spatial heterogeneity in both local ozone contribution and its trend under general conditions and ozone episodes are well interpreted by a conceptual model collectively taking into account ozone precursor emissions and their changing trends, ozone formation regimes, and the monsoonal and micro-scale synoptic conditions over different sub-regions of the PRD. In particular, we conclude that the inappropriate NOx / VOC control ratio within the PRD over the past years is most likely responsible for the ozone increase over southwestern, both under general conditions and during ozone episodes. By investigating the ozone evolution influenced by emission changes within and outside PRD during the past decade, this study highlights the importance of establishing a dichotomous ozone control strategy to tackle with general conditions and pollution events separately. NOx emission control should be further strengthened to alleviate peak ozone level during episodes. Detailed investigation is needed to retrieve appropriate NOx / VOC ratios for different emission and meteorological conditions, so as to maximize the ozone reduction efficiency in the PRD.

DESAIN GENERATOR OZONE DENGAN TEKNOLOGI PLASMA DBD (Die-lectric Barrier Discharge)

<p class="Abstract">Industrial sterilization is a very important problem. Ozone is a powerful oxidizer that can function for sterilization and is environmentally friendly. Plasma DBD (Dielectric Barrier Discharge) is one of the effective technologies to obtain ozone. The ozone generator currently uses a lot of manual control operations. Manual control uses a mechanical system in the form of a potentiometer to calibrate the frequency and output of the ozone generator output, so that digitization and automation are needed to operate to replace human labor. The design of the digital ozone control generator is done using an AVR microcontroller. Programming used in this research is basic language (BASCOM), then uses a DAC (Digital to Analog Converter) system which is the output of a Microcontroller with a Weighted Binnary Resistor. The output of the microcontroller is frequency and 8 bit digital with a decimal parameter of 200. The result of automation is that the timer works for 2 hours. The greater frequency the ozone produced. At a frequency of 1500Hz the power produced is 308.58 watts with an ozone concentration of 59 ppm. Efficiency using a switching system&gt; 90%.</p><p> </p><p class="IndexTerms"><strong>Keywords</strong>: Plasma, AVR Microcontroller, Ozone.</p>