Search

Jakarta Greater Area (JGA) has encountered recurrent challenges of air pollution, notably, high ozone levels. We investigate the trends of surface ozone (O3) changes from the air quality monitoring stations and resolve the contribution of meteorological drivers in urban Jakarta (2010–2019) and rural Bogor sites (2017–2019) using stepwise Multi Linear Regression. During 10 years of measurement, 41% of 1-h O3 concentrations exceeded Indonesia' s national threshold in Jakarta. In Bogor, 0.1% surpassed the threshold during 3 years of available data records. The monthly average of maximum daily 8-h average (MDA8) O3 anomalies exhibited a downward trend at Jakarta sites while increasing at the rural site of Bogor. Meteorological and anthropogenic drivers contribute 30% and 70%, respectively, to the interannual O3 anomalies in Jakarta. Ozone formation sensitivity with satellite demonstrates that a slight decrease in NO2 and an increase in HCHO contributed to declining O3 in Jakarta with 10 years average of HCHO to NO2 ratio (FNR) of 3.7. Conversely, O3 increases in rural areas with a higher FNR of 4.4, likely due to the contribution from the natural emission of O3 precursors and the influence of meteorological factors that magnify the concentration. [ABSTRACT FROM AUTHOR]

Despite ozone precursor emission reduction efforts in most polluted areas worldwide, photochemical ozone remains among the most concerning air pollutants in some regions, possibly because of spatial heterogeneity of ozone sensitivity to individual precursors. However, regional differences in ozone sensitivity to volatile organic compounds (VOCs), a major precursor, have not been quantitatively shown. Therefore, this study estimated the spatial variations in the efficacy of VOC emission reductions to mitigate photochemical ozone concentrations and population exposure (as related to ozone-related health problems) over Japan, and to inform policy makers pursuing effective ozone reduction strategies in polluted regions. Using air quality simulations, we found that the abovementioned efficacy differed substantially, up to 10-fold, among 20 × 20-km areas in which VOCs had been reduced. Using the above-calculated spatial distribution of the efficacy and data on emission source locations of several industries, upstream industries (e.g., petroleum and coal products) showed greater reduction efficacies than downstream industries (e.g., plastic products). By comparing the calculated ozone sensitivity to VOCs with the ozone–NOx–VOC sensitivity derived from space-based observations of the HCHO/NO2 column ratio from the Ozone Monitoring Instrument, the general spatial trends in ozone sensitivity to VOC emission reductions were verified qualitatively. Thus, regional countermeasures should be considered rather than the existing uniform nationwide measures in Japan. Moreover, to prioritize VOC emission reductions by industry, considering the reactivity or ozone formation potential of each emitted VOC exclusively, as is currently done, is insufficient, the emission locations of each industry should also be considered. [ABSTRACT FROM AUTHOR]

A sensor for the detection of ethylene (CH) in combustion exhaust based on a mid-infrared wavelength modulation spectroscopic technique was constructed using a distributed feedback interband cascade laser (DFB-ICL) with a wavelength of 3.3 μm. The direct absorption spectrum of CH in the range of 2978.8-2982.1 cm was recorded, where the spectrum was in good agreement with the spectrum simulated using parameters from the HITRAN 2012 database. The absorption line at 2979.581 cm [2.42 × 10 cm mol cm, ν P(5)] was selected for CH detection. This frequency was chosen to minimize spectral interference from other major combustion products in the emission frequency range of the DFB-ICL. A limit of detection for CH of 96 parts per billion by volume was achieved at a signal-to-noise ratio of two under 3 kPa of pressure using 2 f wavelength modulation spectroscopy. Using the developed sensor, the ethylene concentration in the exhaust from a portable power generator was also successfully determined. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

The plans to introduce next-generation hybrid and zero-emission vehicles in the market are now enacted by governments in many countries to manage both global warming and air pollution problems. There are only a few studies evaluating the effects of the next-generation vehicles on the changes in concentrations of ozone generated by the photochemical reactions between volatile organic compounds and nitrogen oxides (NOx). To evaluate these changes, we performed chemical transport modeling in the Kanto region, Japan in the summer of 2013. The results show that if the vehicles are substituted by hybrid vehicles, average ozone concentrations increase in urban areas and decrease in suburban areas due to NOx titration. Substitution with zero-emission passenger vehicles decreases the concentrations in both urban and suburban areas. Substitution with both hybrid and zero-emission passenger and heavy-duty vehicles highly increases the concentrations in urban areas. Using the model results, we also discuss the effect of ozone concentration changes on premature mortality of humans in summer. The results suggest that, in some cases the introduction of next-generation vehicles might exasperate ozone concentrations, even leading to 5 to 10 times higher premature mortality during the summer compared to that of influenza and heat stroke in Japan. [ABSTRACT FROM AUTHOR]