Impact of introducing net-zero carbon strategies on tropospheric ozone (O3) and fine particulate matter (PM2.5) concentrations in Japanese region in 2050.

In this study, we estimated the future emission inventory of primary air pollutants in Japan in 2050 after introducing low-carbon technology based on the results of the socio-economic model provided by the Japanese government. The results suggested that introducing net-zero carbon technology would contribute to a 50-60 % decrease in primary NOx, SO2, and CO emissions and a ~30 % decrease in primary emissions of volatile organic compounds (VOCs) and PM2.5. The estimated emission inventory and future meteorological conditions in 2050 were applied as inputs to a chemical transport model. A scenario involving the application of future reduction strategies with relatively moderate global warming (RCP4.5) was evaluated. The results showed that the concentration of tropospheric ozone (O3) was highly reduced compared with that in 2015 after applying net-zero carbon reduction strategies. On the other hand, the fine particulate matter (PM2.5) concentration under the 2050 scenario was expected to be equal or higher because of the growth in secondary aerosol formation caused by the increase in short-wave radiation. Finally, the premature mortality change from 2015 to 2050 was analyzed, and the change in air quality contributed by net-zero carbon technology will contribute to a ~4000 decrease in premature deaths in Japan.

Loss of disability-adjusted life years due to heat-related sleep disturbance in the Japanese.

The purpose of this study was to quantify the sleep disturbances caused by climate change using disability-adjusted life years (DALY). The revised sleep quality index for daily sleep (SQIDS2), a self-administered questionnaire for daily sleep quality, was developed to assess daily sleep disturbances. This questionnaire referenced and simplified the Pittsburgh Sleep Quality Index (PSQI). This study was conducted in Nagoya City in August 2011 and 2012. Sleep quality was measured using SQIDS2 and PSQI. A total of 574 participants in 2011 and 710 in 2012 responded to the survey. The sleep disturbance prevalence calculated from the SQIDS2 score was correlated with the daily minimum temperature (p = 0.0067). This score increased when the daily minimum temperature was above 24.8 °C. When correcting for the PSQI score, DALY loss due to heat-related sleep disturbances in Nagoya City (population: 2,266,851) was estimated to be 81.8 years in 2012. This value was comparable to the DALY loss due to heatstroke. Sleep disturbance due to climate change was quantified using the DALY based on the PSQI. Legislators must recognize the critical impact of the damage caused by sleep disturbances due to high temperatures at night. Additionally, a daily minimum temperature of 25 °C should be the starting point when establishing a goal or guideline for nighttime temperature.

The right place for the right job in the photovoltaic life cycle.

The potential for photovoltaic power generation (PV) to reduce primary energy consumption (PEC) and CO(2) emissions depends on the physical locations of each stage of its life cycle. When stages are optimally located, CO(2) emissions are reduced nearly ten times as much as when each stage is located in the country having the largest current market share. The usage stage contributes the most to reducing CO(2) emissions and PEC, and total CO(2) emissions actually increase when PV is installed in countries having small CO(2) emissions from electricity generation. Global maps of CO(2) reduction potential indicate that Botswana and Gobi in Mongolia are the optimal locations to install PV due to favorable conditions for PV power generation and high CO(2) emissions from current electricity generation. However, the small electricity demand in those countries limits the contribution to global CO(2) reduction. The type of PVs has a small but significant effect on life cycle PEC and CO(2) emissions.

Effect of temperature on PV potential in the world.

This work aims to identify the geographic distribution of photovoltaic (PV) energy potential considering the effect of temperature on PV system performance. A simple framework is developed that uses the JIS C 8907 Japanese industrial standard to evaluate the effects of irradiation and temperature on PV potential. The global distributions of PV potential and yearly performance ratio are obtained by this framework. Generally, the performance ratio decreases with latitude because of temperature. However, regions with high altitude have higher performance ratios due to low temperature. The southern Andes, the Himalaya region, and Antarctica have the largest PV potentials. Although PV modules with less sensitivity to temperature are preferable for the high temperature regions, PV modules that are more responsive to temperature may be more effective in the low temperature regions. The correlation between the estimates obtained by our framework and results from a more data-intensive method increases when the temperature effects are considered.

Life cycle assessment of integrated municipal solid waste management systems, taking account of climate change and landfill shortage trade-off problems.

Steps taken to counter the climate change problem have a significant impact on the municipal solid waste management (MSW) sector, which must tackle regional environmental problems such as the shortage of sanitary landfills, especially in Japan. Moreover, greenhouse gas emissions and final disposal have a trade-off relationship. Therefore, alleviation of both these environmental problems is difficult, and Japanese local municipalities are anxious for action to solve these problems and reduce treatment costs. Although ambitious waste management measures have been enacted in many countries, they appear to lack a holistic view and do not adopt a life cycle approach. Therefore, it is important to reconstruct the MSW management system, taking into account environmental and economic aspects. In the present study, life cycle assessment and mathematical modelling were used to seek ways of redesigning the MSW management system in order to minimize environmental impacts and/or reduce treatment costs. One economic block was selected as the study area (Iwate Prefecture in Japan). The life cycle inventory and costs data for every MSW transportation and treatment process in this region were collected and processed. Then, taking account of geographic information, an optimal solution for the minimization of environmental impact or treatment costs was derived. To solve the trade-off problem, a sensitivity analysis was conducted to find optimal reduction targets for climate change and final disposal.