科研成果

Carbonyl compounds play an important role in the formation of secondary aerosols and the cycling of free radicals in the atmosphere. We measured carbonyl compounds over urban Beijing, a megacity in the North China Plain, in summer and winter to investigate the relation of carbonyl compounds with haze and the interaction between carbonyl compounds and atmospheric radical cycling. We also determined carbonyl compounds in summer rainwater. Data of carbonyl compounds were analyzed in four cases, i.e., summer haze days (SHD), summer non-haze days (SND), winter haze days (WHD), and winter non-haze days (WND). Interestingly, the level of carbonyl compounds during WHD approached that of summer days. The results of the principal component analysis showed that there was no obvious source difference between SHD and SND. On WHD, however, more carbonyl compounds originated from the “diesel engine exhaust emission” than those on WND. We evaluated the effect of carbonyl compounds on the free radical cycling and the NO consumption potential for OH formation in the photochemical reactions using a novel ratio method. It was found that the production rate of ROx (the sum of OH, HO2 and RO2 radicals) was highest on SND, while the yield of ROx radicals from the reactions of carbonyl compounds was highest on WHD. Further, carbonyl compounds consumed more NO to produce OH radicals on WHD compared to the other three cases.

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.

A comprehensive measurement was conducted to investigate thecharacteristics of particulate matter (PM) pollution in winter and spring of Beijing. 24-hour particle samples were collected from December to May, 20092010, and the chemical compositions of PM2.5 were analyzed. The average PM2.5 massconcentrations were (84.97+or-68.98)mug/m3 and (65.25+or-45.76) mug/m3 in winter and spring, respectively. Secondary inorganic aerosols, i.e. sulfate, nitrate, andammonium (SNA), and secondary organic aerosols (SOA) were dominant theparticulate matter, with the total fraction (SNA+SOA) of 49% and 47% in winter and spring, respectively. Due to the largesource emissionand unfavorable meteorological conditions such as low temperature, low wind speed, and high relative humidity; the contributions of secondary inorganic aerosols (NH4+. NO3. SO42) were enhanced during thepolluted days, and the nitratewas more enhanced on polluted days. The SOA was always the most importantorganic aerosolcomponentcontributedto PM2.5 in winter and spring. The contribution ofprimary organicaerosolsalso increased due tothe stagnant meteorological condition on polluted days.

China's commitment to the UNFCCC to peak its emissions by 2030, or sooner, signaled a long anticipated shift in China's model of development with far reaching consequences. Cities in China, and particularly the residential sector in cities, will be charged with making significant reductions in emissions growth even as rates of urbanization continue to climb. Focusing on Beijing and Shanghai, this paper carries out a measures-based economic analysis of low carbon investment opportunities in the residential sector. Results find significant opportunity: between 2015 and 2030, BAU levels of CO2 emissions could be reduced by 10.2% in Beijing and 6.8% in Shanghai with the adoption of economically attractive low carbon measures. While these headline results underline the case for low carbon investment in the residential sectors of these megacities in China, a closer analysis provides insights for understanding the economics of decarbonisation in cities more generally. (C) 2016 The Authors. Published by Elsevier Ltd.