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Abstract. Mixing ratios of volatile organic compounds (VOCs) were recordedin two field campaigns in central Beijing as part of the Air Pollution andHuman Health in a Chinese Megacity (APHH) project. These data were used tocalculate, for the first time in Beijing, the surface–atmosphere fluxes ofVOCs using eddy covariance, giving a top-down estimation of VOC emissionsfrom a central area of the city. The results were then used to evaluate theaccuracy of the Multi-resolution Emission Inventory for China (MEIC). TheAPHH winter and summer campaigns took place in November and December 2016and May and June 2017, respectively. The largest VOC fluxes observed were ofsmall oxygenated compounds such as methanol, ethanol + formic acid andacetaldehyde, with average emission rates of 8.31 ± 8.5, 3.97 ± 3.9 and 1.83 ± 2.0 nmol m−2 s−1, respectively, in the summer.A large flux of isoprene was observed in the summer, with an average emissionrate of 5.31 ± 7.7 nmol m−2 s−1. While oxygenated VOCs madeup 60 % of the molar VOC flux measured, when fluxes were scaled by ozoneformation potential and peroxyacyl nitrate (PAN) formation potential thehigh reactivity of isoprene and monoterpenes meant that these speciesrepresented 30 % and 28 % of the flux contribution to ozone and PANformation potential, respectively. Comparison of measured fluxes with theemission inventory showed that the inventory failed to capture the magnitudeof VOC emissions at the local scale. 

One of the environmental crises facing the world is pollution due to rubber auto tire destruction. The use of tires in vehicles consumes 6% of the world's energy and causes 5% of carbon dioxide emissions; it accounts for up to 10% of the microplastic pollution found in oceans. Here, a new rubber nanocomposite self‐assembled from hard and soft elastomer matrixes is designed: polybutadiene with its two hydroxy chain ends reacts with 4,4'‐diphenylmethane diisocyanate to form segmented polyurethane. This system first undergoes self‐assembly, forming well‐defined nanoscale hard domains distributed in the soft matrix. Then, cross‐linking between the soft segments is accomplished by a controlled radiation method, resulting in the double network elastomer (DN‐E). Remarkably, the DN‐E exhibits the lowest reported loss factor value at 60 °C. The index of energy dissipation in the rolling tire demonstrates a prominent reduction of 72%, accomplished with an 88% decrease in energy loss, and 85% less wear loss, as compared with best earlier reported commercial tires. These new double‐network materials open a new prospective for the design and fabrication of ultralow energy‐consumption and strong abrasion‐resistance elastomers, which establishes a milestone for the development of the next generation of green low‐pollution tires causing much less energy dissipation.