<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Y.N. Xing</style></author><author><style face="normal" font="default" size="100%">H. Li</style></author><author><style face="normal" font="default" size="100%">L.B. Huang</style></author><author><style face="normal" font="default" size="100%">H.H. Wu</style></author><author><style face="normal" font="default" size="100%">H.Q. Shen</style></author><author><style face="normal" font="default" size="100%">Chen, Z. M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The production of formaldehyde and hydroxyacetone in methacrolein photooxidation: New insights into mechanism and effects of water vapor</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Environmental Sciences</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2018</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.sciencedirect.com/science/article/pii/S1001074217306101</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">66</style></volume><pages><style face="normal" font="default" size="100%">1-11</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Methacrolein (MACR) is an abundant multifunctional carbonyl compound with high&lt;br&gt;reactivity in the atmosphere. In this study, we investigated the hydroxyl radical initiated&lt;br&gt;oxidation of MACR at various NO/MACR ratios (0 to 4.04) and relative humidities (&amp;lt; 3% to&lt;br&gt;80%) using a flow tube. Meanwhile, a box model based on the Master Chemical Mechanism&lt;br&gt;was performed to test our current understanding of the mechanism. In contrast to the&lt;br&gt;reasonable predictions for hydroxyacetone production, the modeled yields of formaldehyde&lt;br&gt;(HCHO) were twice higher than the experimental results. The discrepancy was ascribed to&lt;br&gt;the existence of unconsidered non-HCHO forming channels in the chemistry of CH&lt;sub&gt;3&lt;/sub&gt;C(=CH&lt;sub&gt;2&lt;/sub&gt;)OO&lt;sup&gt;.&lt;/sup&gt;, which account for approx. 50%. In addition, the production of hydroxyacetone&lt;br&gt;and HCHO were affected by water vapor as well as the initial NO/MACR ratio. The yields of&lt;br&gt;HCHO were higher under humid conditions than that under dry condition. The yields of&lt;br&gt;hydroxyacetone were higher under humid conditions at low-NO&lt;sub&gt;x&lt;/sub&gt; level, while lower at&lt;br&gt;high-NO&lt;sub&gt;x&lt;/sub&gt; level. The reasonable explanation for the lower hydroxyacetone yield under&lt;br&gt;humid conditions at high-NO&lt;sub&gt;x&lt;/sub&gt; level is that water vapor promotes the production of&lt;br&gt;methacrolein nitrate in the reaction of HOCH&lt;sub&gt;2&lt;/sub&gt;C(CH&lt;sub&gt;3&lt;/sub&gt;)(OO&lt;sup&gt;.&lt;/sup&gt;)CHO with NO due to the peroxy&lt;br&gt;radical-water complex formation, which was evidenced by calculational results. And the&lt;br&gt;minimum equilibrium constant of this water complex formation was estimated to be&lt;br&gt;1.89 × 10&lt;sup&gt;−18&lt;/sup&gt; cm&lt;sup&gt;3&lt;/sup&gt;/molecule. These results provide new insights into the MACR oxidation&lt;br&gt;mechanismand the effects of water vapor.&lt;/p&gt;</style></abstract></record></records></xml>