Instituto de Química, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Environ Monit Assess. 2020 Feb 1;192(3):156. doi: 10.1007/s10661-020-8119-3.
This study investigates the potential factors that contribute to frequent high levels of ozone in Bangu, one of the most critical areas in the city of Rio de Janeiro, regarding ozone levels and air quality. Speciated non-oxygenated volatile organic compounds (VOCs) were measured using method TO-15 (US EPA). The measured concentrations and kinetic and mechanistic analysis of VOC reactivity showed that alkanes were the most important compounds. Ozone concentrations were simulated for a base case representing a day with high ozone levels. Simulated results and statistical multivariate analysis showed that the high ozone concentrations did not seem to be closely related to local emissions but rather were related to pollutant transport and low measured NO levels and were triggered by photochemical activity. The differences between weekdays and weekends were also investigated, showing that ozone concentrations were also higher during weekends, mainly on Sunday, when the diesel heavy vehicle fleet was reduced and lower NO emissions were observed. The VOC/NO ratios correspond to a VOC-limited process, which leads to higher ozone concentrations under low NO conditions.
本研究旨在探讨里约热内卢市污染最严重地区之一班古频繁出现高浓度臭氧的潜在因素，重点关注臭氧水平和空气质量。使用方法 TO-15（美国环保署）测量了特定的非含氧挥发性有机化合物 (VOC)。测量浓度以及 VOC 反应性的动力学和机械分析表明，烷烃是最重要的化合物。模拟了一个代表臭氧水平较高的基础案例的臭氧浓度。模拟结果和统计多元分析表明，高臭氧浓度似乎与当地排放无关，而与污染物输送和低测量的 NO 水平有关，并且是由光化学活性引发的。还研究了工作日和周末之间的差异，结果表明臭氧浓度在周末也较高，主要是在周日，此时柴油重型车队减少，观察到的 NO 排放量较低。VOC/NO 比值对应于 VOC 受限过程，这导致在低 NO 条件下臭氧浓度升高。
