Diurnal variability of polycyclic aromatic compound (PAC) concentrations: Relationship with meteorological conditions and inferred sources
Diurnal variability of polycyclic aromatic compound (PAC) concentrations: Relationship with meteorological conditions and inferred sources
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DOI：
10.1016/j.atmosenv.2015.09.050
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发表时间：
2015-12-01
影响因子：
5
通讯作者：
Harrison, Roy M.
中科院分区：
文献类型：
--
作者：
Alam, Mohammed S.;Keyte, Ian J.;Harrison, Roy M.
多环芳烃（PAH）及其硝基和氧代衍生物已在冬季在英国伯明翰的两个地点每三小时采样一周。一个地点受道路交通影响很大，靠近居民住宅，而另一个地点是背景城市位置，距离两个排放源都有一定距离。沿着两个采样点之间的浓度比率，对浓度的时间序列进行了检查。通过计算18：00-21：00 h相对于06：00-09：00 h的浓度比，对平均日分布图进行比较，显示出不同的行为模式。这使得那些化合物的识别与交通相关的最大值在06：00-09：00小时，主要是低分子量的多环芳烃，以及大量的醌类和硝基多环芳烃的强贡献。由于两个时间段的平均温度几乎相同，因此蒸汽和颗粒形式之间的分配变化不太可能影响该比率。大多数化合物在晚上的浓度显示出明显的增加，这是由于住宅供暖排放。以该来源为主的化合物显示出18：00-21：00浓度相对于06：00-09：00浓度的高比率，并且包括较高分子量的PAH和大量的醌类和硝基PAH。通常作为生物质燃烧指标的retene的行为表明，木材烟雾仅是PAH及其衍生物晚高峰的一个贡献者，煤燃烧可能是另一个主要贡献者。多环芳烃浓度随风速的变化表现出与其他主要污染物一致的稀释行为，并观察到高浓度的一系列空气污染物在一个插曲的低温和低风速接近年底的整体采样期与当地的分散过程不佳。从一个短暂的夏季运动的结果给出了一些硝基多环芳烃形成的大气化学反应的迹象。(C)2015年，作者。爱思唯尔有限公司出版
Polycyclic aromatic hydrocarbons (PAH) and their nitro and oxy derivatives have been sampled every three hours over one week in winter at two sites in Birmingham UK. One site is heavily influenced by road traffic and is close to residential dwellings, while the other site is a background urban location at some distance from both sources of emission. The time series of concentrations has been examined along with the ratio of concentrations between the two sampling sites. A comparison of averaged diurnal profiles has shown different patterns of behaviour which has been investigated through calculating ratios of concentration at 18:00-21:00 h relative to that at 06:00-09:00 h. This allows identification of those compounds with a strong contribution to a traffic-related maximum at 06:00-09:00 h which are predominantly the low molecular weight PAHs, together with a substantial group of quinones and nitro-PAHs. Changes in partitioning between vapour and particulate forms are unlikely to influence the ratio as the mean temperature at both times was almost identical. Most compounds show an appreciable increase in concentrations in the evening which is attributed to residential heating emissions. Compounds dominated by this source show high ratios of 18:00-21:00 concentrations relative to 06:00-09:00 concentrations and include higher molecular weight PAH and a substantial group of both quinones and nitro-PAH. The behaviour of retene, normally taken as an indicator of biomass burning, is suggestive of wood smoke only being one contributor to the evening peak in PAH and their derivatives, with coal combustion presumably being the other main contributor. Variations of PAH concentrations with wind speed show a dilution behaviour consistent with other primary pollutants, and high concentrations of a range of air pollutants were observed in an episode of low temperatures and low wind speeds towards the end of the overall sampling period consistent with poor local dispersion processes. Results from a short summer campaign give indications of the formation of some nitro-PAH by atmospheric chemical reactions. (C) 2015 The Authors. Published by Elsevier Ltd.