Increasing ambient surface ozone levels over the UK accompanied by fewer extreme events
Increasing ambient surface ozone levels over the UK accompanied by fewer extreme events
复制标题
DOI：
10.1016/j.atmosenv.2020.117627
复制
发表时间：
2020-09-15
影响因子：
5
通讯作者：
Palmer, Paul, I
中科院分区：
文献类型：
--
作者：
Finch, Douglas P.;Palmer, Paul, I
我们报告了1999-2019年英国地面臭氧（O-3）测量的统计分析。数据来自自动城市和农村网络（AURN），该网络构成了检查全国范围内环境空气质量指令遵守情况的基础。我们确定所有AURN站点的平均O-3趋势为0.41 +/- 0.07 μ g m（-3）yr（-1），由郊区和城市环境中的大趋势组成（0.36 +/- 0.11 μ g m（-3）yr（-1）-0.75 +/- 0.16 μ g m（-3）yr（-1））（0.16 +/- 0.07 μ g m（-3）yr（-1））;因此，英国城市和农村地表臭氧浓度之间的差距已经从20 μ g m（-3）稳步下降到12 μ g m（-3）直到2012年，它一直停滞不前。城市表面O-3的这些趋势与NO2（NOx的代理）表面浓度的显著下降相一致，并可能是由NO2（NOx的代理）表面浓度的显著下降引起的，我们将其与交通部门的排放量减少联系起来。使用伽马概率分布来描述表面O-3的变化，我们发现高平均O-3的概率增加，极端（升高）O-3事件的概率相应降低。我们没有发现明显的趋势，每年的天数超过8小时平均O-3值100 μ g m（-3）由英国环境，食品和农村事务部（Defra）或类似的度量120 μ g m（-3）由欧盟设置。这些事故通常发生在整个网络的夏季，范围从2010年的499起事故到2003年和2006年的2300起事故。我们发现，其中50%的超标发生在农村（城市）环境中温度高于18摄氏度（21摄氏度）时。6600万英国居民中有50%（95%）生活和工作在距离AURN站点12公里（50公里）的范围内，我们的分析与英国大部分人口相关。因此，我们可能需要重新确定流行病学研究的优先次序，以了解长期暴露于平均O-3浓度升高对人类健康的影响。
We report a statistical analysis of surface ozone (O-3) measurements over the UK, 1999-2019. Data are from the Automatic Urban and Rural Network (AURN) that forms the basis of checking nationwide compliance with ambient air quality directives. We determine the mean O-3 trend across all AURN sites to be 0.41 +/- 0.07 mu g m(-3)yr(-1), composed of larger trends in suburban and urban environments (0.36 +/- 0.11 mu g m(-3)yr(-1)-0.75 +/- 0.16 mu g m(-3)yr(-1)) than in the rural environment (0.16 +/- 0.07 mu g m(-3)yr(-1)); consequently the gap between urban and rural surface O-3 across the UK has steadily declined from 20 mu g m(-3) to 12 mu g m(-3) until 2012 when it has since stalled. These trends in urban surface O-3 are coincident with and likely caused by a pronounced decline in surface concentrations of NO2 (proxy for NOx), which we link to reduced emissions from the transport sector. Using a gamma probability distribution to describe changes in surface O-3, we find an increase in the probability of high mean O-3 and an associated decrease in the probability of extreme (elevated) O-3 events. We find no discernible trend in the number of days per year that exceed the 8-h mean O-3 value of 100 mu g m(-3) set by the UK Department for Environment, Food and Rural Affairs (Defra) or a similar metric of 120 mu g m(-3) set by the EU. These exceedances, typically occurring during summer months across the network, range from 499 exceedances in 2010 to in excess of 2300 exceedances in 2003 and 2006. We find that 50% of these exceedances occur at temperatures greater than 18 degrees C (21 degrees C) in rural (urban) environments. With 50% (95%) of the 66 million UK inhabitants living and working within 12 km (50 km) of an AURN site, our analysis is relevant to a large fraction of the UK population. Consequently, we may need to re-prioritize epidemiological studies to understand the impact of chronic exposure to elevated mean O-3 concentrations on human health.