Abstract Near real-time measurements of submicron particulate matter (PM1) were carried out at an industrial and coastal site in Dunkirk (Northern France) over a 14-month period (July 2013–September 2014). This site is surrounded by various industrial plants (metallurgy, petrochemistry, food processing, power plant, etc.) and is characterized by intense ship traffic (~700–800 per day along the English Channel) in harbour surroundings. The non-refractory (NR) submicron particles (organics, sulfate, nitrate, ammonium and chloride) and black carbon were measured by an Aerosol Chemical Speciation Monitor (ACSM) and an Aethalometer, respectively. Concomitant monitoring of CO2, SO2, and meteorological parameters was also performed. Both the seasonal (five seasons including two summers) and spatial (four identified sectors of emissions: marine, urban, industrial-urban and industrial) variabilities were investigated. We present a descriptive analysis of the PM1 composition, whose ambient concentrations ranged from less than 1 μg m−3 up to approximately 100 μg m−3 during a few pollution events. Gaseous SO2 and particulate SO4 were systematically observed at high concentrations (up to 310 and 48.2 μg m−3, respectively) when industrial plumes reached the monitoring site. The conversion ratio of particulate (Sp) to total (Stot) sulfur is relatively constant at 0.1 when RH ranges from 30 to 70% but reaches an average value of 0.3 at high RH (90–100%). This reflects an enhancement of SO2-to-SO4 gas-particle conversion processes resulting in an increase of aerosol acidity as shown by a comparison between measured and predicted NH4 concentrations. An impact of the vertical mixing on the SO2-to-SO4 conversion was also observed using vertical turbulence (σw) as a descriptive parameter. Indeed, the conversion ratio (Sp/Stot) was found to be reduced under high turbulence conditions due to dilution effects.

中文翻译：

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法国城市背景和受工业影响的沿海地区近实时 PM1 化学成分测量超过一年：含硫排放的时间变化和评估

摘要 在 14 个月期间（2013 年 7 月至 2014 年 9 月），在敦刻尔克（法国北部）的一个工业和沿海地区对亚微米颗粒物 (PM1) 进行了近实时测量。该场地周围环绕着各种工业工厂（冶金、石化、食品加工、发电厂等），其特点是港口周围的船舶交通繁忙（沿英吉利海峡每天约 700-800 艘）。非耐火 (NR) 亚微米颗粒（有机物、硫酸盐、硝酸盐、铵和氯化物）和黑碳分别通过气溶胶化学形态监测器 (ACSM) 和风量计测量。还同时监测了 CO2、SO2 和气象参数。季节性（五个季节，包括两个夏季）和空间（四个确定的排放部门：海洋、城市、工业-城市和工业）变量进行了调查。我们对 PM1 成分进行了描述性分析，在一些污染事件期间，其环境浓度范围从小于 1 μg m-3 到大约 100 μg m-3。当工业烟羽到达监测地点时，系统观察到高浓度（分别高达 310 和 48.2 μg m-3）的气态 SO2 和颗粒 SO4。当 RH 范围为 30% 至 70% 时，颗粒 (Sp) 与总硫 (Stot) 的转化率相对恒定为 0.1，但在高 RH (90-100%) 时达到平均值 0.3。这反映了 SO2 到 SO4 气体颗粒转化过程的增强，导致气溶胶酸度增加，如测量和预测的 NH4 浓度之间的比较所示。使用垂直湍流 (σw) 作为描述参数也观察到垂直混合对 SO2 到 SO4 转化的影响。事实上，由于稀释效应，在高湍流条件下发现转化率 (Sp/Stot) 会降低。