Selected non‐methane hydrocarbons (NMHCs) obtained from long‐term operation of the Photochemical Assessment Monitoring Stations (PAMS) in Taipei allowed for the assessment of the effectiveness of emission control measures on ozone precursors from 2007 to 2016. Despite the very pronounced diurnal and seasonal cycles of all the 51 target compounds, almost all species showed various degrees of declining trends over the decade. When dividing the 51 compounds into five groups of alkanes, alkenes, ethyne, aromatics, and isoprene, the decadal trends are assessed as −0.7 ± 0.8, −0.3 ± 0.1, −0.02 ± 0.14, −1.9 ± 1.2, and − 0.09 ± 0.02 ppbC year⁻¹, respectively. Meanwhile, as evidenced by multiple NMHC ratios as effective indicators of atmospheric photochemical conditions, a trend of gradual lessening in the degree of photochemistry over time was noticed. Air masses in Taipei are suggested to be increasingly more contributed by local emissions and less affected by mixing with transboundary or long‐range transported influences.

中文翻译：

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台北特定非甲烷碳氢化合物的年代际趋势

从台北光化学评估监测站（PAMS）的长期运行中获得的一些非甲烷碳氢化合物（NMHC）可以评估2007年至2016年对臭氧前体的排放控制措施的有效性。在所有51种目标化合物的季节性周期中，几乎所有物种在过去十年中均呈现不同程度的下降趋势。将51种化合物分为烷烃，烯烃，乙炔，芳烃和异戊二烯五组时，十年趋势被评估为-0.7±0.8，-0.3±0.1，-0.02±0.14，-1.9±1.2和-0.09± 0.02 ppbC年^-1， 分别。同时，如由多种NMHC比率作为大气光化学条件的有效指标所证明的，注意到随着时间的流逝，光化学度逐渐降低的趋势。建议台北的气团越来越多地受到当地排放的影响，而受跨界或远距离运输影响的混合影响较小。