Air quality in the Maritime Continent, which worsens particularly during peatland fire periods, causes climate and environmental concerns. The occurrence of peatland fire haze has been related to the interannual variations of the El Niño-Southern Oscillation, Indian Ocean Dipole, and inter-seasonal monsoon cycle. However, the factors affecting the region's air quality on subseasonal timescales have not been clearly identified. We investigated the role of the Madden-Julian Oscillation (MJO), which has a 30–90-day cycle, in air quality using a long-term observation data set from Malaysia. The results show that in MJO Phase 3, during which the region is covered by convective clouds, only accounted for 4 ± 2% of high PM₁₀ concentration days (daily average PM₁₀ concentration at site X > average + standard deviation of daily average PM₁₀ concentration at site X) among all active MJO periods. In contrast, the corresponding values were considerably higher in MJO Phases 1 and 5–8. The MJO also modulated CO and ozone concentrations. This study shows that the MJO influences air quality during both fire and non-fire seasons, demonstrating that variations in wildfire activity are not the only cause of air quality changes. Other factors, such as precipitation, also need to be considered to better understand the relationship between the MJO and air quality.

中文翻译：

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Madden-Julian 振荡调节海洋大陆的空气质量

海洋大陆的空气质量尤其在泥炭地火灾期间恶化，导致气候和环境问题。泥炭地火霾的发生与厄尔尼诺-南方涛动、印度洋偶极子和季风周期的年际变化有关。然而，在亚季节时间尺度上影响该地区空气质量的因素尚未明确。我们使用来自马来西亚的长期观测数据集调查了周期为 30-90 天的 Madden-Julian Oscillation (MJO) 在空气质量中的作用。结果表明，在 MJO 3 期，该地区被对流云覆盖，仅占 PM ₁₀高浓度日（现场日平均 PM ₁₀浓度）的4±2%X  > 平均值 +站点X处每日平均 PM ₁₀浓度的标准偏差）在所有活动 MJO 期间。相比之下，MJO 阶段 1 和 5-8 中的相应值要高得多。MJO 还调节了 CO 和臭氧浓度。这项研究表明，MJO 在火灾和非火灾季节都会影响空气质量，这表明野火活动的变化并不是空气质量变化的唯一原因。还需要考虑其他因素，例如降水，以更好地了解 MJO 与空气质量之间的关系。