a Department of Environmental Medicine , New York University , Tuxedo , New York , USA.
b Department of Forestry and Environmental Science , Shahjalal University of Science and Technology , Sylhet , Bangladesh.
J Air Waste Manag Assoc. 2019 Apr;69(4):478-501. doi: 10.1080/10962247.2018.1548388. Epub 2019 Jan 22.
Dhaka, the capital of Bangladesh, is among the most polluted cities in the world. This research evaluates seasonal patterns, day-of-week patterns, spatial gradients, and trends in PM (<2.5 µm in aerodynamic diameter), PM (<10 µm in aerodynamic diameter), and gaseous pollutants concentrations (SO, NO, CO, and O) monitored in Dhaka from 2013 to 2017. It expands on past work by considering multiple monitoring sites and air pollutants. Except for ozone, the average concentrations of these pollutants showed strong seasonal variation, with maximum during winter and minimum during monsoon, with the pollution concentration of PM and PM being roughly five- to sixfold higher during winter versus monsoon. Our comparisons of the pollutant concentrations with Bangladesh NAAQS and U.S. NAAQS limits analysis indicate particulate matter (PM and PM) as the air pollutants of greatest concern, as they frequently exceeded the Bangladesh NAAQS and U.S. NAAQS, especially during nonmonsoon time. In contrast, gaseous pollutants reported far fewer exceedances throughout the study period. During the study period, the highest number of exceedances of NAAQS limits in Dhaka City (Darus-Salam site) were found for PM (72% of total study days), followed by PM (40% of total study days), O (1.7% of total study days), SO (0.38% of total study days), and CO (0.25% of total study days). The trend analyses results showed statistically significant positive slopes over time for SO (5.6 ppb yr, 95% confidence interval [CI]: 0.7, 10.5) and CO (0.32 ppm yr, 95% CI: 0.01, 0.56), which suggest increase in brick kilns operation and high-sulfur diesel use. Though statistically nonsignificant annual decreasing slopes for PM (-4.6 µg/m yr, 95% CI: -12.7, 3.6) and PM (-2.7 µg/m yr, 95% CI: -7.9, 2.5) were observed during this study period, the PM concentration is still too high (~ 82.0 µg/m) and can cause severe impact on human health. Implications: This study revealed key insights into air quality challenges across Dhaka, Bangladesh, indicating particulate matter (PM) as Dhaka's most serious air pollutant threat to human health. The results of these analyses indicate that there is a need for immediate further investigations, and action based on those investigations, including the conduct local epidemiological PM exposure-human health effects studies for this city, in order to determine the most public health effective interventions.
达卡，孟加拉国的首都，是世界上污染最严重的城市之一。本研究评估了 2013 年至 2017 年期间在达卡监测到的 PM(<2.5μm 空气动力学直径)、PM(<10μm 空气动力学直径)和气态污染物浓度(SO、NO、CO 和 O)的季节性模式、周内模式、空间梯度和趋势。它扩展了过去的工作，考虑了多个监测站点和空气污染物。除臭氧外，这些污染物的平均浓度表现出很强的季节性变化，冬季最高，季风最低，冬季 PM 和 PM 的污染浓度比季风高约五到六倍。我们将污染物浓度与孟加拉国 NAAQS 和美国 NAAQS 限值分析进行比较，表明颗粒物(PM 和 PM)是最令人关注的空气污染物，因为它们经常超过孟加拉国 NAAQS 和美国 NAAQS，尤其是在非季风时期。相比之下，在整个研究期间，气态污染物报告的超标情况要少得多。在研究期间，在达卡市(Darus-Salam 站点)，NAAQS 限值超标最多的是 PM(占总研究天数的 72%)，其次是 PM(占总研究天数的 40%)、O(占总研究天数的 1.7%)、SO(占总研究天数的 0.38%)和 CO(占总研究天数的 0.25%)。趋势分析结果显示，SO(5.6 ppb yr，95%置信区间[CI]：0.7，10.5)和 CO(0.32 ppm yr，95% CI：0.01，0.56)的时间呈统计学上显著的正斜率，这表明砖窑作业和高硫柴油使用增加。尽管在本研究期间观察到 PM(-4.6 µg/m yr，95% CI：-12.7，3.6)和 PM(-2.7 µg/m yr，95% CI：-7.9，2.5)的年递减斜率在统计学上无显著意义，但 PM 浓度仍过高(~82.0 µg/m)，可能对人类健康造成严重影响。影响：本研究揭示了孟加拉国达卡空气质量挑战的关键见解，表明颗粒物(PM)是达卡对人类健康最严重的空气污染物威胁。这些分析结果表明，需要立即进行进一步调查，并根据这些调查采取行动，包括为该市进行当地的 PM 暴露-人类健康影响流行病学研究，以确定最有效的公共卫生干预措施。
