ABSTRACT

Indoor concentrations of PM₁₀, PM_2.5, CO, and CO₂ were measured in 25 naturally ventilated urban residences during the winter and summer seasons in Alexandria, Egypt. Ambient air samples were also collected simultaneously for comparison to indoor measurements. Furthermore, data for air exchange rates, home characteristics, and indoor activities during sampling were collected. It was found that the average indoor PM₁₀, PM_2.5, CO, and CO₂ concentrations for all homes in winter were 119.4 ± 30.9 μg/m³, 85.2 ± 25.8 μg/m³, 1.6 ± 0.8 ppm, and 692.4 ± 144.6 ppm, respectively. During summer, the average indoor levels were 98.8 ± 21.8 μg/m³, 67.8 ± 14.9 μg/m³, 0.5 ± 0.5 ppm, and 558.2 ± 66.2 ppm, respectively. The results indicate that the indoor daily averages of PM₁₀ and PM_2.5 concentrations were higher than the World Health Organization (WHO) guidelines for all selected homes in the two sampling periods. For CO and CO₂ levels, the indoor daily averages for all monitored homes were less than the WHO guideline and the American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ANSI/ASHRAE) Standard 62.1, respectively. A strong seasonal variability was observed, with air quality being particularly poor in winter. Due to increased ventilation rates in summer, indoor levels of air pollutants were strongly dependent on ambient levels, while in winter the indoor concentrations were more strongly affected by indoor sources due to increased human activities and poor ventilation. In addition, stronger indoor/outdoor correlation of air pollutants’ levels was found in summer than in winter probably due to higher ventilation and infiltration in the summer. The study also attempted to understand the potential sources and the various determinants that influence indoor PM, CO, and CO₂ concentrations in the two seasons. The findings can assist policymakers to better understand the indoor air pollution problem and to provide a sound basis for the development of proper national IAQ standards in Egypt.

Implications: Personal exposure is considerably influenced by indoor air pollution which increases health risks. Assessment of indoor air quality has become a more significant issue in Egypt as people tend to spend most of their time inside buildings, especially in their homes. Currently, there is a lack of research on residential indoor air quality in Egyptian cities in terms of the spatial and temporal variation which prevents an accurate assessment of the current situation to develop effective mitigation measures and to establish national indoor air quality standards. This article is considered the first research studying the effect of seasonality on indoor concentrations of PM₁₀, PM_2.5, CO, and CO₂ in urban residences in Alexandria. It also studies the indoor/outdoor relationship of air pollutants’ levels and identifies their major sources as well as the various determinants that influence their indoor concentrations.

摘要

在埃及亚历山大市的冬季和夏季期间，在 25 座自然通风的城市住宅中测量了 PM ₁₀、PM _2.5、CO 和 CO _{2 的}室内浓度。还同时收集了环境空气样本以与室内测量值进行比较。此外，还收集了采样期间空气交换率、家庭特征和室内活动的数据。结果表明，冬季所有家庭的平均室内 PM ₁₀、PM _2.5、CO 和 CO ₂浓度分别为 119.4 ± 30.9 μg/m ³、85.2 ± 25.8 μg/m ³、1.6 ± 0.8 ppm 和 692.4 ± 144。 ppm，分别。夏季，室内平均浓度为 98.8 ± 21.8 μg/m³、67.8 ± 14.9 μg/m ³、0.5 ± 0.5 ppm 和 558.2 ± 66.2 ppm。结果表明，在两个采样期内，所有选定家庭的室内日平均 PM ₁₀和 PM _2.5浓度均高于世界卫生组织 (WHO) 指南。对于 CO 和 CO ₂水平，所有受监控家庭的室内日平均值分别低于 WHO 指南和美国国家标准协会/美国采暖、制冷和空调工程师协会 (ANSI/ASHRAE) 标准 62.1。观察到强烈的季节性变化，冬季空气质量特别差。由于夏季通风率增加，室内空气污染物水平强烈依赖于环境水平，而在冬季，由于人类活动增加和通风不良，室内污染物浓度受室内源的影响更大。此外，夏季空气污染物水平的室内/室外相关性比冬季更强，可能是由于夏季通风和渗透率较高。两个季节的_2个浓度。调查结果可以帮助决策者更好地了解室内空气污染问题，并为埃及制定适当的国家室内空气质量标准提供良好的基础。

影响: 室内空气污染对个人暴露的影响很大，这会增加健康风险。在埃及，室内空气质量评估已成为一个更重要的问题，因为人们倾向于将大部分时间花在建筑物内，尤其是在家中。目前，缺乏对埃及城市住宅室内空气质量时空变化的研究，这阻碍了对当前状况的准确评估，以制定有效的缓解措施并建立国家室内空气质量标准。本文被认为是研究季节性对室内 PM ₁₀、PM _2.5、CO 和 CO ₂浓度影响的第一项研究在亚历山大的城市住宅中。它还研究了空气污染物水平的室内/室外关系，并确定了它们的主要来源以及影响其室内浓度的各种决定因素。