Decades of land use change and its impact on air quality in Egypt’s Middle Nile Delta observed from space – Nature

Report on Land Use Change and Air Quality in Gharbia Governorate in the Context of Sustainable Development Goals

Executive Summary

This report analyzes the environmental impact of significant land use and land cover (LULC) changes in Egypt’s Gharbia Governorate over a 20-year period (2003-2023). Utilizing remote sensing and GIS technologies, the study quantifies the conversion of agricultural land to urban areas and assesses the corresponding impact on air quality. The findings reveal a direct correlation between urban expansion and increased concentrations of atmospheric pollutants, including PM_2.5, CO, NO₂, and SO₂. This trend presents significant challenges to achieving multiple Sustainable Development Goals (SDGs), particularly SDG 3 (Good Health and Well-being), SDG 11 (Sustainable Cities and Communities), and SDG 15 (Life on Land). The data underscores the urgent need for integrated land management and environmental policies to mitigate the adverse effects of urbanization and advance the 2030 Agenda for Sustainable Development.

1.0 Introduction: Urbanization and its Challenge to the SDGs

Rapid urbanization and the associated changes in land use are critical factors influencing environmental sustainability. In Gharbia Governorate, uncontrolled urban sprawl has led to the significant loss of fertile agricultural land, directly undermining SDG 15 (Life on Land) by degrading terrestrial ecosystems and threatening SDG 2 (Zero Hunger) by reducing food production capacity. Furthermore, this transformation has severe implications for air quality, a key determinant of public health. The resulting increase in air pollution poses a direct threat to SDG 3 (Good Health and Well-being) and complicates efforts to build inclusive, safe, and resilient urban environments as outlined in SDG 11 (Sustainable Cities and Communities). This study provides a critical assessment of these interconnected challenges by linking LULC dynamics with air quality trends, offering vital data for evidence-based policymaking aimed at sustainable development.

2.0 Methodology for Monitoring Environmental Change

To assess the progress toward environmental sustainability targets, this study employed a multi-source satellite data approach.

2.1 Land Use/Land Cover (LULC) Analysis

• Data Source: Landsat 5 (2003) and Landsat 8 (2013, 2023) satellite imagery.
• Classification Method: A Maximum Likelihood Classifier (MLC) was used to categorize the landscape into two primary classes: cultivated land and urban areas.
• Objective: To quantify the rate and spatial pattern of urban expansion and agricultural land loss, providing key indicators for monitoring SDG 11.3 (sustainable urbanization) and SDG 15.3 (combating land degradation).

2.2 Air Quality Assessment

• Data Sources:
  1. Aqua and Terra (MODIS) satellites for estimating PM_2.5 concentrations.
  2. Sentinel-5P satellite for measuring CO, NO₂, and SO₂ concentrations for the year 2023.
• Processing: Satellite data was processed to derive seasonal average concentrations of key pollutants, which were then mapped to identify spatial hotspots.
• Objective: To evaluate ambient air quality in relation to land use patterns, providing critical data for SDG 3.9 (reduce deaths from pollution) and SDG 11.6 (reduce the environmental impact of cities).

3.0 Key Findings: The Environmental Cost of Urban Sprawl

3.1 Land Use Transformation (2003-2023)

The analysis revealed a significant and sustained conversion of productive land to urban infrastructure over the two-decade study period.

• Urban Area Expansion: Urban areas increased by 136.2 km².
• Cultivated Land Decline: Cultivated lands decreased by 135.94 km².

This direct trade-off highlights a critical conflict between urban development and the preservation of natural resources, impacting the foundations of SDG 15 (Life on Land) and regional food security.

3.2 Air Quality Degradation

The assessment of atmospheric pollutants in 2023 identified distinct seasonal patterns and elevated concentrations, particularly in newly urbanized zones.

1. Particulate Matter (PM_2.5): Concentrations ranged from 7.12 to 8.66 µg/m³, peaking in autumn. These fine particles are a primary concern for SDG 3 due to their deep penetration into the respiratory system.
2. Nitrogen Dioxide (NO₂): Levels were highest in autumn (3.13 µg/m³), often linked to traffic emissions and agricultural waste burning, impacting both health and climate (SDG 13: Climate Action).
3. Carbon Monoxide (CO): Concentrations peaked in summer (946.79 µg/m³), indicating incomplete combustion from vehicles and industrial sources.
4. Sulfur Dioxide (SO₂): Levels were highest in winter (8 µg/m³), primarily from the combustion of fossil fuels in industrial and heating applications.

Crucially, the highest concentrations of all measured pollutants were consistently recorded in the recently expanded urban areas, demonstrating a direct link between land use change and air quality deterioration.

4.0 Implications for Sustainable Development

The findings of this report present a clear narrative of unsustainable development patterns in Gharbia Governorate, with direct consequences for several SDGs.

• SDG 11 (Sustainable Cities and Communities): The observed urban sprawl, characterized by the encroachment on agricultural land, is contrary to the principles of compact and sustainable urban planning (Target 11.3). The resulting air pollution directly degrades the urban environment (Target 11.6).
• SDG 3 (Good Health and Well-being): Elevated levels of PM_2.5, NO₂, and other pollutants in densely populated urban areas increase the risk of respiratory and cardiovascular diseases, challenging the achievement of Target 3.9.
• SDG 15 (Life on Land): The irreversible loss of 135.94 km² of fertile cultivated land represents a significant form of land degradation, directly conflicting with the goal of achieving land degradation neutrality (Target 15.3).

5.0 Conclusion and Recommendations for SDG Alignment

This study confirms that unplanned urban expansion in Gharbia Governorate has led to a measurable degradation of both land resources and air quality. The use of space-borne technologies provides an effective framework for monitoring these environmental pressures and their divergence from sustainable development pathways.

To align future development with the SDGs, the following actions are recommended:

1. Integrated Land-Use Planning: Develop and enforce zoning regulations that protect prime agricultural land and promote compact urban growth, in line with SDG 11 and SDG 15.
2. Strengthen Air Quality Management: Implement targeted air pollution control strategies in industrial and high-traffic urban centers, informed by continuous monitoring, to protect public health as mandated by SDG 3.
3. Promote Sustainable Practices: Encourage alternatives to agricultural waste burning and invest in cleaner industrial technologies to reduce precursor emissions for NO₂ and SO₂, contributing to SDG 13.

The data generated provides a valuable foundation for policymakers to formulate strategies that balance development needs with environmental protection, ensuring a more sustainable and healthy future for the residents of Gharbia Governorate.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

• SDG 3: Good Health and Well-being: The article’s central theme is the impact of air pollution on public health. It investigates pollutants like PM_2.5, CO, NO₂, and SO₂, which are known to have “adverse health and ecological effects.” The study’s focus on monitoring these pollutants directly relates to ensuring healthy lives and promoting well-being.
• SDG 11: Sustainable Cities and Communities: This goal is extensively addressed. The article analyzes “urban sprawl” and “uncontrolled urban expansion” in Gharbia Governorate. It highlights the negative environmental consequences of this expansion, specifically the “deterioration of air quality.” The findings emphasize the “need for integrated land-use planning and air pollution control” to make cities more sustainable, which is a core component of SDG 11.
• SDG 15: Life on Land: The study documents a significant decline in “cultivated lands” by 135.94 km² between 2003 and 2023 due to urban expansion. This conversion of fertile agricultural land into built-up areas represents a form of land degradation and a loss of terrestrial ecosystems. The article’s analysis of Land Use/Land Cover (LULC) changes and their environmental impacts directly connects to the goal of protecting and restoring terrestrial ecosystems and halting land degradation.

2. What specific targets under those SDGs can be identified based on the article’s content?

• Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination. The article directly supports this target by monitoring and quantifying harmful air pollutants (PM_2.5, CO, NO₂, SO₂) that contribute to illnesses. The study’s purpose is to understand the sources and levels of this pollution to inform control strategies.
• Target 11.3: By 2030, enhance inclusive and sustainable urbanization and capacity for participatory, integrated and sustainable human settlement planning and management in all countries. The article’s findings reveal a trend of unsustainable urbanization, where “urban areas increased by 136.2 km²” at the expense of agricultural land. The conclusion explicitly calls for “integrated land-use planning” and “sustainable development strategies,” directly aligning with the objective of this target.
• Target 11.6: By 2030, reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality and municipal and other waste management. The study’s core investigation is the link between urban sprawl and deteriorating air quality. It finds that “the highest pollutant levels were consistently recorded in the recently expanded urban areas,” demonstrating the adverse environmental impact of cities and underscoring the need to manage urban air quality.
• Target 15.3: By 2030, combat desertification, restore degraded land and soil, including land affected by desertification, drought and floods, and strive to achieve a land degradation-neutral world. The conversion of “fertile agricultural land” into urban areas, as documented in the article (“cultivated lands declined by 135.94 km²“), is a clear example of land degradation. The study provides the data necessary to assess the extent of this degradation, which is the first step toward restoration and achieving neutrality.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

• Indicator 11.6.2: Annual mean levels of fine particulate matter (e.g. PM_2.5 and PM₁₀) in cities (population weighted). The article explicitly measures and reports on the concentration of PM_2.5. It provides seasonal mean values, such as the autumn peak of 8.66 µg/m³. It also measures other key pollutants like CO (946.79 µg/m³ in summer), NO₂ (3.13 µg/m³ in autumn), and SO₂ (8 µg/m³ in winter), which are crucial metrics for assessing urban air quality.
• Indicator 11.3.1: Ratio of land consumption rate to population growth rate. While the article does not calculate the final ratio, it provides the essential data for the “land consumption rate” component. It quantifies the rate of urban expansion, stating that “urban areas increased by 136.2 km²” over a 20-year period (2003-2023). This data is a direct measure of land consumption.
• Indicator 15.3.1: Proportion of land that is degraded over total land area. The article provides the necessary data to calculate this indicator. It identifies the degradation of land through the conversion of “cultivated land” to “urban area.” The study quantifies this change, noting a decline of 135.94 km² in cultivated land, which can be used to determine the proportion of degraded land within the Gharbia Governorate’s total area of 1943.27 km².

4. Summary Table of SDGs, Targets, and Indicators

Source: nature.com