Air Quality and Health in Cities

• Recently, a report was released titled Air Quality and Health in Cities, which analyzed pollution and global health effects for more than 7,000 cities around the world between 2010 and 2019.

• The State of Global Air (SoGA) is a research and outreach initiative to provide reliable, meaningful information about the air quality around the world.
• The report, Air Quality, and Health in Cities, released by Health Effects Institute’s State of Global Air Initiative, provides a comprehensive and detailed analysis of air pollution and global health impacts for more than 7,000 cities around the world, focusing on two of the most harmful pollutants; fine particulate matter (PM₅) and nitrogen dioxide (NO₂).

Patterns In Urban PM_2.5 Exposure:

• India and Indonesia have seen the most severe increase in PM₅ pollution, whereas China has seen the greatest improvements.
• Delhi and Kolkata are ranked first and second in the list of top 10 most polluted cities when PM 2.5 levels were compared.
• While exposures to PM₅ pollution tend to be higher in cities located in low- and middle-income countries, exposure to NO₂ is high across cities in high-income as well as low- and middle-income countries.

• PM₅ pollution tends to be highest in cities in low- and middle-income countries, whereas NO₂ levels are high in large cities across countries of all income levels.
• No Indian city appeared in the list of top 10 or even top 20 polluted cities when NO2 levels were compared.
• Average NO₂ levels for Delhi, Kolkata, and Mumbai, according to the report, ranged from 20-30 µg/m³.
• NO₂ comes mainly from the burning of fuels in older vehicles, power plants, industrial facilities, and residential cooking and heating.
• As city residents tend to live closer to busy roads with dense traffic, they are often exposed to higher NO₂ pollution than residents of rural areas.
• Other cities with high NO₂ population levels included Moscow, Beijing, Paris, Istanbul, and Seoul.
• A strong link was also found between traffic-related air pollution and lung cancer mortality, asthma onset in children and adults, and acute lower respiratory infections in children.
  
  

• Of all cities analyzed, the 20 cities with the highest PM₅-linked death rates in 2019, 15 are in China, 3 are in Ukraine, and 2 are in Bulgaria.
• Beijing had the largest disease burden associated with a PM 2.5-related illness, with 124 attributable fatalities per 100,000 persons.
• Delhi came in 6^th, with 106 deaths per 100,000, and Kolkata at 8^th with 99 deaths.

Area of Concern:

• Ground-based monitoring stations for NO₂ are even more scarce than those for PM₅, especially in low- and middle-income countries.
• 2022 WHO Air Quality Database reveals that only 117 nations currently have ground-level monitoring systems to track PM 2.5 and PM₁₀, and only 74 nations have ground-based monitoring stations for NO
• In 2019, exposure to pollutants in 86% of the more than 7,000 cities exceeded WHO’s standard, therefore, impacting around 2.6 billion people.

• Extensive comparisons between these satellite-derived estimates and ground-level measurements demonstrate that they are reasonably accurate. They can be reliable indicators of PM₅ and NO₂ exposures where ground monitors do not exist or data are not publicly available.
• Since ground measurements are incorporated in the model, estimates are less reliable for regions with fewer or no air monitoring stations (e.g., cities in Africa and Asia).

• London’s Ultra Low Emission Zone initiative delivered a 36% reduction in NO2 in the first six months after its launch in 2019.
• In Nepal, local entrepreneurs teamed up with experts to help build more efficient, less-polluting kilns using zig-zag technology.
• AirQo was launched in 2015 at Makerere University with the goal of addressing the data gap on air quality in Uganda and across Sub-Saharan Africa.

Collection and digitization of Health records:

• Access to the consistent and systematic collection of city-level health data is crucial to researchers. This can help researchers conduct more accurate and local analyses that inform communities and policymakers.
• Data on the “burden of air pollution on health” are vital for assessing the effectiveness of interventions, both in terms of public health benefits and economic impact.

• Increasing the density of air monitors, which are important to track key pollutants to improve the accuracy of estimates of Pollutant levels
• In addition to setting up monitors, it is important to invest in resources for calibration and maintenance to ensure the quality of data from these monitors.