Health Impacts of PM2.5 in Northern India

Recent studies have shed light on the alarming levels of PM2.5 pollution in Northern India, particularly in the Indo-Gangetic Plain. The research published in *Nature Communications* has identified the sources and health impacts of particulate matter. It marks the dominance of local emissions and combustion processes in contributing to PM2.5 levels.

About PM2.5 Composition

PM2.5 refers to particulate matter with a diameter of less than 2.5 micrometres. This study analysed samples from five locations, including urban, roadside, rural, and industrial sites. It found that PM2.5 in Delhi is largely composed of ammonium chloride and organic aerosols. These are primarily from vehicle emissions, residential heating, and fossil fuel combustion. Outside Delhi, ammonium sulfate and biomass-burning aerosols are more prevalent.

Health Risks of PM2.5

The oxidative potential of PM2.5 is health concern. This potential is influenced by organic aerosols resulting from the incomplete combustion of biomass and fossil fuels. The study indicates that these aerosols are a major contributor to health risks associated with PM2.5 exposure. High concentrations of hydrocarbon-like organic aerosols were recorded, particularly at urban roadside sites in Delhi.

Seasonal Variations in PM2.5 Concentrations

The study observed that hydrocarbon-like organic aerosol concentrations remain relatively stable throughout the year. However, during colder months, the combustion of cow dung for heating and cooking leads to increase in primary organic aerosols. These concentrations can be up to ten times higher in winter compared to warmer months.

Comparative Analysis of PM2.5 Levels

The oxidative potential of PM2.5 in Indian cities is notably high. It can exceed levels found in cities across China and Europe by a factor of five. This alarming statistic puts stress on the need for urgent action to address air quality issues in Northern India.

Policy Implications

The findings of this study are crucial for policymakers. They reveal the importance of targeting local emission sources to mitigate health risks. Effective air quality control strategies should focus on reducing emissions from incomplete combustion processes.

Conclusion

The study provides valuable vital information about the sources and health impacts of PM2.5 in Northern India. It marks the urgent need for effective measures to tackle air pollution and protect public health.

Questions for UPSC:

1. Critically analyse the health impacts of PM2.5 pollution in urban areas.
2. What are the primary sources of PM2.5 in India? Explain their contributions.
3. Comment on the seasonal variations in PM2.5 concentrations and their implications for public health.
4. Explain the role of local combustion processes in contributing to air pollution. How can these be effectively managed?

Answer Hints:

1. Critically analyse the health impacts of PM2.5 pollution in urban areas.

1. PM2.5 is linked to respiratory and cardiovascular diseases due to its ability to penetrate deep into the lungs.
2. Oxidative potential of PM2.5 increases health risks, influenced by organic aerosols from incomplete combustion.
3. High concentrations of hydrocarbon-like organic aerosols in urban areas exacerbate health issues.
4. Comparative studies show PM2.5’s oxidative potential in Indian cities is among the highest globally, increasing health risks.
5. Vulnerable populations, including children and the elderly, are particularly at risk from PM2.5 exposure.

2. What are the primary sources of PM2.5 in India? Explain their contributions.

1. Vehicular emissions in urban areas contribute , with organic aerosols accounting for 20-40% of total organic aerosols mass.
2. Residential heating and cooking, especially using biomass like cow dung, are major sources during colder months.
3. Industrial emissions and fossil fuel combustion also play a critical role in PM2.5 levels, particularly outside urban centers.
4. Ammonium sulfate and nitrate from agricultural practices contribute to PM2.5 pollution in rural areas.
5. Local combustion processes dominate PM2.5 pollution, varying by region and season.

3. Comment on the seasonal variations in PM2.5 concentrations and their implications for public health.

1. PM2.5 concentrations are generally stable, but increase during winter due to biomass burning for heating.
2. Cold-season primary organic aerosols can be up to ten times higher than in warmer months, worsening air quality.
3. Shallower boundary layer conditions in winter trap pollutants closer to the ground, increasing health risks.
4. Higher levels of PM2.5 during cold months correlate with increased respiratory illnesses and hospital admissions.
5. Public health strategies must consider seasonal variations to effectively mitigate health impacts.

4. Explain the role of local combustion processes in contributing to air pollution. How can these be effectively managed?

1. Local combustion processes, such as burning biomass and fossil fuels, are primary contributors to PM2.5 pollution.
2. These processes release organic aerosols, which have oxidative potential, impacting health.
3. Improving combustion efficiency and transitioning to cleaner energy sources can reduce emissions .
4. Policy measures should target local sources, promoting cleaner cooking and heating technologies.
5. Community awareness and education on the health impacts of inefficient combustion can drive behavioral change.