Digital News Desk:
The Air Quality Index (AQI) is a measurement system designed to communicate the quality of air in a specific area on a daily basis. It provides a clear indication of whether the air is safe to breathe, along with potential health implications for the public. Understanding AQI is critical, especially in cities where air pollution is a significant public health issue. The AQI is calculated based on the concentration of various pollutants, such as particulate matter (PM2.5 and PM10), ground-level ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2).
What is AQI?
The AQI converts the concentration levels of individual pollutants into a number that ranges from 0 to 500, where a lower number represents cleaner air and a higher number signifies more polluted air. The AQI is broken into different categories, each associated with a specific health advisory to alert the public about potential risks. The pollutants considered in the AQI calculation can vary from country to country, but the most common ones include particulate matter (PM2.5 and PM10), ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide.
AQI Categories
The AQI is divided into six categories, each indicating a different level of air quality and health concern:
- Good (0-50): Air quality in this range is considered satisfactory, and air pollution poses little to no risk. The sky is typically clear, and the atmosphere feels fresh. Individuals can engage in outdoor activities without concern for their health.
- Moderate (51-100): Air quality is acceptable; however, there may be a slight risk for individuals who are particularly sensitive to air pollution, such as those with respiratory conditions like asthma. For the general population, the air quality is still fine for outdoor activities.
- Unhealthy for Sensitive Groups (101-150): In this range, the air quality may start to impact sensitive groups, including children, the elderly, and individuals with heart or lung diseases. These individuals should limit prolonged outdoor exertion. The general population, however, is not likely to be affected at this point.
- Unhealthy (151-200): When the AQI reaches this level, everyone may begin to experience adverse health effects. Sensitive individuals, such as those with pre-existing respiratory conditions, are at a higher risk and may experience more serious effects. Outdoor physical activities should be limited.
- Very Unhealthy (201-300): At this level, the air quality is significantly poor, and health warnings are issued. The risk of health effects increases for everyone, not just sensitive groups. It is advised that people avoid outdoor activities, especially vigorous exercises. Prolonged exposure can cause immediate symptoms like throat irritation and difficulty breathing.
- Hazardous (301-500): This is the most dangerous level of air quality, where emergency conditions are declared. The entire population is likely to experience severe health effects, and outdoor exposure should be avoided altogether. At this stage, the air is considered toxic, and even healthy individuals can develop respiratory or cardiovascular problems after short-term exposure.
Health Implications of Bad AQI
An AQI that exceeds 100 is generally considered unhealthy, particularly for sensitive populations. When AQI reaches the “unhealthy” range (151-200), the risks become more pronounced, even for the general population. Air pollution can exacerbate respiratory issues like asthma, bronchitis, and chronic obstructive pulmonary disease (COPD). Exposure to high levels of pollution can cause cardiovascular stress, increased hospital admissions, and premature death, particularly among vulnerable groups.
Fine particulate matter (PM2.5) is one of the most concerning pollutants when it comes to AQI. These particles are small enough to penetrate deep into the lungs and even enter the bloodstream. Long-term exposure to high levels of PM2.5 has been linked to lung cancer, stroke, and heart disease. Ozone, another pollutant measured by the AQI, can irritate the respiratory system, reduce lung function, and aggravate lung diseases like asthma.
The Role of Weather and Geography
AQI levels can vary widely depending on factors such as weather conditions, geographical location, and time of year. For example, during the colder months, many urban areas experience higher levels of air pollution due to increased heating emissions and atmospheric inversion, where a layer of warm air traps pollutants close to the ground. Cities surrounded by mountains or valleys, such as Delhi or Los Angeles, often have worse air quality because the natural topography traps pollutants, preventing their dispersal.
In many countries, the onset of winter also corresponds with an increase in particulate matter due to stubble burning, especially in agricultural regions like northern India. The burning of biomass, combined with industrial emissions and vehicular pollution, often pushes AQI levels into the hazardous range.
How to Protect Yourself from Poor AQI
When the AQI reaches unhealthy levels, it is important to take steps to reduce exposure to air pollution. Here are some practical steps:
- Stay Indoors: Limit outdoor activities, especially physical exertion, during periods of high pollution.
- Use Air Purifiers: If possible, use air purifiers at home to reduce indoor pollution.
- Wear Masks: Use masks like N95 or higher-rated ones to filter out particulate matter if you need to be outside.
- Keep Windows Closed: Keep windows closed during high pollution days to prevent polluted air from entering your home.
- Check Daily AQI Levels: Use mobile apps and websites that provide real-time updates on AQI levels in your area, so you can plan your day accordingly.
Global AQI Standards
Different countries have slightly varying standards for what constitutes safe or dangerous levels of AQI. In the United States, the Environmental Protection Agency (EPA) uses a detailed scale to provide daily AQI readings. In India, the Central Pollution Control Board (CPCB) monitors air quality and issues daily AQI reports. The World Health Organization (WHO) also provides air quality guidelines but acknowledges that many countries, especially in the developing world, face challenges in meeting these standards.
Conclusion
Understanding the AQI and its implications for health is crucial, especially in regions where air pollution is a constant issue. While many governments and organizations are working to improve air quality, individuals should stay informed about current levels and take precautions when the AQI reaches unhealthy levels. Awareness and action, both at the individual and policy level, are key to mitigating the harmful effects of air pollution on public health.
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