Understanding the Air Quality Health Index (AQHI)
The Air Quality Health Index (AQHI) is a system used in Hong Kong to measure and report air quality. It categorizes air quality into five levels: low, moderate, high, very high, and serious. The “serious” level is the highest and indicates a significant health risk for everyone, not just sensitive groups like children, the elderly, or those with pre-existing health conditions.
At the “serious” level, pollutants such as PM10 and PM2.5 are present in high concentrations. PM10 refers to particulate matter smaller than 10 micrometers, while PM2.5 is even finer, at 2.5 micrometers or less. These particles can penetrate deep into the lungs and even enter the bloodstream, causing respiratory and cardiovascular issues.
The Environmental Protection Department (EPD) provides real-time updates on the AQHI, allowing the public to make informed decisions about outdoor activities. Monitoring stations across Hong Kong, including Central, Mong Kok, and Tai Po, report these levels hourly.
Impact on Outdoor Activities
When the AQHI reaches “serious,” outdoor activities become risky. Strenuous activities like jogging, cycling, or playing sports can increase the amount of polluted air inhaled, worsening health effects. Children and the elderly are particularly vulnerable, as their bodies are less able to cope with the stress of poor air quality.
Schools and sports organizations often cancel or reschedule outdoor events during such periods. For example, schools may move physical education classes indoors, and sports clubs may postpone matches. It’s crucial to check the AQHI before planning any outdoor activity. The EPD’s website and mobile app provide real-time updates to help people stay informed.
Causes and Sources of Air Pollution
The current spike in air pollution is caused by a dusty northerly airstream, which carries pollutants from the mainland to Hong Kong. This airstream, combined with the northeastern monsoon, traps particulate matter in the air, leading to higher concentrations of PM10 and PM2.5.
Industrial emissions, vehicle exhaust, and construction dust are major contributors to these pollutants. For instance, PM10 levels surged from Saturday night, with concentrations exceeding safe limits in multiple areas. Regional pollution, particularly from mainland China, also plays a significant role in Hong Kong’s air quality issues.
Health Risks and Precautions
Exposure to “serious” air quality levels can lead to immediate health problems like coughing, shortness of breath, and chest tightness. Long-term exposure increases the risk of chronic respiratory diseases, heart disease, and even lung cancer. People with asthma, heart conditions, or other chronic illnesses are especially at risk.
To protect yourself, stay indoors as much as possible. Use air purifiers to improve indoor air quality and wear masks rated N95 or higher if you must go outside. Avoid strenuous activities and monitor symptoms like dizziness or difficulty breathing. Seek medical advice if symptoms persist.
Government and Community Responses
The Hong Kong government has issued health advisories and is closely monitoring air quality through the EPD. Schools and organizations have canceled outdoor activities to protect students and staff. Community initiatives, such as public awareness campaigns, encourage people to reduce their carbon footprint by using public transportation and conserving energy.
Long-term strategies include promoting green infrastructure, such as urban forests and green roofs, to absorb pollutants. The government is also working on regional cooperation with mainland China to address cross-border pollution.
By staying informed and taking precautions, individuals can reduce their exposure to harmful air pollutants and contribute to improving air quality in Hong Kong.
