HongKong Air Pollution. HongKong overall air quality index is 47. HongKong (fine particulate matter) AQI is 47 - HongKong PM10 (respirable particulate matter) AQI is 14 - HongKong NO2 (nitrogen dioxide) AQI is 34 - HongKong SO2 (sulfur dioxide) AQI is 3 - HongKong O3 (ozone) AQI is 2 - HongKong CO (carbon monoxide) AQI is 6 -.
When concentrations are high for a prolonged period of time, fine particles can build up indoors even though you may not be able to see them. If you are in an at-risk group, don’t wait until pollution reaches the “hazardous” category to take action to reduce your exposure.