The city of Hong Kong, known for its futuristic sky-scraping skyline, sprawled upward decades ago from the sea, as it became one of the primary shipping ports of Asia. Today, it remains one of the busiest harbors in the world. This acclaim has made the Hong Kong ports both the largest contributor to the local economy, and conversely, the largest contributor to noxious air on the island.

According to the latest emission inventory conducted by the Environmental Protection Department, shipping alone produced 8,540 tonnes of sulphur dioxide, 32,900 tonnes of nitrogen oxide and 1,480 tonnes of PM2.5 pollution, in 2016. While steps have been taken to reduce the industry’s impact on local air - such as a 2015 law requiring marine vessels to use low sulphur fuel while at bay in Hong Kong - more action is needed to better protect citizen health. This is particularly important as the number of vessels received by Hong Kong’s ports rose by 7.8% from 2016 to 2017 - a strong figure for business, but alarming figure for health considerations.

Falling second to shipping, for contributing air pollution in Hong Kong , is electricity generation. The power plants on Castle Peak and Lamma, are two primary offenders. Collectively, the territory’s plants contribute 8,020 tonnes of sulphur dioxide, 25,620 tonnes of nitrogen oxide and 310 tonnes of PM2.5 (more than 1,000 tonnes of PM2.5 less, than shipping).

As troubled as Hong Kong’s air pollution problem may seem, the government’s efforts to curb emissions have made a substantial impact. Since 2011, PM2.5 levels in Causeway Bay have dropped by almost half. Within the last year alone, meanwhile, IQAir AirVisual data shows a 7% improvement from 2017.