Hong Kong's Environmental Protection Department recorded higher than normal air pollution levels from the afternoon of October 13, with the health risk category of the Air Quality Health Index reaching "Serious" at some monitoring stations. The department attributed the build-up to weak winds over the city that afternoon, which limited pollutant dispersion, and to intense sunshine that boosted photochemical smog activity, rapidly forming ozone and fine particulates in the Pearl River Delta region. High ozone levels also promoted the formation of nitrogen dioxide.

The Hong Kong Observatory expected a fresh easterly airstream to reach the coast of Guangdong later on October 14, with air quality forecast to improve by then. At "Very High" health risk or above, children, the elderly and people with existing heart or respiratory illnesses were advised to minimise or avoid outdoor physical activity. The general public was advised to reduce outdoor exertion and time outdoors, especially in areas with heavy traffic. The Education Bureau urged schools to check its guidance on protecting students' health, and employers of outdoor workers were advised to assess risks and take preventive measures.

Members of the public could check current AQHI readings on the department's website, and the Centre for Health Protection offered information on the health effects of air pollution. Those in doubt or experiencing discomfort were advised to seek advice from healthcare professionals.