Air quality in shopping malls varies greatly; if you are weak in any way, watch out

^{New Town Plaza in Sha Tin Photo: HKTB}

If you are going to spend a lot of time in a shopping mall, stop, think and consider air quality. This is especially true if you have respiratory issues or a weak immune system. Air quality in Hong Kong shopping centres varies widely, influenced by road pollution wafting in and internal sources such as food courts.

This realisation hit me after I went for a two-hour visit with the wife to a Shatin shopping mall with hay fever and came out with bronchitis. I was crook for three days coughing up horrible mucus.

Here’s what you should look out for:

• Malls with entrances on busy roads directly inhaling vehicle exhausts, carbon monoxide and particulate matter.
• Some shopping centres, especially older ones, have poorly maintained fresh air intakes and/or ineffective filtration so pollutants are trapped inside.
• A crowded mall especially one with food courts may have much higher than recommended carbon dioxide levels.
• A shopping centre may have poor air because of renovation or cleaning, releasing chemicals and noxious gases.

^{The Hedley Environmental Index shows levels of pollutants around Hong Kong}

Which malls are worst:

• Malls in heavy traffic roadside locations — Central, Causeway Bay, Mongkok, Shatin — suffer most from outdoor pollution wafting in.
• Older malls make have out of date, inefficient ventilation systems.
• Some malls may have high CO2 because of food courts.

Pollutants you need to be aware of:

• Particulate matter from traffic and other sources
• CO2 carbon dioxide
• VOCs (volatile organic compounds) from building materials, furnishing and cleaning
• Bacteria may be high in poorly maintained places

What to do

• Choose newer malls or those with high quality management
• Be aware of food courts and entrances from busy streets
• Check the Hedley* Environmental Index. It will give you readings for pollution levels in the districts. There are also apps that give you air quality readings: PRAISE-HK, AQHI App (government) plus international options like AIRVisual/IQAir.