Living with smog

TIPS FOR PROTECTION

• Reduce or avoid prolonged and heavy exertion when the air is unhealthy, and sensitive groups should avoid all physical outdoor activity.

• Wear an air pollution mask when you have to go outdoors, but make sure the mask can block PM2.5 and that you wear it correctly with a tight seal around the face.

• It is not advisable to wear an air pollution mask for too long, especially for children, pregnant women, or those with respiratory, heart and lung diseases.

• Don't engage in physical exertion while wearing such a mask.

• When choosing an air purifier, decide first what contaminants you want to remove, because certain air filters are built to remove certain contaminants.

• Clean air delivery rate, filter efficiency and noise level are important factors to consider.

• An air purifier is able to remove 90 percent of PM2.5 in a 30-square-meter room with air pollution measurement standing at 100 micrograms per cubic meter. This is if the measurement taken at 1 meter's horizontal distance from the air purifier drops to 10 micrograms per cubic meter within 20 minutes after the machine starts working, according to Wu Jixiang, an expert with Shanghai Jiaotong University.

• Wind and precipitation can take PM2.5 away from the air, but acidic substances and nutrients attached to PM2.5 will increase the acidification and eutrophication levels of waters, affecting nutrient cycling and impacting the ecosystem, according to Chai Fahe, deputy head of the Chinese Research Academy of Environmental Sciences.