Crisis After Crisis: What is VOC?

According to reportage, ozone has overtaken PM2.5 as the primary air pollutant in Guangdong Province since 2015. When people almost instantly link air pollution to PM2.5 nowadays, it is odd to know that other elements in air could also be harmful. The case did not come singly but in pairs. Once in May, 2016, Beijing also suffered from ozone pollution.

Local environmental department urged to control emission of VOCs in the following year. What are VOCs and what are the connections with ozone?

VOCs refer to volatile organic compounds. These chemicals have a very low boiling point, meaning that they evaporate directly from liquid or solid things into the surrounding air, at room temperature. Actually with a smell contains VOCs, from perfumes to alcohol. The form more known to and disliked by people is the pungent smells in an apartment after decorating.

From this perspective, VOCs are harmful to our health and ventilation is a most helpful solution for household.

Apart from building materials, automobile exhaust as well contains lots of VOCs. And these emissions outdoors have a different impact on our living environment. It participates in the photochemical reaction process in the air and turn itself into ozone. Unlike PM2.5, ozone pollution is invisible and is likely to be severer when sunnier.

ozone pollution
When the sky appears blue and weather sunny, ozone in air may rise and cause pollution. Photo/

The ozone layer protects the earth from ultraviolet light 10 to 50 thousand metres above earth surface but causes damage to public health when it concentrates in air only 10-100 metres above surface.

Since ozone has no smell nor can it be seen like particulate matters, how should we know when it exceeds health limits in order to protect ourselves?

Thanks to a wide attention paid to PM2.5, people can search for real-time monitor statistics to see air conditions. As we can see from the following screenshot picture, the Air Quality Index monitors 6 elements and O3 refers to the ozone.

A screenshot from

As for ways to protect, unluckily, breathing masks might be able to stop PM10 and PM2.5, but not ozone. It is better to stay indoors on days polluted by ozone if your house is not a newly-refurbished one.

The public is more vulnerable to damage caused by ozone than PM2.5, so let’s hope the government will react faster than before and avoid as much harm as possible.

Yesterday is Earth Day. Here is a website where you can find interesting facts and take possible actions to contribute to protecting Mother Earth!


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