Nov 22, 2016 06:55 PM

Beijing Sets New Rules to Automatically Trigger 'Red' Smog Warnings

(Beijing) — Beijing has revised its air pollution alert system to allow environmental officials to issue "red" smog alerts in the city when air-quality readings exceed 500 — a move that appears meant to assuage public criticism over the city's perceived inadequate response to dangerous smog levels.

The air quality index (AQI) measures the level of pollutants in the air, especially the concentration of PM2.5 — fine cancer-causing particles smaller than 2.5 micrometers in diameter — as well as levels of PM10 pollutants and poisons such as sulfur dioxide.

The revised government contingency plan to tackle air pollution, released on Monday, aims to give more weight to the actual level of air pollution than the previous alert system did.

The move follows criticism of the city's environmental prevention authorities for failing to warn the public last year about toxic levels of air pollution and taking appropriate follow-up action.

Environmental authorities raised only an orange alert late in November 2015 when the city reported its worst smog on record, when levels of PM2.5 surged past 300 micrograms per cubic meter of air for five straight days, hitting over 900 micrograms per cubic meter at times.

The Beijing Municipal Bureau for Environmental Protection argued then that the orange alert was in line with rules set down in the country's air pollution warning system, which is more tied to how long air pollution will persist than it is with the actual pollution levels at the time.

Under the four-tier color-coded alert system, the government is required to issue a blue alert when the air is forecast to be heavily polluted or AQI readings exceed 200 for a sustained 24-hour period. A yellow alert is issued when the air is expected to stay polluted for 48 hours.

When the air is expected to remain heavily polluted for three days in a row — and seriously polluted on one of those days — an orange alert is merited. A red alert is triggered when the air quality remains very poor for four consecutive days, and is extremely bad for two of them.

Under a red smog alert, one-third of government-owned vehicles are to be taken off the roads, schools and kindergartens (preschools) are ordered to close, and construction work is suspended.

Under the revised government plan, vehicles whose emissions only meet National I or National II standards — usually cars and trucks at least 10 years old— will be banned from using roads within the Fifth Ring Road when an orange or red smog alert is issued.

Motor vehicles, particularly those with higher emissions, release 500,000 tons of pollutants into the air over Beijing annually, contributing to over 40% of PM2.5 levels in the spring, summer and autumn, and 30% of the pollutants in winter.

Contact reporter Li Rongde (; editor Calum Gordon (

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