The Singapore National Environment Agency said that the Pollutant Standards Index levels were likely to remain in the “unhealthy” range for the next week.
Indonesia today deployed an extra 1,600 military personnel to fight forest and agricultural fires producing thick haze, as the smog closed schools in Malaysia and worsened air quality in Singapore.
Smog-belching fires are an annual problem during the dry season in Indonesia, where vast tracts of land are cleared on the huge islands of Sumatra and Borneo using illegal slash-and-burn methods.
FIA race director Charlie Whiting will meet with drivers and then teams in Singapore before they come to a decision on the race.
The air quality in a number of locations across Indonesia is so bad the government calls it “dangerous to breathe”.
Edgar SuEdgar Su/ReutersVehicles drive on a bridge over the Siak river in the haze covered city of Pekanbaru, Riau Province on the Indonesian island of Sumatra September 14.
Organisers said on Tuesday that the haze situation was volatile but there were no plans to change the schedules of the race and related events, including a post-race outdoor concert by rock icon Bon Jovi.
The smog is usually caused by firms and small-holder farmers clearing land adjacent to concessions for oil palm or pulp and paper.
The Formula 1 Singapore Grand Prix program is at present due to go ahead as planned, although organizers have warned the smoggy conditions are capable of altering hour by hour. Around 23,000 people in the province have been affected with acute respiratory infections caused by the haze since August.
The city-state regularly comes under a haze blown over from near-by Indonesia at this time of year, although it has triggered fears over visibility as the F1 circus rolls into turn this weekend.
Once the “hazardous” threshold is reached, the ministry will consider closing all primary and secondary schools, which typically sees students from ages seven to 16. Minister of Environment and Forestry, Siti Nurbaya, said Singapore already offered their aircraft to help extinguishing the smoke in Indonesia.
The Association of Southeast Asian Nations (ASEAN) addressed the issue with members signing up to an agreement on cross-border pollution in 2002.