By Jiraporn Kuhakan
BANGKOK (Reuters) - Authorities in Thailand's capital warned people to wear face masks or stay indoors on Thursday after choking air pollution returned to Bangkok following months of clear air in one of the world's top tourist destinations.
The national Pollution Control Department issued the warning as the amount of hazardous dust particles known as PM 2.5 exceeded the safe level in three areas around the capital.
PM 2.5 is a mixture of liquid droplets and solid particles that can include dust, soot and smoke, one of the main measures of the Air Quality Index (AQI).
Thursday morning's AQI was 170, according to airvisual.com, which measures levels in cities worldwide.
The AQI is considered "unhealthy" when the level is above 150, meaning there is an "increased likelihood of adverse effects and aggravation to the heart and lungs among the general public", according to airvisual.com.
No cause was given for the deterioration in the air quality, which tends to get worse in the dry season from December to April.
Residents in the city of about 10 million complained about the air quality and problems such as asthma and allergies.
"Something is wrong with my health because I'm suffocating as I breathe," said Pitak Meesopa, a 58-year-old minibus driver who said that in the past year he had been suffering with an allergy and had to wear a mask frequently.
"My eyes are always in pain and itchy," he said.Air pollution forced the closure of some schools in Bangkok earlier this year and Thailand's northern provinces, including Chiang Mai, were hit by dangerous levels of dust particles in April.
(Editing by Timothy Heritage)