The average concentration of PM2.5 hazardous particles was 30 micrograms per cubic meter, down 9.1 percent year-on-year.

细颗粒物（PM2.5）平均浓度为 30 微克/立方米，同比下降 9.1%。

Thailand's Department of Pollution says, air quality in Bangkok has fallen to harmful levels as the amount of hazardous dust particles known as " PM2.5" exceeded safe levels in more than 40 areas around the capital.

泰国污染部说，曼谷的空气质量已经降到有害水平，首都周围40多个地区被称为" PM2.5" 的有害尘埃颗粒超过了安全水平。