In the last seven months, Rajshahi city's level of small particulate matter (PM10) has doubled, indicating a rapid decline in the city's air quality, according to a report of Barendra Environment Development Voluntary Organisation.

Members of the Rajshahi-based NGO yesterday conducted the city's air quality tests at five points -- Talaimari, Railgate, Shaheb Bazar Zero point, Lakshmipur and BSCIC Mothpukur areas.

The report was created by comparing the organisation's researchers' findings from air quality tests with earlier measurements.

On April 8 this year, the average amount of PM10 (particulate matter less than 10 micrometres in diameter) measured at the five points was 109 micrograms per cubic metre. Yesterday, the average measurement showed PM10 climbed up to 230.6 micrograms per cubic metre -- a more than twofold increase in the span of seven months.

The organisation observed that even levels of smaller dust particles (PM2.5) increased significantly, according to the report.

On April 8, average level of smaller dust particles was 76.6 micrograms per cubic metre while the average measurement increased to 89.6 micrograms per cubic metre yesterday.

The measured levels are significantly higher than the World Health Organization's (WHO's) recommended guidelines of 150 micrograms per cubic metre for PM10 and 65 micrograms per cubic metre for PM2.5.

"The findings are concerning, as air pollution can have a serious impact on human health," said Zakir Hossain Khan, president of Barendra Environment Development Voluntary Organisation, while talking to The Daily Star.

Small dust particles can irritate the lungs and cause respiratory problems, while even smaller dust particles can enter the bloodstream and damage the heart, lungs, and brain, said Khan, also a former researcher of SGS.

The air pollution was caused in the city due to several factors, including construction works that are happening on a high scale. It was further worsened by a decrease of big trees and rainfall, said the president.

He hoped the air pollution may decrease if the Air Pollution Rules of 2022 are followed in the construction works.

The voluntary organisation of Rajshahi has been studying the city's air pollution since March 2022 as part of a research initiative.

In March 2022, the levels of PM10 and PM2.5 in the city's air were 76.6 and 66.2 micrograms per cubic metres respectively, the report said.