PM10 (RSPM)

PM10 is airborne particulate matter with an aerodynamic diameter of 10 micrometres or less — the coarse-plus-fine fraction that penetrates beyond the upper respiratory tract into the bronchi. PM10 is the parameter SPCB officers most often cite when issuing show-cause notices to recycling plants, because it captures both the fine combustion fraction (PM2.5) and the coarse process dust (PM2.5-10) generated by shredding, granulation, screening, and material handling — the dominant fugitive source in a recycling line.

India's NAAQS (2009) sets PM10 limits at 100 µg/m³ (24-hour average) and 60 µg/m³ (annual mean), applicable uniformly across all area categories. WHO 2021 guidelines recommend 45 µg/m³ (24-hour) and 15 µg/m³ (annual) — Indian limits are 2-4x more permissive. Most Indian urban centres routinely exceed the Indian limit; annual PM10 in Delhi runs 200-240 µg/m³, Mumbai 90-130 µg/m³.

Measurement uses gravimetric samplers with a PM10 size-selective cyclone or impactor inlet, sampled over 24 hours onto pre-weighed filters. Continuous monitors use beta-attenuation or TEOM. The PM10 fraction is dominated by mineral dust resuspended from roads, construction, and bare ground, plus coarse combustion ash and process emissions — making it the parameter most responsive to enclosure, water-spray suppression and paved access roads at industrial sites.

For recycling plants, stack PM10 standards under SPCB CTO conditions are typically 30-50 mg/Nm³ at standard temperature and pressure, depending on industrial category and zone. Baghouse filtration with polyester or PTFE bags reliably achieves below 30 mg/Nm³ on PM10. Cyclones cut at roughly 10 µm so are useful as pre-cleaners but cannot meet PM10 emission limits alone — typical use is cyclone + baghouse in series, with the cyclone removing the 10-100 µm coarse fraction and protecting bag fabric. Continuous Emission Monitoring Systems (CEMS) with optical backscatter or beta-attenuation are mandatory on stacks above prescribed thresholds (boilers, kilns above 5 MW thermal). Fugitive PM10 around shredders and conveyors is the more common compliance failure point — water mist sprays at 0.5-2 L per tonne of feed reduce coarse fugitive PM10 emissions by 40-70%.